Most Turbo XT motherboards booted up in standard 4.77 MHz speed and then had to be switched into turbo mode, either using an included DOS program or a keyboard command. Some used Ctrl+Alt+numeric keypad * key to switch speeds. And 4.77 MHz is 4.772726̅ MHz, to be exact -- it's divided from the 14.31818 MHz clock crystal, which also provides the 3.579545 MHz NTSC color burst frequency for CGA. That's why 7.16 and 9.54 MHz are popular CPU speeds for turbo XT systems, since they're also divided from the same crystal.
A lot of Turbo XT motherboards had an external switch to set "turbo mode", commonly intended to mount on the front panel. I NEVER saw one that used a "DOS program" to do that, though I've heard rumors of them. I've only seen ONE that used a keyboard command, which seems to have actually been pretty rare.
@@vwestlife That would explain it - the only Tandy MS-DOS machine I ever used were the Model 2000 - which was a weird machine to start with, beginning with it's use (VERY rare) of the 80186 and not PC compatable in many ways.
Every time I see one of these videos I'm more and more bummed that I trashed my old XT years ago. It had two interesting mods: (1) I found an article in Byte magazine that shows how to get 640K on the motherboard. It involved (as I recall 35+ years later!) adding a wire and scratching out a trace on the motherboard, adding a 74LS138 to an empty socket under the floppy drive, and replacing two banks of 64K chips with 256K chips. The hard part was finding the 74LS138 in quantity 1. (2) I replaced the full size 10 MB (5 MB?) drive with a pair of half-height 20 MB drives. Of course, the XT didn't have the necessary brackets for half-height drives, but I had just visited my parents and came back home with my old Erector Set. I turned out that the shortest Erector Set brackets were the exact size and spacing necessary, and the Erector Set screws were exactly the right size to screw into the drives to hold them to the brackets. Fun times.
The one-long, two-short beep pattern is standard on an XT I think for when the BIOS doesn't see the video card the DIP switches are set for. It had a Hercules card in it, so the switches would have been set for Mono, but you'd replaced it with a VGA, so you would need to set the switches for "other" to get rid of the error beeps.
11:46 That multifunction card in the 5150 was manufactured by American Computer & Peripheral (AC&P) in Santa Ana, CA and sold as the Abovefunction Card. Stason has the DIP switch settings on their website. A fun fact about AC&P is that they were the first to market an expansion device that allowed consumers to upgrade their 286-based ATs with i386 processors during the summer of '86. It was called the 386 Translator and was released shortly before the first 386-based desktops came out and before Intel's own AT upgrade card, the Inboard 386.
From what little I know of these machines, finding a Hercules card is one heck of a find! To my knowledge there aren't many out there, and what few there are are very expensive. Congrats!
There were absolutely JPEG viewers in 1995, though I am pretty sure they need A LOT more muscle then a 10MHz 8088 can provide. I was using one on my 80386DX 40MHz with a generic Trident SVGA card and decoding a single picture took about 30 seconds. But if the picture is 'interesting' enough, you put up with it. 😛
The hard part was downloading the picture in parts from Usenet, then stitching 5 or 6 parts together with a stitching program and then finally being able to open it. Not that I downloaded anything that way....
These are my favorite of your videos. Brings me back to a simpler time when a lot of us were very excited about each new machine that came out.. there was a lot of variety back then. Information was spread on BBS’ and in magazines and local user groups. Keep them coming, thanks.
You did it again! I mean, about a month ago I found a computer that looked just like one in the middle, it wasn't a genuine IBM machine, it was probably a clone. You are showing off hardware like the ones I'm encountering lately :)
IBM PCs were designed and built with such pervasive off-the-shelf parts to where their BIOS, their quality keyboard, and army tank armor like case enclosure, that is hard to see what they could do to distinguish their products from these clones. The keyboard was fairly well equalled by third party keyboard makers, the steel case enclusure could be duplicated easily enough. That just left the BIOS and yet that too got cloned sufficiently. If they'd had bothered to do some crucial custom chips here and there they could have held off clones for a bit longer.
When the clone craze of the early 90ies started, I hooked up with a couple of guys that were buying and selling used Atari 800 systems. My job was to go through the systems and make sure they worked. Then one of the guys started buying IBM clone mother boards and other components in bulk and I put then together. I would take a couple of the boxes he got home over the weekend and on Monday I would deliver 5 or 6 complete systems to sell! As payment I got to keep one of the systems for myself. I still have it in its flip open case, with half height, 5 1/4 inch floppies and hard drive.
The fact that the "Precision XT" badge is NOT where the recess is and it's also misaligned with it, really hurts my OCD LOL :) Very nice video! You don't need me to say this (I'm saying it for whoever is reading!) for diagnosing shorted components without risking anything you can inject some voltage with a current limited bench PSU, that way the component will warm up without failing in a destructive way.
The smaller hex head nut driver is also for tightening the motherboard mounts in most cases. When I got into building PC's in the 2010's you almost always wanted one of those because you had to screw in the mounts yourself.
They also fit those pesky external connector bosses that keep coming off with the connector screws. The original PC/XT drive mount screws were the smaller ones as well, and as I recall that made them a royal PITA because they could slip halfway into the slot, as well as being too tall to use with FH-HH adapter plates.
52:38 - That is an adaptec ACB-2072, can spot those a mile away. ST-506 RLL (2,7) controller card. The low-level Formatter program lives at C800:0ccc ...
It wasn't uncommon to pass along old computers to kids/teenagers. I think that's why it still saw some use up to 1996. For contrast, by that time I upgraded from a A1200 with 50mhz 68030 and 4MB+2MB of ram to a Pentium 5 75MHz and 8MB of ram.
Yep… I inherited a 1985ish Compaq Deskpro as my first computer in 1990, from then on, I traded or bought second hand a bunch of parts/upgrades till I bought my first brand new PC in 98. (A p1-200mmx)
Also explains the contents of the jpeg. Someone was trying to hide the dirty file they downloaded on their parents' pentium, which easily could have had a 5.25" drive B
Around that time we had a Pentium 200 MMX system in the living room but in my room I had a 5162 XT 286 with CGA, that I was given a couple years before, for tinkering and learning with, and before that I had our 5160 XT clone that was our main system in the 80s.
This is a great series. Looking forward to some more interesting PCs like AT and beyond lol. I remember struggling to play games on my family's XT clone and being jealous of my friend who had an AT machine with an EGA card and an NEC Multisync. That's when stuff started getting really compelling IMHO
So many throwbacks. Somewhere in my mums farmhouse, probably in the hayloft, I got a stack of xt-cartds. 2 complete computers worth and then a bunch of odd spares...I hope they have not frozen or rusted beyond repair for when I get time to set up my retro-mancave.
I used to work on IBM equipment when I worked at the University. We had a device with a Molex connector and a resister we used to test the power supply with. It was a bit more convenient than having a sacrificial device. Especially when going to different offices, it was easier than carrying a full hight device around which would have been what was available back then.
