Amiga 1000 repair - No audio output
ฝัง
- เผยแพร่เมื่อ 8 ก.ค. 2022
- #16bit-dance-party #amiga #repair
I picked up this complete Amiga 1000 from a viewer back in January 2020. Since then, I hadn't had a chance to dig into finding out what is wrong and fixing it.
Finally, that day has arrived, so let's find out what's wrong with this and fix it.
--- Video Links
My video from Jan 2020 when I picked up this machine:
• Picking up an Amiga 10...
Amiga Test Kit:
github.com/keirf/amiga-stuff/...
Adrian's Digital Basement Merch store:
my-store-c82bd2-2.creator-spr...
Adrian's Digital Basement ][ (Second Channel)
/ @adriansdigitalbasement2
Support the channel on Patreon:
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-- Tools
Deoxit D5:
amzn.to/2VvOKy1
store.caig.com/s.nl/it.A/id.16...
O-Ring Pick Set: (I use these to lift chips off boards)
amzn.to/3a9x54J
Elenco Electronics LP-560 Logic Probe:
amzn.to/2VrT5lW
Hakko FR301 Desoldering Iron:
amzn.to/2ye6xC0
Rigol DS1054Z Four Channel Oscilloscope:
www.rigolna.com/products/digi...
Head Worn Magnifying Goggles / Dual Lens Flip-In Head Magnifier:
amzn.to/3adRbuy
TL866II Plus Chip Tester and EPROM programmer: (The MiniPro)
amzn.to/2wG4tlP
www.aliexpress.com/item/33000...
TS100 Soldering Iron:
amzn.to/2K36dJ5
www.ebay.com/itm/TS100-65W-MI...
EEVBlog 121GW Multimeter:
www.eevblog.com/product/121gw/
DSLogic Basic Logic Analyzer:
amzn.to/2RDSDQw
www.ebay.com/itm/USB-Logic-DS...
Magnetic Screw Holder:
amzn.to/3b8LOhG
www.harborfreight.com/4-inch-...
Universal ZIP sockets: (clones, used on my ZIF-64 test machine)
www.ebay.com/itm/14-16-18-20-...
RetroTink 2X Upconverter: (to hook up something like a C64 to HDMI)
www.retrotink.com/
Plato (Clone) Side Cutters: (order five)
www.ebay.com/itm/1-2-5-10PCS-...
Heat Sinks:
www.aliexpress.com/item/32537...
Little squeezy bottles: (available elsewhere too)
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--- Links
My GitHub repository:
github.com/misterblack1?tab=r...
Commodore Computer Club / Vancouver, WA - Portland, OR - PDX Commodore Users Group
www.commodorecomputerclub.com/
--- Instructional videos
My video on damage-free chip removal:
• How to remove chips wi...
--- Music
Intro music and other tracks by:
Nathan Divino
@itsnathandivino - วิทยาศาสตร์และเทคโนโลยี
WooHoo! So glad to see the A1000 working again! And yeah, I wouldn't have found that issue.
As for the RCA jacks, yeah they gave me problems and that is when I decided to stop so I didn't do any more damage. :-) I knew it needed someone who knew what they were doing, and you popped right into my mind.
Great video and great repair!!!
Sorry it took so long! The problem (to not spoil it for anyone seeing this before finishing) was one I rarely encounter. It's just such a rare issue, and yes would have been hard to find.
I had a friend who sold his car to be able to buy an Amiga 1000 when it was launched. His girlfriend broke up with him a few days later. It was worth it according to him.
That's the spirit!
@@AlejandroJCura Yes, I exchanged an apartment (lease) for an Amiga 3000 a few years later. The deal itself included a 300MB Microscribe SCSI hard drive (a monster), as big as a moped motor that I used for a USENET BBS.
What a legend!