I was going to suggest that to Adrian. Especially one with Go/No-Go LEDs for voltage levels and meter lead test jacks for when you want exact measurements.
@@bobblum5973 The device we used, of course, didn't test anything itself. But those Switching PSUs needed a load or they will be damaged. So we would connect that to one Molex, and test the others and P8 and P9, Without the risk of zapping something important.
@Del Scoville Oh, I understood what you meant. I was just thinking of an upgraded version! 😁 Edit: A long time ago I used an LM3914 IC that converts an analog voltage to a bar graph LED display for something similar.
You do need quite a resistor though. Has to dissipate a couple amps, preferably, and that does get hot! I have a large sand-cast resistor on the 5V rail of my smoke-test harness. It's not enough alone, but with some unusable IDE HDDs to load 12V too, it does the job. Still, after 30 seconds, it's uncomfortable to touch. If I had a round tuit, I would build a test jig with automotive incandescent bulbs as dummy loads, but who has the time for that! haha
There is LXPic which is a JPG/GIF/PCX/BMP viewer, made for HP palmtops but runs on bigger machines, I used a lot on my V30 powered laptop, runs on an 8088/8086 with CGA :D
@8:44 I have those exact same screw drivers, same colors and everything. And like you, I've had them for over 20 years and also had no idea what they were for most of that time.
8:35 - Betting that his 'PC tool kit' was the exact same type that's been around _forever_ and still to this day, with the zippered pouch of screwdrivers that came with some plastic tweezers, a little hypodermic needle-type springy grabber claw thing, and that sickly-amber translucent plastic tube with yellow end caps for storing screws/etc in. :D
45:46 - You need a metal end plate on your memory card adapter, the same one that is on that Hyper Clock card at 38:17, that way you would not put in the memory card adapter in reverse.
@1:00:00 Norton Commander 4 did have a picture viewer built in that could do JPEG's, but I think that you needed at VGA to work properly. I don't remember if it demanded a 286 or if it worked on a 8088.
I had that same kit! It was sold at Radio Shack and had number of little tools in it and was pretty useful. I still have the nutdrivers and the little tube (for holding small parts I guess.)
multiple beeps at startup mean the mono adapter was changed to another one. Hercules and MDA are set at DIP switches and are initialized by PC or XT BIOS, and CGA too. VGA and EGA are initialized by their own BIOS so DIP switches at m/b should be set to "no video adapter" position
I remember using an original IBM-PC pre-launch because my employer were a multi-mainframe operator and IBM used to let us test new stuff. We had 360/158, 3031, 3033 and 3081 mainframes and an 8100 mini where I worked.
9:10 - Nut-drivers have been around forever. Those hex/slotted screws were very common/ Back in the 1960's and 1970's they were called 'Sheet Metal Screws'; they were also self-tapping. Now, they've been replaced by tapped-thread screws with Phillips, TORX, etc. slottage. BT,W, the *Xcelite* brand of nut-drivers (literally) smell like BARF! :)
I inherited a PC repair kit, just as cheap 286s were displacing "upmarket" XTs and 286s... I quickly found the "Compaq" driver handy for the occasional Torx screw... but always wondered what the two socket drivers were for. You have finally cleared up my confusion... thanks. Poor old ST-225... a noble creature living out it's life as little more than a dummy-load. :( ;)
Might be an interesting video (second channel maybe!) to demonstrate the cassette and external floppy ports on the 5150. Would be fun to see four floppy drives in action!
Not only can the CR2032 batteries leak (occasionally), but I've actually had a couple of occasions where they had shorted, and stopped the machine from even powering on and/or booting. If you have power or boot issues, this is worth checking.
Congrats on finally getting ahold of a Hercules card. Some retro computer enthusiasts made it sound like the Hercules was the Holy Grail of graphics cards.
Funny how things have progressed. In 1996, a machine from 1987 was ancient. As a rule of thumb, everyone replaced machines that were two or three years old. But today, we have 3rd Gen i5 Machines (upgraded with SSDs) at work, that are more than 10 years old. These run Windows 10 perfectly and are in everyday use.
I've always known of them as "nut drivers" because you can use them for tightening or loosening hex nuts, but they do also work on hex-headed bolts and screws of course.
In my experience you typically need sufficient load for the power supply to start up. Just the mother board was not enough. We used to use a hard disk or a floppy drive to provide sufficient load.
You mentioned at 2:08 that if you bought a 64k machine, you couldn't run DOS; I don't think this is true, you could definitely run DOS under 64k of RAM. I think around 32k was the limit.
A fun trick I remember from tinkering with those 5150 machines back in the late 90's. On the speaker bracket or maybe the cable, a lot of those had this fabric tie-on tag that had a QA code along with the machine's birth date.
I seem to remember that one (or similar) was on the speaker lead on an XT I worked on ages ago. Can't recall what was on it or if it was still readable, machine would have been around 10 years old at that time.
@@adriansdigitalbasement don't forget to re-upload the Live Stream to TH-cam later.. so we can all see it 🙂 ....... love you PC archeology videos ... man! how I miss Dave @RetroSpector78 ... he use to do mainly PC's and PC clones..
25:04 It isn't limited to just floppy drives in vintage PCs. I get that in my model aircraft engines too. They just get put away and forgotten for 10, 15, 20, 30+ years sometimes and the castor oil in them...one of the lubricants in their modern day fuel and the only lubricant in ye olden times...turns into glue. Locks the whole engine up tight. Knowing how to free them up and make them run nicely has saved me a fortune and gotten me some really nice engines on the cheap!
Those little tantalum beads... I have 3 Siemens paper tape punch / reader machines from the erarly 80s that all have these bead caps in them as part of the power section. On 2 of the machines, they burst into flames when the machine was plugged in !!
Adrian, on the 5150 and 5160 some of the PSUs required a current threshold for the PSU to remain active. If you don’t have the Floppy drives or MFM plugged in they do not draw enough current to keep the PSU on. From what I could tell they were not plugged in when you tried powering it on and checking for shorted caps. There was likely nothing wrong with the cap, it was simply the PSU. This is the exact problem I had when I got my first 5160.
The place that built my 1988 XT clone (in the AT case) was called "PC Fitness Club". ;) I'm sure it was the lowest local advertised price for 640k. I remember it as a barebones strip mall storefront with foldable banquet tables inside. I couldn't afford the branded clones like AT&T, Epson and Leading Edge sold at fancier computer stores.
Hmm, 1988. That’s when I moved from my TRS-80 Model III to a generic clone (286? 8 MHz?) cobbled together by one of those shopping-center joints in Dallas called Lucky Computer. Luckily, it was an OK machine, except the monitor frequently needed the neck board resoldered. The interim fix each time was a hard whack on top with the flat of the hand. That machine looked about like the third one here.