"A friend"
This computer was like the dream machine when I was a kid. It had legendary status because no one around could even dream of afford it
This brings back memories. About 30 years ago I modified my Amiga 1000 to retrofit the low pass filter defeat that was present in later model Amigas. For those who don't know, the Amiga 1000 had a fixed 3Khz low pass filter in the audio path which resulted in pretty muffled audio quality. So despite the Paula being able to operate at sample rates up to 28Khz and thus reproduce frequencies up to 14Khz, high frequencies above 3Khz were always lopped off by the filter.
The A500 and A2000 added a switchable filter - the control line which dims the power LED also bypasses the 3Khz low pass filter in later models, giving a much sharper but also aliased sound that Amiga mods became known for, however most MOD's were written with the filter being off in mind. (In fact tracker programs allowed a MOD to set the filter on or off)
To retrofit this functionality I had to trace the audio path from the Paula to output socket via the opamps etc - all without the benefit of having a circuit diagram. I also had to trace the source of the LED dimming control signal.
I ran into the same problems as you - trying to trace those signals while the machine is running, but with the Kickstart daughter board being right in the way. I don't remember exactly how I did it but I suspect I removed the board from the case and measured on the bottom like you did.
To actually implement the switching I interrupted the signal path before and after the low pass filter and used two quad CMOS switches (which are capable of switching analogue signals) controlled by the LED dimming signal to either pass the signal through the low pass filter or bypass it. This circuitry was mounted on a tiny Vero board stood off from the motherboard on small standoff legs but below the daughter board.
It worked great and allowed me to hear MOD files the same way owners of later Amiga's did. I gave that Amiga 1000 away in 2009 and although I hadn't used it for years by that time and it had sat in a basement it was still in perfect working condition. These days I really regret giving it away as the A1000 is now considered a classic...
Hope that A1000 made it to a good home. A mod like that "requires" someone to put it through its paces.
The later Amigas also vastly simplified the filter circuit
Just got to admire how that one plucky resistor could take the heat and carry on like nothing was happened.
It didn't lose *any* of its capacity to resist current, smack bang still in spec!
Who's the tough resistor that won't cop out when there's heat all about?
Caps are the 1st thing I try after checking the power when audio is concerned. Well done! I would have also recapped everything and replaced the 100 ohm even if it read properly.... it's been stressed and may eventually break down sooner rather than later.
That add-on ram board for the kick start was called the "writeable control store" daughterboard.
Gotta love the grandaddy of all Amigas. My first Amiga, my first 16 bit system, my first desktop computer, first computer with seperate keyboard, first computer with Monitor, the first computer that made my parents say "Wow computers can do that?".
16:44 Maybe it was due to the 1010 drive being so close to the Monitor. I've had that issue before! Some people also have issues with the built in drive when the monitor is on top. C= added a heavy metal plate under the Amiga 1080 monitor to block the interference.
true. And at one point sitting on the SMPSU. That cant help?.
Ah yes, the magnetic field of CRT-monitor. Loudspeakers had to be avoided also.
Sound problems on Amiga (basically all models) very often boil down to problems on the 12v/-12v circuitry, and this wasn't an exception. If the machine works, but it's without audio, it's usually something with the 12v/-12v rail, additionally the floppy drive might not work, if the problem is with the PSU. So that kind of gives early hints during diagnostics. In any case, great work, good repair!
not to mention the controller lag.
Man, you should see my A1000 with the first version of the Insider memory expansion. It has 48 RAM chips on it, so it's a tight fit into the CPU socket, even without a ROM kick board on top. Having a whopping 2MB of RAM back in the day made me feel like a king. 8)
Stop throwing out disks, BTW. Floppies are actually very reliable. Each drive has slightly different alignment, so just rewrite those disks in a "good" drive to fix them. I need to re-align the drive in my A1000 one of these days.
I had a computer shop from 1982- 1992 and your experience with 3.5” FDD is exactly what we had in the 80’s. They were very temperamental. 5.25” were rock solid.
It does not help that 3.5" media was for a few years utter garbage. Like half of the disks from a box wouldn't even properly format on the first try.
Sorry kiddie you are mistaken or full of sh!t completely.... I suspect the latter
Oh no! We are not getting right to it! LOL! Thanks for another great video Adrian!
Sometimes I try to change things up a little :-) Muhahaha
@@adriansdigitalbasement Peanuts :-)
Was that also a GreatScott reference at the end, or has Adrian just been watching too many of his videos lately?
your joy of fixing and old system is so freaking contagious
Super jealous you have an Amiga 1000 as.ivr.wanted one for about 20 years but super happy to see another one alive
When changing out internal drives back in the day, I also used IBM 720k drives by modding the disk sense switch. Fine memories. I wonder if Amiga will be back with a smart phone design.
Thanks for the upload! Great repair Adrian. Im learning alot from your videos.
How you could've known it's not the opamp: the opamp doesn't actually have a connection to GND, so it's impossible for it to produce a short to GND :)
(The opamp doesn't need GND, it essentially works anywhere* inside the -5V to +12V range, the input signals "bring" their referencing in with them. *[there's dead zones near the rails, -3V to +11V/4Vcm really])
That's such an obvious point that I've never even noticed, excellent tip 👍 I hate opamps I've never understood them but luckily I've a friend who does just a phone call away..
I guess it is common to have a 0v rail connected to say the + or - opamp input, then there could have been a short path to 0v. However not in this case it seems. Easy thing to assume.. Or there could have been a rail to rail short (pin 4 to 11 or whatever it is on the TL074 without looking)..
@@g0bzy They seem to use it in a weird hybrid between single- and dual-supply connection. They connected it between +12 and - 5V and then biased it to ~2V .. so for the opamp it looks like + - 7V.
I would love to have a desktop Amiga, simply because they're so expandable compared to the 500, 600 and 1200 models (and yes I'm aware of expansions for those!!), trouble is that other people with more money than me also want them and have priced us lower-specced people out of buying them to enjoy them... :(
Imagine living with the fact you owned a 2000 back in the day but gave it away 20 years ago. I could probably track down and afford one now if I really wanted to, but I want MY 2000 back, not one that's been through other people's hands and gone through who knows what. Oh, well. That's life.
I always feel a little sad when I hear that little end tune and see the "Adrian's Digital Basement" logo disappearing into the distance... another brilliant show is over. Can't wait for the next one! :-)
Yeah, this is true.
Can't get enough of Amiga videos
Very nice fix and love the DeluxePaint images :)
The previous video with this machine in it is from February 2020 no less. Admittedly 2.5 years ago was not yesterday, but being just a bit pre (widespread) human malware makes it feel like that was AGES ago, doesn't it?
Congrats on making that spicy 16-bit dance party possible, btw!
Nice job Adrian. I especially liked the way you narrowed down the short to the cap using the resistance test.
Excellent trouble shooting. Love it. The A1000 is a great machine. My first Amiga was an A500 and I didn't know that the filter was hardware only on the A1000 until recently. Great video.
The Amiga 1000 is one of the best looking computer designs - and on top of that, inside is a great, groundbreaking machine too. So good to see one bought back to life.
I've seen some people who immediately recap any older machines they get, so I'm glad you didn't so you had a chance to make an interesting troubleshooting video!
This was great :) Love how you put so much effort to fix those lovely computers and got them working. Thanks for an awesome video Adrian. You keep inspiring me!
great video i really enjoy it to the end.
Excellent troubleshooting Adrian! I would of not suspected the cap,but sure enough!. Another nice A1000 back in the world.
Adrian, flexing that big brain man! I felt like a surgeon for a second...lol. That music is awesome for the day...
Great fix...
watching video like this is much more better than the last james bond movie, it's unbelieveble how smart you detect issue on board and fix it, thanks
Amazing detective work, thank you very much!
Hahaha love the rant on floppy disks, reminded me of myself while installing System 7 while using salvage disks and having to restart from the beginning on every read error
Good job troubleshooting! Old electrolytics definitely short but not too often. Nice machine.