I had that exact IBM PC AT at one time, it got hit by lightning one day and stopped working, weirdly the power supply would sometimes switch on the PC automatically at random until I eventually left it unplugged, was soon parted out and replaced with an Am386/DX 40.
id love to see a video from you about the upgrades they have for these ibm's and build the ultimate version, and then show what things they can do, like what programs or operating systems they can run. ive been thinking of buying one because i love to tinker but i dont know if it would just be destop art, and never be touched. love your videos!
I have many Philips screws that also have the hex head so you can use either. Useful with some cheap ones where the Phillips cross gets damaged for whatever reason (probably cheap metal).
A very interesting video. I enjoyed your descriptions of the functions of the main board and all the peripherals. I attended the first introduction and demonstration of the IBM in Toronto, way back when, and as a C64 user at the time, I thought, what is the big fuss it doesn't come with anything. It just proved, that the initials IBM brought a way more creditability than the machine could provide.
WOW, this brings back memories. My first IBM clone was similar to the bottom one. It had a 20MB MFM hard drive. I'll never need anything bigger than that! Since DOS was so awkward and cumbersome, I used a program called Directory Scanner. It showed the entire directory tree and used the function keys to manipulate actions.
I regret not having the space to keep some of the vintage computers I've owned over the years. I had a 5150 in pristine condition and a 5160 that needed some cleaning up. Also an IBM expansion chassis that was new in box. I have kept some items like a Compaq portable and a very early Zenith laptop. It's always interesting to see people remaining interested in the early ecosystem of the IBM PC and compatibles.
I do have CGAs with two RCA connectors. So it can't be a give away it's EGA - however the EGA switches are ;) Also these NEC MFM 5.25" hard drives are super reliable - I have several and they just work like new compared to Seagate drives of these era...
When I first started working in 1983, We already had a number of non-XT PC's with casette drives. 128k and we ran all sorts of BASIC programs...Within 2 years we went to XT's and then 512 AT's. ...and hundreds of floppys of driver disks
I worked for a computer company in the late 90's early 2000's we used to use a basic 286 machine to copy floppy disks. There was also another 286 machine we used as a basic print server.
About the JPGs... If I remember correctly from a technology TV show from that time, there was a way to send messages encoded within a "valid" JPG and was used back then to send personal messages in Usenet and others. The JPG would look "normal" in a graphics software, but using a "decoding" program would show the message. I wonder if the other JPG you were talking about would be a "message JPG" or related to this. However it's surprising that someone do that and then forget to format / destroy that private data in a disk... But there would occur a lot of situations that could explain why. Either way, this was very interesting and made me remember about that old technology.
@@helgew9008 Hiding, yes. However 'uuencoded' data was the common method for transmitting files across USENET and was not 'hidden', so you would simply say this is encoded.
@@orangeActiondotcom That's not what the OP was talking about. UUEncode was just a way to stuff 8-bit data in 7-bit text, so it could be sent across a text-only medium. The OP is talking about modifying a JPG image to hide data within the picture itself. I doubt that's what actually happened here. My money's on it being exactly what it appeared to be -- "homework" downloaded from Usenet, that may or may not have ever been viewed on an XT.
There was a graphics conversion program called hijaak or hijack that may have supported jpeg. It had all kinds of wacky formats supported for input / output and I sort of used it as a benchmark back in the day.
I had some dos picture viewer program that would display .gif .jpg etc as best as it could with your display adapter (worked with the usual hgc/cga/ega/vga). In that type of machine it will slowly fill the screen.
@Adrian`s Digital Basement: I have a same XT clone case on 48:00 over there. Can you tell me which motherboard is in there> and do you have more information on that half height disk / drive mounting bracket (in the middle ,that black one?), which my same case is missing...? ( is it the same measurement from the original IBM?) If so i try to see if i can send you an e-mail if possible..
Nostalgic.... Used to build clones back in the 80s. Hercules was such a step forward to show graphs and charts. I wrote low level procedures and run Intel RMX80 real time operating system on the clones
We used a lot of tants mid 90s, they were more expensive than electrolytics at the time but were seen as higher quality and longer life. They didnt leak but we also started to see a few fires caused by ones that were a few years old. Our power source was typically huge NiCad packs that could deliver loads of current, one would go short and instantly incinerate. We moved to OScon caps over a few years, these seemed to be short lived. The POST beeps are probably a colour/mono mismatch on the dip switches
Yep, I have those nut drivers. Got them in a repair kit that I bought from Fry's Electronics back in the day. Still have them somewhere and they were very useful.
Not sure if you noticed. When you pulled out the hard disk controller at 36.27, the small cable comes out the top. When you tested the drive you at 43.02 you had the cable coming out at the bottom.
Well it matched the graphics of the mac (unsurprisingly) unless you had ega or vga. Basically just cga looked worse, but in retrospecfive, better than the original C64 🙂
Did you ever encounter Compaq's version of MS-DOS 3.31, which was the same as 3.3, but it had the capability of addressing hard drives greater than 32Meg, which was (If I recall) the big limitation otherwise.
I was kind of surprised the third one turned on, from the camera angle it looked like the cpu was not fully seated. It looked like the end towards the rear of the case had worked out a little bit I guess if it did it was still making connection.
Yeah, no sh*t. Recently, the company I work for moved, and they had literally hundreds of old, out-of-date machines they (meaning, me) had to remove the hard drives from (security precautions- the drives had customer info), so each one had to be lugged over to a table for disassembly, and many of them were absolute beasts, weight-wise, especially the old Compaq units!
As I posted a month ago on your MFM test video that I worked for IBM in the early 80's and had one of the first 5150's made. It had 16K of ram with 3 empty banks of sockets to max out to 64k on the motherboard. Memory was very expensive in 1981. I got it for an employee discount price of about ??? (can't remember what I paid). At the time IBM was charging $400 for a single sided 360K diskette drive which I couldn't really afford. So I ended up using the cassette port to save and load Basic programs. I just used a $50 Radio Shack cassette player / recorder and standard audio tapes. My recollection was that it ran at 1500 baud and it was rock solid saving / loading programs. I had previously owned a TRS-80 Model 1 and its cassette interface was completely unreliable. It failed to reload saved programs 9 out of 10 times. That's why I sold it. I kind of regretted that later as the Z80 processor on board was faster than my 5150. But if you can't save anything, what's the point? I also had a Hercules graphics card (clone) that had single color graphics (green, amber, white) depending what type of phosphor your monitor had (IBM's was green). The resolution was great but the 4.77 MHz processor on the 5150 didn't have enough horsepower to move that many pixels around much. It was painfully slow, especially when Microsoft released their first version of Windows.