Good Job Adrian. You are the best.
Awesome video. I still remember the first time I saw the Amiga 1000. It was a small mom and pop computer store in Anaheim Ca. I so wanted that machine but was never able to afford it. By the time I could the 1000 had been discontinued so I bought a 500.
Awesome video. I really loved the A1000, and now I know why all the awesome STM mods i used to bring in to the store to demo on the A1000 sounded like someone was holding a pillow over the speakers. That would drve me nuts.
Great job, I thought for a moment that the sound socket mounting points would fail altogether, but all turned out OK.
I had to find a picture of the Amiga 1000 ports to be sure, but I think you lucked out and got the red and white audio jacks in the right position, thereby foiling Sod's Law. Nice work on this very cool machine, and what a surprising solution.
I've been too swamped with work this year to watch any ADB/ADBII videos. Last I checked in, Adrian Agonistes was figuring out the future of candy reviews and [S]MMCs. It has been so very enjoyable catching up on my backlog of your videos the past week! I also enjoy hearing you name-checked by other great retro-enthusiasts like David Murray.
good fix, I did manage to spot the audio on the schematic but would not have guessed the cap either. My money was on the op amp.
Actually none of the opamp pins is connected directly to GND, so it was quite obvious that short is somewhere else. 🙂
Awesome trouble shooting skills. I used to be a component level tech on the AM-1000 Alpha Micro system.
*Salutes*
I sooo agree with your decision to keep it original. 🤗
Along with Branchus Creations, your videos have motivated me to fix electronics again. It started off with a Macintosh SE/30 and I have a few more projects to work on. They include a Compaq Portable III & a TurboGrafx Express.
I once had a 2000 in the shop that had been in a thunderstorm. He remembered to unplug it, but forgot to disconnect the phone line from the modem. I assume it wasn't a direct hit, cuz the machine wasn't melted. :-) But the hit took out his modem, fried the rs232 driver & receiver on the motherboard, and most likely because of that link you mentioned from Paula to the serial port, took out Paula as well. It didn't fry any traces though... which I have seen on video and joystick voltage pins before they added fuses.
Great fix! An Amiga 1000 is a precious possession! And wow - you just passed 25 million views! Thats not a small feat. Congratulations on that!
25 thousand, close
On the whole channel maestro.
@@robertgijsen whoops. Blushing because you called me maestro, I’m usually called Einstein for my comments.
From memory, there were a couple of really early games that booted in place of kickstart to utilise that additional 256K of ram.
Dragon's Lair did that. That's the only game I am aware of (might be more). It required 1M of RAM, or just 512k if you had an A1000. :-) Also, A-Max (the Mac emulator) could use that as RAM.
Ah that's pretty cool!
Awesome as always! Coleco Adam.
Great job!
17:30 Open the sliding window and take a look at the disk. Often the magnetic coating just strips off the disk entirely (it looks like grooves in the disk when this happens). That material then sticks to and contaminates the drive head and has to be cleaned off.
That was a nice Great Scott moment there at the end
I know you don’t want to mod the audio filter but it is easy to add the missing circuit to make it switchable with the LED software switch
Oh man this was my dream machine when I was a youngster. I had to save every penny for years while waiting for the much cheaper A500 before finally getting one.
The Amiga 1000 still looks good today!
Thank you Adrian for ALL your videos, i learn a lot with them, and i enjoy them all!. I have 2 amigas (500 and 1200), with no power supply and i am hopping to see a video of how to make a BRAND NEW from actual components.
I also have 2 ZX clones from south america (CZ and TK) CZ from Argentina -Czerweny- this works perfectly, and TK Brazil -Microdigial-, with no power supply, and a MSX CPD 200.... but with no cartridges to try.
Again. Thank you for your videos, they are all very instructive s.
Jan Beta has a number of videos of the creation of "modern" power supplies for various computers. Here's his one for an A600 (should be the same for a 500/1200) th-cam.com/video/TCKNZjhbWaw/w-d-xo.html
@@manxam2k Hi Manxam. Thank you for your comment. I am subscribed to Jan Beta too. I will check the video you suggest.
I try to not use the old 8bit computers, because in my case, I have a CZ Spectrum 48k+ of Argentina and a Talent MSX DPC 200 computer too (working both), but i have 2 amigas and a tk85 -a brazilian zx81 clone- and non of them have power supply, so... i want to refurbish them and make all work properly and then i will continue working with emulators, because for me all are like a treasure from i was a kid, and i want them in the formal glory of the past :). Again Thank you for you comment.
This Atari vs ST debate you mention at 2:37 is something I have never heard of before! How about doing a video on it? 😏😛
My first CGA monitor for my first PC was an Amiga monitor. I can't remember what model it was but it looked just like what you're using here. I am surprised to find yours still works. I continued using mine as a composite video monitor long time after CGA was irrelevant. But I thought all monitors eventually died. Every large TV we ever had eventually died because the one of the high voltage lines eventually started arcing. My dad said it was because the insulation dried out after a lot of use. So I just assumed all monitors eventually died.
02:35 "Atari vs ST". That would be a nice comparison :P
It's fun watching and remembering the hassle with floppies that dies etc. :) What an upgraded world we live in today
You know… the audio channel on the serial port sounds (pun not intended) weird but it was probably for doing DTMF tones. Never considered but much cheaper than adding a dedicated codec chip for dtmf dialing. ;) Brilliant.
Ooh good point! I was trying to think which serial devices would want to also output sound, you’re right that a modem is probably the most likely culprit
@@kaitlyn__L I have the 1680(?) 1200 baud modem for the A1000 so I can check (once I get out of storage).
My only other thought was using it for IVR (Interactive Voice Response) but I can’t imagine that on a 512k Amiga… but it has the ability to do voice synthesis.
Always love your videos Adrian. You're a Don. x :D
I used to have an original A1000 I got to see if I wanted to go Amiga after my Atari 8-bits. It was impressive, but the cost of peripherals and software were too high as I was just starting my family and my Atari with an MIO and hard drive managed for another few years until I bought a PC.
The audio out from the left channel to the serial port was a weird feature of the Amigas, I remember reading the idea was that Paula could send audio data to the modem (an Amiga specific modem, since the pin was not a standard RS-232 pin). There was also an audio in on the port that got mixed with the right channel (but never digitized), presumably so the dial tone from the modem could be played over the speakers. I know Commodore sold a 9600 baud Amiga branded modem; no idea if it actually supported those pins.
Wow an actual ram drive literally.
That was my first computer! I loved that thing
Great work, as always!
Nice fix.
Love the bin. It's where all the evil 3.5" go. The final circle of hell for them.
An original owner of this machine myself. Now I have been playing with my present 1000. Added a Rejuvenator which was a major trial for someone with my skills. Also got it booting from emu68 pistorm with som graphic issues in rgb mode. Finally trusted drive went bad on me but I am not going totake apart my 1010 to get another. Oh and I broke my rj11 keyboard connector in the process but that looks like an easy fix.
Most repair channels always suspect the electrolytic caps first. Even to the point of replacing all the caps before turning on.
blindly replacing all the caps before even turning the machine on to test it first and check if there even is a reason to suspect the caps really are bad is a modern trend and kinda BS in my opinion ...
by all means, popping the hood for a thorough visual inspection before powering up a piece of old tech in unknown condition is absolutely the right thing to do...
... but shotgunning all the caps without checking if the machine even works to begin with ??? naaaah ...
@@KenjiUmino Depends on the caps. The junk surface mount electrolytics from the 90s should be replaced on principal, but it doesn't usually come down to principal since they're often obviously leaking. Through-hole caps from the 80s that pass a visual inspection can be left alone.
Bugs me to see people blindly replacing caps regardless. Dare i say it shows lack of knowledge. Yes check the cap ESR, but if good, why replace it.