Very interesting video thanks Adrian. But.. @56.:46 you are talking about dhrystones and whetstones? I have no idea what you are talking about? Can you explain on a future video please? Cheers.
on the earlier clones (1980's & 90's) look for the UL sticker on the power supply. The ones that actually passed UL were a LOT more reliable and quieter (and more expensive) than the cheap ones often used. Many of them are now fire hazards due to the cheap components used and the safety components being left out so be careful. (sometimes it looked like a backwards Ru) like the second pc opened. Just saw the third computer. Leadman was one of the better vendors (it was also UL approved); and all power supplies of the clones were NOT equal. The cheaper ones were guaranteed to fail early. I watched 4 or 5 local competitors fail because they were using the cheapest power supplies. By the late 80's the computer shopper Magazine (11x17 x 1000+ pages) was the ultimate shopping directory. If you built a computer using the cheapest of each parts, it was guaranteed to NOT work (which kept me in business fixing them). Take the cheapest part, at 10-15% to the price and THATS where you price shopped.
I used to have a PC AT(?) clone with a flip up top on the case, you pressed a button on each side of the lid and it would just flip up. It had a 20mb hard drive and ran dos 5 I think? It was given to me by my public school librarian. It is probably the reason I'm a software developer today.
This is getting me hyped up for the pile of XTs and ATs I've had in the garage since picking them up in the North West Computer Museum fundraiser a few months back. You never know what treasures might be inside!
IIRC all PC floppies were double sided, but the early ones were 40 track single density. Everyone else went to 80 track single sided as the next step up (to approx 180kB)
All that comes to mind on these old PCs is how bloody expensive they were and how many hundreds of hours we all spent rebooting them 630 times to get them to work if they went bad. I sold a video editing product that lived in a 286 clone computer which I supplied to my clients but as I recall, those bare board 286s were still $700 each. I've seen literally thousands of these-era computers piled up in dumpsters, about to be shredded.
Back in the day, I modded several I/O cards with 16550 UARTS, removing the old chip & installing socket) for BBS computers, to use US Robotics Courier HST, 14,400 baud “ish” modem
Every video you make is really cool and interesting to me and I watched them work basically repetitively, but when you said “a hole that is missing” i’m like “if there was a hole that was missing, it wouldn’t be there“
My first PC was around '88, and it was basically the same specs as your 3rd computer. An Epson Apex 100/20 at 10 or 4.77 MHz, 640k, CGA, a 5¼" floppy, and a whopping 20MB hard drive. Had a 2400 baud external modem and used the computer for BBS, Fidonet, and some DOS games (usually pirated off of boards). At the time I wasn't a big computer geek and didn't even know it was old specs. That computer has a special place in my memories, along with the C64 I used previously... and neither of which I have anymore, naturally.
I know the Apex, a friend had one, with cga composite output to a green monochrome monitor. His had two floppy drives and nothing else. It was the shoebox floppy storage days, he would play several dos games and some required floppy swapping during parts. I had a more mundane xt clone like the last one showed in this video, with cga rgb color crt, single floppy and the ST-238R. Yeah we each also had a printer for the ocasional school work with wordstar etc, which was the "excuse" of the day to have our parents get us a computer. For me it was the second, coming from Apple //c which i still had back then, late 80ies.
AFAIK, the cassette port was not entirely unused, just maybe not used for its intended purpose- some early PC-based point of sale systems used the cassette port to open the cash drawer!
I think vwestlife had a video a while back where he got the cassette port working for a diagnostic cassette from IBM...the only cassette software known to be distributed for the 5150 PC 😅
Wow. That "Precision" unit is eerily similar to the Zenith Data Systems PC I started out with back in the 80's. those nut drivers are the same as the ones I still have and still use often from when I worked at radio shack in the mid 90's. Ahhh memories... Can't wait to get the $ together to rebuild my first pc (or as close as I can get to it.)
"Precision" was a Portland, Oregon business computer and services company from the 1990's. When we did business with them, they re-sold AST desktops and laptops to business customers along with their own private-labeled whitebox clone PCs. At one point they were located at 1111 SE Stephens, just next to Ladds Addition.
are these things worth anything ? i used to have a 2 person U-Matic and Betacam video editing workbench, [ His and Hers ] made of 2 house doors, supported on 6 pillars of these IBM PC, XT, AT 286 metal bricks unfortunately had to dump them all in 2003 when i moved. ironically I kept my old video equipment and still have it, but is probably worthless now.
7:04 Gave this an FCC ID search and indeed, Linde is the manufacturer... and this is apparently the only thing they ever submitted. One and done. 24:00 The root might have slipped by.... the tantalum cap was next to resistors that emit heat. That's probably why it failed.
Most Turbo XT motherboards booted up in standard 4.77 MHz speed and then had to be switched into turbo mode, either using an included DOS program or a keyboard command. Some used Ctrl+Alt+numeric keypad * key to switch speeds. And 4.77 MHz is 4.772726̅ MHz, to be exact -- it's divided from the 14.31818 MHz clock crystal, which also provides the 3.579545 MHz NTSC color burst frequency for CGA. That's why 7.16 and 9.54 MHz are popular CPU speeds for turbo XT systems, since they're also divided from the same crystal.
Wow, great information. Thank you.
A lot of Turbo XT motherboards had an external switch to set "turbo mode", commonly intended to mount on the front panel.
I NEVER saw one that used a "DOS program" to do that, though I've heard rumors of them.
I've only seen ONE that used a keyboard command, which seems to have actually been pretty rare.
@@bricefleckenstein9666 In Tandy's version of MS-DOS you can type MODE FAST or MODE SLOW to change the CPU speed.
@@vwestlife That would explain it - the only Tandy MS-DOS machine I ever used were the Model 2000 - which was a weird machine to start with, beginning with it's use (VERY rare) of the 80186 and not PC compatable in many ways.
Every time I see one of these videos I'm more and more bummed that I trashed my old XT years ago. It had two interesting mods:
(1) I found an article in Byte magazine that shows how to get 640K on the motherboard. It involved (as I recall 35+ years later!) adding a wire and scratching out a trace on the motherboard, adding a 74LS138 to an empty socket under the floppy drive, and replacing two banks of 64K chips with 256K chips. The hard part was finding the 74LS138 in quantity 1.
(2) I replaced the full size 10 MB (5 MB?) drive with a pair of half-height 20 MB drives. Of course, the XT didn't have the necessary brackets for half-height drives, but I had just visited my parents and came back home with my old Erector Set. I turned out that the shortest Erector Set brackets were the exact size and spacing necessary, and the Erector Set screws were exactly the right size to screw into the drives to hold them to the brackets.
Fun times.
I do want to try the 640K mod but not on my original 5-slot mainboard!
The one-long, two-short beep pattern is standard on an XT I think for when the BIOS doesn't see the video card the DIP switches are set for. It had a Hercules card in it, so the switches would have been set for Mono, but you'd replaced it with a VGA, so you would need to set the switches for "other" to get rid of the error beeps.
Exactly. Probably the same situation with the second XT since that was probably mono too - even if it is a bit more musical than the beep bip bip 😊
11:46 That multifunction card in the 5150 was manufactured by American Computer & Peripheral (AC&P) in Santa Ana, CA and sold as the Abovefunction Card. Stason has the DIP switch settings on their website.
A fun fact about AC&P is that they were the first to market an expansion device that allowed consumers to upgrade their 286-based ATs with i386 processors during the summer of '86. It was called the 386 Translator and was released shortly before the first 386-based desktops came out and before Intel's own AT upgrade card, the Inboard 386.
52:42 It's an Adaptec ACB-2072. Just look directly over the ISA-connector right next to the EPROM.
From what little I know of these machines, finding a Hercules card is one heck of a find! To my knowledge there aren't many out there, and what few there are are very expensive. Congrats!
On top of that, there were a *lot* of single-chip Hercules clones and CGA/Herc chips out there, like the Tamarack TD3088 and Paradise PVC4.
I love your pc archeology videos. I love doing things like this myself but watching you saves me money and garage space. :-)
There were absolutely JPEG viewers in 1995, though I am pretty sure they need A LOT more muscle then a 10MHz 8088 can provide. I was using one on my 80386DX 40MHz with a generic Trident SVGA card and decoding a single picture took about 30 seconds. But if the picture is 'interesting' enough, you put up with it. 😛
The hard part was downloading the picture in parts from Usenet, then stitching 5 or 6 parts together with a stitching program and then finally being able to open it. Not that I downloaded anything that way....
52:40 The model number of the Adaptec card is in the middle of the card, just above the connector contacts: ACB-2072
These are my favorite of your videos. Brings me back to a simpler time when a lot of us were very excited about each new machine that came out.. there was a lot of variety back then. Information was spread on BBS’ and in magazines and local user groups. Keep them coming, thanks.
You did it again! I mean, about a month ago I found a computer that looked just like one in the middle, it wasn't a genuine IBM machine, it was probably a clone. You are showing off hardware like the ones I'm encountering lately :)
IBM PCs were designed and built with such pervasive off-the-shelf parts to where their BIOS, their quality keyboard, and army tank armor like case enclosure, that is hard to see what they could do to distinguish their products from these clones.
The keyboard was fairly well equalled by third party keyboard makers, the steel case enclusure could be duplicated easily enough. That just left the BIOS and yet that too got cloned sufficiently.
If they'd had bothered to do some crucial custom chips here and there they could have held off clones for a bit longer.
When the clone craze of the early 90ies started, I hooked up with a couple of guys that were buying and selling used Atari 800 systems. My job was to go through the systems and make sure they worked. Then one of the guys started buying IBM clone mother boards and other components in bulk and I put then together. I would take a couple of the boxes he got home over the weekend and on Monday I would deliver 5 or 6 complete systems to sell! As payment I got to keep one of the systems for myself. I still have it in its flip open case, with half height, 5 1/4 inch floppies and hard drive.
The fact that the "Precision XT" badge is NOT where the recess is and it's also misaligned with it, really hurts my OCD LOL :) Very nice video! You don't need me to say this (I'm saying it for whoever is reading!) for diagnosing shorted components without risking anything you can inject some voltage with a current limited bench PSU, that way the component will warm up without failing in a destructive way.
The smaller hex head nut driver is also for tightening the motherboard mounts in most cases. When I got into building PC's in the 2010's you almost always wanted one of those because you had to screw in the mounts yourself.
They also fit those pesky external connector bosses that keep coming off with the connector screws. The original PC/XT drive mount screws were the smaller ones as well, and as I recall that made them a royal PITA because they could slip halfway into the slot, as well as being too tall to use with FH-HH adapter plates.
And how did I miss this from 2 months ago...where was I? You wore the Forgotten Machines shirt...Thank you, Adrian...again!!! You are amazing!
52:38 - That is an adaptec ACB-2072, can spot those a mile away. ST-506 RLL (2,7) controller card. The low-level Formatter program lives at C800:0ccc ...
It wasn't uncommon to pass along old computers to kids/teenagers. I think that's why it still saw some use up to 1996. For contrast, by that time I upgraded from a A1200 with 50mhz 68030 and 4MB+2MB of ram to a Pentium 5 75MHz and 8MB of ram.
Yep… I inherited a 1985ish Compaq Deskpro as my first computer in 1990, from then on, I traded or bought second hand a bunch of parts/upgrades till I bought my first brand new PC in 98. (A p1-200mmx)
I had a mac 128k up until 1996, so I agree
Also explains the contents of the jpeg. Someone was trying to hide the dirty file they downloaded on their parents' pentium, which easily could have had a 5.25" drive B
Around that time we had a Pentium 200 MMX system in the living room but in my room I had a 5162 XT 286 with CGA, that I was given a couple years before, for tinkering and learning with, and before that I had our 5160 XT clone that was our main system in the 80s.
This is a great series. Looking forward to some more interesting PCs like AT and beyond lol. I remember struggling to play games on my family's XT clone and being jealous of my friend who had an AT machine with an EGA card and an NEC Multisync. That's when stuff started getting really compelling IMHO
So many throwbacks. Somewhere in my mums farmhouse, probably in the hayloft, I got a stack of xt-cartds. 2 complete computers worth and then a bunch of odd spares...I hope they have not frozen or rusted beyond repair for when I get time to set up my retro-mancave.
I used to work on IBM equipment when I worked at the University. We had a device with a Molex connector and a resister we used to test the power supply with. It was a bit more convenient than having a sacrificial device. Especially when going to different offices, it was easier than carrying a full hight device around which would have been what was available back then.
I was going to suggest that to Adrian. Especially one with Go/No-Go LEDs for voltage levels and meter lead test jacks for when you want exact measurements.
@@bobblum5973 The device we used, of course, didn't test anything itself. But those Switching PSUs needed a load or they will be damaged. So we would connect that to one Molex, and test the others and P8 and P9, Without the risk of zapping something important.
@Del Scoville Oh, I understood what you meant. I was just thinking of an upgraded version! 😁
Edit: A long time ago I used an LM3914 IC that converts an analog voltage to a bar graph LED display for something similar.
You do need quite a resistor though. Has to dissipate a couple amps, preferably, and that does get hot! I have a large sand-cast resistor on the 5V rail of my smoke-test harness. It's not enough alone, but with some unusable IDE HDDs to load 12V too, it does the job. Still, after 30 seconds, it's uncomfortable to touch.
If I had a round tuit, I would build a test jig with automotive incandescent bulbs as dummy loads, but who has the time for that! haha
@@nickwallette6201 It had a 25 Watt ceramic resister. We didn't make them, they came with the tool kits provided to the University directly from IBM.
There is LXPic which is a JPG/GIF/PCX/BMP viewer, made for HP palmtops but runs on bigger machines, I used a lot on my V30 powered laptop, runs on an 8088/8086 with CGA :D
35:27 I always remember swapping a lot of serial ports with 16550's in all my cards. Had to have fast ports for my modems. 🤠👍
I watch your vids, and I think of all the stuff I used to know, that I have let myself forget as tech progressed. The nostalgia hits hard. :D
I like your explanations of computers of this era, because I started repairing PCs when there were 486s and IDE drives already.