27:25 Adrain: I accused you unjustly!
OP Amp: Bro!
maybe for sheilds and stuff that is tarnished and rusted you could sand them if needed and put on some galvanized spray it should stop them rusting again. or tarnishing.
Hey, I know the guys who wrote the software of the original disk you wrote the Kickstart image over 😄
So glad to see this finally resolved! I love mine and it was such a ground breaking machine. I should update my own video. You’ve inspired me!
33:55 - 16-bit dance party right there :D
You know I had meant to overlay that on the video, but forgot!! Will need to put a hashtag :-)
36:00 Amiga 1995? I think you meant to say 1985. Because we were selling Amiga 500s and 2000s at the store I worked at in the 1990s. ; ) You DA MAN! Nice repair!
We missed the 1000. Ended up with one of the very first imported 500's with KS 1.2 and a US keyboard. We got 1.3 as a free upgrade from Commodore a few months later.
Sweet, your A1000 is freakin' workin'! ;) I did figure "opamp voltage problem" early on, but I enjoyed how you traced the actual root cause of that. Oh, how about a poll on that burned survivor resistor! :D /o\
Kickstart 1.3 is actually very compatible with modplayers, games, etc. But what happens on a machine with only 512K is that the OS hogs half of it, and this is unexpected, especially if it's going to load a big song or something. However, over 90% of trackloaded games software required only 512K memory until quite late, say published up until late 1991. Workbench type programs and games requiring the OS (Workbench or CLI showing) - if it's made after 1987, it probably won't start. 256K chip total and even trackloaded software will not have room for tracks, loader, and program.
Regarding floppy disks: they are very reliable indeed, and hold the information perfectly for more than 3 decades from a single write. I would say some manufacturers like Maxell struggled until 1988, but that's it. There are no bad brand DD disks after that; noname brands are perfect. It has all to do with storage - of the drive, and the disks. I would never put a disk in a drive I didn't check, and I would never put an unchecked disk in a perfect drive.
TL;DR: If you inspect the drives and the disks, something must physically happen to 3.5" disks to make them lose information.
About what happened: (Because it's as interesting as finding what's wrong with hardware!)
The A1000 obviously didn't write different data to the test disk. This is what could have happened:
1) The disk writer or the disk reader(s) could have transferred residue to the disk from their heads. Fix by cleaning the disk and the drives.
2) The disk was an HD disk, but the writer drive was DD, and the adapter (correctly) applies normal DD power to drive coercivity, which though the values are similar, is not enough and will result in a very weak write. (Not weak enough to work one second and not work hours later, though.)
3) The disk was a DD disk, but the writer drive was HD, and the adapter expected a DD drive.
4) Something happened to the disk between insertions. (Mechanical or it was placed near a very strong, changing magnetic field.)
5) The disk already had dust inside it, and it moved around so as to land on tracks that prevented loading.
2 and 3 are unlikely and can be solved easily technically. 4 is something that only you know, maybe you remember dropping it, or putting it on an unknown speaker (some modern TV soundbars and similar have extremely powerful, unshielded magnetic fields!)
This leaves 1 and 5. 5 is fixed by opening the flap, turning the disk while blowing the dust into the corners (or opening the disk to clean it properly). I think 1) is the most likely for the short timespan. One of the drives had dirt on the heads, and you did place the disk in two different drives. Dust came on it from one to the other.
I write at length because I've had so few disks from 1988 onwards fail on me, and if one did I have most of the time been able to format it. It's almost always how they're stored, or in the rare case a bad drive when writing. If written properly, the magnetic information is stored very securely on 3.5" disks. Even if dust and mold gets inside them, you can clean it off and get the information back.
Do I see an external Gotek in the A1010 form factor? I would like to see a vid on that.
I love WB 1.3 boot screen to desktop. So many amazing memories. Somehow, 1.3 looked so much better than 3.0. It's simplicity was majestic. 1.3 scheme was authoritative in my vintage opinion :)
My first guess is the -12 volts are missing. In later Amiga -12 V is used for serial and sound. But with the old A1000 it is probably the -5V line.