@8:44 I have those exact same screw drivers, same colors and everything. And like you, I've had them for over 20 years and also had no idea what they were for most of that time.
8:35 - Betting that his 'PC tool kit' was the exact same type that's been around _forever_ and still to this day, with the zippered pouch of screwdrivers that came with some plastic tweezers, a little hypodermic needle-type springy grabber claw thing, and that sickly-amber translucent plastic tube with yellow end caps for storing screws/etc in. :D
45:46 - You need a metal end plate on your memory card adapter, the same one that is on that Hyper Clock card at 38:17, that way you would not put in the memory card adapter in reverse.
@1:00:00 Norton Commander 4 did have a picture viewer built in that could do JPEG's, but I think that you needed at VGA to work properly. I don't remember if it demanded a 286 or if it worked on a 8088.
I had that same kit! It was sold at Radio Shack and had number of little tools in it and was pretty useful. I still have the nutdrivers and the little tube (for holding small parts I guess.)
Yup! Same here. Identical. Little tube goes in the middle of the case. Mines full of screws. Had the kit for 25+ years at least.
The musical post tones at 54:25 leads me to believe that the computer thinks it's midnight on 1st January somewhere in Scotland..
multiple beeps at startup mean the mono adapter was changed to another one. Hercules and MDA are set at DIP switches and are initialized by PC or XT BIOS, and CGA too. VGA and EGA are initialized by their own BIOS so DIP switches at m/b should be set to "no video adapter" position
I remember using an original IBM-PC pre-launch because my employer were a multi-mainframe operator and IBM used to let us test new stuff. We had 360/158, 3031, 3033 and 3081 mainframes and an 8100 mini where I worked.
9:10 - Nut-drivers have been around forever. Those hex/slotted screws were very common/ Back in the 1960's and 1970's they were called 'Sheet Metal Screws'; they were also self-tapping. Now, they've been replaced by tapped-thread screws with Phillips, TORX, etc. slottage.
BT,W, the *Xcelite* brand of nut-drivers (literally) smell like BARF! :)
I inherited a PC repair kit, just as cheap 286s were displacing "upmarket" XTs and 286s... I quickly found the "Compaq" driver handy for the occasional Torx screw... but always wondered what the two socket drivers were for. You have finally cleared up my confusion... thanks.
Poor old ST-225... a noble creature living out it's life as little more than a dummy-load. :( ;)
The UART information. Holy cow, you just brought back old knowledge from the back of my brain.
That was really fun! Hang onto that genuine Hercules card - that thing deserves more credit!
Nice tour down memory lane ...
Thanks for sharing 🙂
Might be an interesting video (second channel maybe!) to demonstrate the cassette and external floppy ports on the 5150. Would be fun to see four floppy drives in action!
I think VWestlife did a video about the cassette port. It's called "Nobody ever used the IBM PC with a cassette tape recorder... until now"
All the PC cabinets I've purchased over the years have come with combo hex head philips screws that worked with those nut drivers.
Not only can the CR2032 batteries leak (occasionally), but I've actually had a couple of occasions where they had shorted, and stopped the machine from even powering on and/or booting. If you have power or boot issues, this is worth checking.
I had this exact thing happen on a late 90s Dell Optiplex a few years ago. Refused to POST until I changed the battery
35:40 is a DFI card. Diamond flower INC.
Congrats on finally getting ahold of a Hercules card. Some retro computer enthusiasts made it sound like the Hercules was the Holy Grail of graphics cards.
Maybe the color one, its so rare...
@@freeculture ...That this is the first time I remember hearing about it.
Funny how things have progressed. In 1996, a machine from 1987 was ancient. As a rule of thumb, everyone replaced machines that were two or three years old. But today, we have 3rd Gen i5 Machines (upgraded with SSDs) at work, that are more than 10 years old. These run Windows 10 perfectly and are in everyday use.
I still use my windows 7 laptop that I bought brand new in 2013. It's my daily driver.
I've always known of them as "nut drivers" because you can use them for tightening or loosening hex nuts, but they do also work on hex-headed bolts and screws of course.
Yep. I'm not sure the drivers were meant to work on IBMs specifically, so much as IBM used common size fasteners which that kit had tools for.
In my experience you typically need sufficient load for the power supply to start up. Just the mother board was not enough. We used to use a hard disk or a floppy drive to provide sufficient load.
You mentioned at 2:08 that if you bought a 64k machine, you couldn't run DOS; I don't think this is true, you could definitely run DOS under 64k of RAM. I think around 32k was the limit.
A fun trick I remember from tinkering with those 5150 machines back in the late 90's. On the speaker bracket or maybe the cable, a lot of those had this fabric tie-on tag that had a QA code along with the machine's birth date.
Ah nice, I've seen the tag but don't recall ever looking at what was written on it b
I seem to remember that one (or similar) was on the speaker lead on an XT I worked on ages ago. Can't recall what was on it or if it was still readable, machine would have been around 10 years old at that time.
@@adriansdigitalbasement don't forget to re-upload the Live Stream to TH-cam later.. so we can all see it 🙂 ....... love you PC archeology videos ... man! how I miss Dave @RetroSpector78 ... he use to do mainly PC's and PC clones..
25:04 It isn't limited to just floppy drives in vintage PCs. I get that in my model aircraft engines too. They just get put away and forgotten for 10, 15, 20, 30+ years sometimes and the castor oil in them...one of the lubricants in their modern day fuel and the only lubricant in ye olden times...turns into glue. Locks the whole engine up tight.
Knowing how to free them up and make them run nicely has saved me a fortune and gotten me some really nice engines on the cheap!
Those little tantalum beads... I have 3 Siemens paper tape punch / reader machines from the erarly 80s that all have these bead caps in them as part of the power section. On 2 of the machines, they burst into flames when the machine was plugged in !!
Your videos are pure joy to watch, thanks for these I recently got a working 5155 portable IBM and was trying to get the floppy working!
Adrian, on the 5150 and 5160 some of the PSUs required a current threshold for the PSU to remain active. If you don’t have the Floppy drives or MFM plugged in they do not draw enough current to keep the PSU on. From what I could tell they were not plugged in when you tried powering it on and checking for shorted caps. There was likely nothing wrong with the cap, it was simply the PSU. This is the exact problem I had when I got my first 5160.
The place that built my 1988 XT clone (in the AT case) was called "PC Fitness Club". ;) I'm sure it was the lowest local advertised price for 640k. I remember it as a barebones strip mall storefront with foldable banquet tables inside. I couldn't afford the branded clones like AT&T, Epson and Leading Edge sold at fancier computer stores.
Hmm, 1988. That’s when I moved from my TRS-80 Model III to a generic clone (286? 8 MHz?) cobbled together by one of those shopping-center joints in Dallas called Lucky Computer. Luckily, it was an OK machine, except the monitor frequently needed the neck board resoldered. The interim fix each time was a hard whack on top with the flat of the hand. That machine looked about like the third one here.
I had that exact IBM PC AT at one time, it got hit by lightning one day and stopped working, weirdly the power supply would sometimes switch on the PC automatically at random until I eventually left it unplugged, was soon parted out and replaced with an Am386/DX 40.
id love to see a video from you about the upgrades they have for these ibm's and build the ultimate version, and then show what things they can do, like what programs or operating systems they can run. ive been thinking of buying one because i love to tinker but i dont know if it would just be destop art, and never be touched. love your videos!
I have those exact hex driver tools from a toolkit I got 20 odd years ago from Tandy or Maplin in the UK; they often come in useful.
I have many Philips screws that also have the hex head so you can use either. Useful with some cheap ones where the Phillips cross gets damaged for whatever reason (probably cheap metal).
Lots of memories selling 5150s and 5160s back from 1984-1987 while in college. The clones were just starting to take off during that time.
Begin the clone war has. 🙂
Beautiful blue ribbon cable at 10:12
A very interesting video. I enjoyed your descriptions of the functions of the main board and all the peripherals. I attended the first introduction and demonstration of the IBM in Toronto, way back when, and as a C64 user at the time, I thought, what is the big fuss it doesn't come with anything. It just proved, that the initials IBM brought a way more creditability than the machine could provide.
WOW, this brings back memories. My first IBM clone was similar to the bottom one. It had a 20MB MFM hard drive. I'll never need anything bigger than that!
Since DOS was so awkward and cumbersome, I used a program called Directory Scanner. It showed the entire directory tree and used the function keys to manipulate actions.
I regret not having the space to keep some of the vintage computers I've owned over the years. I had a 5150 in pristine condition and a 5160 that needed some cleaning up. Also an IBM expansion chassis that was new in box.
I have kept some items like a Compaq portable and a very early Zenith laptop.
It's always interesting to see people remaining interested in the early ecosystem of the IBM PC and compatibles.
I do have CGAs with two RCA connectors. So it can't be a give away it's EGA - however the EGA switches are ;) Also these NEC MFM 5.25" hard drives are super reliable - I have several and they just work like new compared to Seagate drives of these era...
I do recall one of these clones - I threw away some years ago- which had some metal resorts plus a button to open it. It opened like a car hood.
When I first started working in 1983, We already had a number of non-XT PC's with casette drives. 128k and we ran all sorts of BASIC programs...Within 2 years we went to XT's and then 512 AT's. ...and hundreds of floppys of driver disks
I worked for a computer company in the late 90's early 2000's we used to use a basic 286 machine to copy floppy disks. There was also another 286 machine we used as a basic print server.
About the JPGs... If I remember correctly from a technology TV show from that time, there was a way to send messages encoded within a "valid" JPG and was used back then to send personal messages in Usenet and others. The JPG would look "normal" in a graphics software, but using a "decoding" program would show the message. I wonder if the other JPG you were talking about would be a "message JPG" or related to this. However it's surprising that someone do that and then forget to format / destroy that private data in a disk... But there would occur a lot of situations that could explain why. Either way, this was very interesting and made me remember about that old technology.
The technique of hiding information within other information is called steganography.
Yes, its called 'uuencoding', he mentioned this exact procedure by name in the video.
@@helgew9008 Hiding, yes. However 'uuencoded' data was the common method for transmitting files across USENET and was not 'hidden', so you would simply say this is encoded.
@@orangeActiondotcom That's not what the OP was talking about. UUEncode was just a way to stuff 8-bit data in 7-bit text, so it could be sent across a text-only medium. The OP is talking about modifying a JPG image to hide data within the picture itself.
I doubt that's what actually happened here. My money's on it being exactly what it appeared to be -- "homework" downloaded from Usenet, that may or may not have ever been viewed on an XT.
@@nickwallette6201 Exactly what I was trying to say, thank you!
There was a graphics conversion program called hijaak or hijack that may have supported jpeg. It had all kinds of wacky formats supported for input / output and I sort of used it as a benchmark back in the day.
I had some dos picture viewer program that would display .gif .jpg etc as best as it could with your display adapter (worked with the usual hgc/cga/ega/vga). In that type of machine it will slowly fill the screen.
@@freeculture And hey, if you're a teenager, and all you have is an XT with a 360K floppy drive, CGA, and a modem... that's enough to get by! haha
@Adrian`s Digital Basement: I have a same XT clone case on 48:00 over there. Can you tell me which motherboard is in there> and do you have more information on that half height disk / drive mounting bracket (in the middle ,that black one?), which my same case is missing...? ( is it the same measurement from the original IBM?) If so i try to see if i can send you an e-mail if possible..
Nostalgic.... Used to build clones back in the 80s. Hercules was such a step forward to show graphs and charts. I wrote low level procedures and run Intel RMX80 real time operating system on the clones
I'm interested in those JPGs, for.. science.
I can't believe he didn't upload them uuencoded... for science.
We used a lot of tants mid 90s, they were more expensive than electrolytics at the time but were seen as higher quality and longer life. They didnt leak but we also started to see a few fires caused by ones that were a few years old. Our power source was typically huge NiCad packs that could deliver loads of current, one would go short and instantly incinerate. We moved to OScon caps over a few years, these seemed to be short lived. The POST beeps are probably a colour/mono mismatch on the dip switches
Yep, I have those nut drivers. Got them in a repair kit that I bought from Fry's Electronics back in the day. Still have them somewhere and they were very useful.
Not sure if you noticed. When you pulled out the hard disk controller at 36.27, the small cable comes out the top. When you tested the drive you at 43.02 you had the cable coming out at the bottom.
The Leading Edge I had growing up had a Hercules card in it. It was really the best way to play SimCity.
Well it matched the graphics of the mac (unsurprisingly) unless you had ega or vga. Basically just cga looked worse, but in retrospecfive, better than the original C64 🙂
Did you ever encounter Compaq's version of MS-DOS 3.31, which was the same as 3.3, but it had the capability of addressing hard drives greater than 32Meg, which was (If I recall) the big limitation otherwise.
I may actually have a copy of that, I remember seeing it...
I still have a copy of it. It was absolutely necessary for the Compaq Portable that I own.
From memory nut drivers was also good for tighten and loosen the metal motherboard standoffs / screw holders...
I was kind of surprised the third one turned on, from the camera angle it looked like the cpu was not fully seated. It looked like the end towards the rear of the case had worked out a little bit I guess if it did it was still making connection.
Hey Adrian, all these machines beep angrily at you because you replaced the graphics card with a VGA and didn't change the DIP switches accordingly.
If I'm not mistaken, Sirius Victor was Chuck Peddle's company that turned into the UK's Apricot.
Sore back and eye strain; the only treasures I ever got from those machines.
Gotta get a good chair and turn the brightness down. It helps tremendously.
Sore back from trying to move them around?