Indeed could have been the PSU -- wouldn't have really noticed any other issue without that rail. (Other than dead sound)
Hey Adrian, really like the leave the component alone it if it works philosophy.
Recapping needlessly annoys me for some reason
Me too. It seems to have become an obsession fuelled by youtubers to re-cap everything. Mostly when its not even needed. Yes check its ESR, but why replace if good.
@@g0bzy Well said. 😎👍
I had one of those with the signatures. I ordered the tech manuals and pre-ordered the Amiga and waited and waited. I learned C and C++ (cfront) programming on it with the Aztec compiler. Now I don't even remember what I did with it.
@2:17 There is a keyboard trick with the IIgs that on startup will show the names of everyone who worked on it.
I'm not so surprised that a shorted 40-year-old electrolytic cap was the ultimate fault... the surprising part is that none of the other ones failed first!
Yes, if there's a short and a 40 year old cap in the circuit I'd bet on the cap 10 times of 10. I generally always recap anything with old caps when doing repairs. All of them will fail eventually.
SPOILER ALERT!
Awesome repair work! Definitely some gremlins still kicking around.
Interesting timing as I was having the same issue with my amiga 1000. The floppy disc was working fine when I had the machine apart for cleaning and testing. However when I put the unit back together the floppy stopped loading discs! This is with a 1084s monitor. After some trial and error I could moved the monitor back about 4” and all was good again. Will either need to swap out monitors or look for a shielding plate as a long term fix
i was thinking the same. Floppies and em fields don't get along, no putting it next to a monitor or on top of a psu...
You could also use an audio signal tracer to check for sound at various points in the signal path, if one doesn’t have (the $$$ for) a scope! 😌
As long as you're just doing audio, you can buy a cheapo $5 sound "card" off eBay, and use that with free software _as_ a scope.
@@absalomdraconis Or even a pair of headphones, heh.
excellent
I miss Tillamook cheese SO much!
We need a "16 Bit Dance Party" music track.
January 2020 - pre-COVID (at least in the US). Those were the days!
that is why with Floppy disks always make back up or a data base of them hey Adrian !!
"Friends don't lie" about the Amiga 1000 shorted caps
nice job! thermal camera is nice for shorted components. i would add all three memory pieces and skip the top RF shield since no one uses RF shields anymore.
As a ham radio operator, I feel the need to send you some death glares ;)
(Okay realistically it wouldn't be noticeable between all the other cheap knock-off phone chargers and LED lights and ..)
I can use an AM radio down in the basement due to the LED lighting (and not just because it's the basement -- it's just buzz across the entire band LOL
When I saw the video title I instantly thought bad capacitor. I had one channel go on my A1200 and it was a capacitor. Commodore used polarised caps for audio instead of non-polarised and they fail. This one had leaked and it was SMD, I removed it and cleaned up the board but fitted non polarised through hole caps.
polarized caps is not the issue. and putting through hole caps will slooowly kill the pads of the boards of the stress... especially if you move it around..
putting in ceramics, tantals or throughhole caps is what I call a "recrap" instead of a recap.
As I mentioned in another reply, the A1200 just suffers from a bad type of relatively early SMD-electrolytics which ALL leak sooner or later. Polarised caps for audio is totally fine as long as you have enough positive bias.
aw, was hoping we'd get the little ditty that 1000s make when it runs that Kickstart bootstrap routine. Can't have it all, I suppose!
That's a low pass filter, to remove non-DC noise but any V+ rail noise/ripple is then fed into the opamp inputs to subtract the noise from the amplification (V+ noise - the input copy of the V+ noise = noise cancellation).
Ughhh original disk drives! I'm sucker for original hardware but man sometimes the juice isn't worth the squeeze. I took the original dd out of my A2000 and replaced it with a much newer modified pc floppy drive.
You could probably fully replace the daughter board with a pistorm