@@adriansdigitalbasement I can imagine 🎬
@@adriansdigitalbasement Yessir! ohhhh :-(
Yeah, no sh*t. Recently, the company I work for moved, and they had literally hundreds of old, out-of-date machines they (meaning, me) had to remove the hard drives from (security precautions- the drives had customer info), so each one had to be lugged over to a table for disassembly, and many of them were absolute beasts, weight-wise, especially the old Compaq units!
As I posted a month ago on your MFM test video that I worked for IBM in the early 80's and had one of the first 5150's made. It had 16K of ram with 3 empty banks of sockets to max out to 64k on the motherboard. Memory was very expensive in 1981. I got it for an employee discount price of about ??? (can't remember what I paid). At the time IBM was charging $400 for a single sided 360K diskette drive which I couldn't really afford. So I ended up using the cassette port to save and load Basic programs. I just used a $50 Radio Shack cassette player / recorder and standard audio tapes. My recollection was that it ran at 1500 baud and it was rock solid saving / loading programs.
I had previously owned a TRS-80 Model 1 and its cassette interface was completely unreliable. It failed to reload saved programs 9 out of 10 times. That's why I sold it. I kind of regretted that later as the Z80 processor on board was faster than my 5150. But if you can't save anything, what's the point?
I also had a Hercules graphics card (clone) that had single color graphics (green, amber, white) depending what type of phosphor your monitor had (IBM's was green). The resolution was great but the 4.77 MHz processor on the 5150 didn't have enough horsepower to move that many pixels around much. It was painfully slow, especially when Microsoft released their first version of Windows.
Very interesting video thanks Adrian. But.. @56.:46 you are talking about dhrystones and whetstones? I have no idea what you are talking about? Can you explain on a future video please? Cheers.
on the earlier clones (1980's & 90's) look for the UL sticker on the power supply. The ones that actually passed UL were a LOT more reliable and quieter (and more expensive) than the cheap ones often used. Many of them are now fire hazards due to the cheap components used and the safety components being left out so be careful. (sometimes it looked like a backwards Ru) like the second pc opened. Just saw the third computer. Leadman was one of the better vendors (it was also UL approved); and all power supplies of the clones were NOT equal. The cheaper ones were guaranteed to fail early. I watched 4 or 5 local competitors fail because they were using the cheapest power supplies. By the late 80's the computer shopper Magazine (11x17 x 1000+ pages) was the ultimate shopping directory. If you built a computer using the cheapest of each parts, it was guaranteed to NOT work (which kept me in business fixing them). Take the cheapest part, at 10-15% to the price and THATS where you price shopped.
I used to have a PC AT(?) clone with a flip up top on the case, you pressed a button on each side of the lid and it would just flip up. It had a 20mb hard drive and ran dos 5 I think? It was given to me by my public school librarian. It is probably the reason I'm a software developer today.
42:54 I heard "This is a pretty quiet MF'n hard drive"
This is getting me hyped up for the pile of XTs and ATs I've had in the garage since picking them up in the North West Computer Museum fundraiser a few months back. You never know what treasures might be inside!
IIRC all PC floppies were double sided, but the early ones were 40 track single density. Everyone else went to 80 track single sided as the next step up (to approx 180kB)
All that comes to mind on these old PCs is how bloody expensive they were and how many hundreds of hours we all spent rebooting them 630 times to get them to work if they went bad. I sold a video editing product that lived in a 286 clone computer which I supplied to my clients but as I recall, those bare board 286s were still $700 each. I've seen literally thousands of these-era computers piled up in dumpsters, about to be shredded.
Back in the day, I modded several I/O cards with 16550 UARTS, removing the old chip & installing socket) for BBS computers, to use US Robotics Courier HST, 14,400 baud “ish” modem
I actually had a 386 SX I bought at a yard sale that came in that same clone case with the turbo and reset buttons
Every video you make is really cool and interesting to me and I watched them work basically repetitively, but when you said “a hole that is missing” i’m like “if there was a hole that was missing, it wouldn’t be there“
My favourite kind of video. PC Archeology. Nice!
WOW ! that brings me back a ways , I owned an IBM similar to that , loaded programs from the 5 1/4 floppy
My first PC was around '88, and it was basically the same specs as your 3rd computer. An Epson Apex 100/20 at 10 or 4.77 MHz, 640k, CGA, a 5¼" floppy, and a whopping 20MB hard drive. Had a 2400 baud external modem and used the computer for BBS, Fidonet, and some DOS games (usually pirated off of boards).
At the time I wasn't a big computer geek and didn't even know it was old specs. That computer has a special place in my memories, along with the C64 I used previously... and neither of which I have anymore, naturally.
I know the Apex, a friend had one, with cga composite output to a green monochrome monitor. His had two floppy drives and nothing else. It was the shoebox floppy storage days, he would play several dos games and some required floppy swapping during parts. I had a more mundane xt clone like the last one showed in this video, with cga rgb color crt, single floppy and the ST-238R. Yeah we each also had a printer for the ocasional school work with wordstar etc, which was the "excuse" of the day to have our parents get us a computer. For me it was the second, coming from Apple //c which i still had back then, late 80ies.
AFAIK, the cassette port was not entirely unused, just maybe not used for its intended purpose- some early PC-based point of sale systems used the cassette port to open the cash drawer!
Ha! That's pretty awesome. Seems like a good use of such a thing. Probably relied on the motor on signal to activate the solenoid.
I think vwestlife had a video a while back where he got the cassette port working for a diagnostic cassette from IBM...the only cassette software known to be distributed for the 5150 PC 😅
Wow. That "Precision" unit is eerily similar to the Zenith Data Systems PC I started out with back in the 80's. those nut drivers are the same as the ones I still have and still use often from when I worked at radio shack in the mid 90's. Ahhh memories... Can't wait to get the $ together to rebuild my first pc (or as close as I can get to it.)
I worked on some Zenith Z248s (I think) a long, long time ago. Neat machines, 286 running an ISA backplane and proc/mem card.
"Precision" was a Portland, Oregon business computer and services company from the 1990's. When we did business with them, they re-sold AST desktops and laptops to business customers along with their own private-labeled whitebox clone PCs. At one point they were located at 1111 SE Stephens, just next to Ladds Addition.
I have a Zenith Z-248 computer and I still play vintage computer games. The old 10 Mbyte MFM full 5 1/4 size hard drive still run fine.
are these things worth anything ?
i used to have a 2 person U-Matic and Betacam video editing workbench, [ His and Hers ]
made of 2 house doors, supported on 6 pillars of these IBM PC, XT, AT 286 metal bricks
unfortunately had to dump them all in 2003 when i moved.
ironically I kept my old video equipment and still have it, but is probably worthless now.
More of these videos please love them, can you also make a video about microsolutions parallel port drives, thanks
7:04 Gave this an FCC ID search and indeed, Linde is the manufacturer... and this is apparently the only thing they ever submitted. One and done.
24:00 The root might have slipped by.... the tantalum cap was next to resistors that emit heat. That's probably why it failed.
52:32 Adaptec ACB-2072 ? Its written on the PCB..