ZX Spectrum Part 2: Troubleshooting and fixing the ZX Spectrum
ฝัง
- เผยแพร่เมื่อ 14 ต.ค. 2024
- After nearly giving up on this old ZX Spectrum in the last video and an onslaught of comments, I decided to give the machine some attention and see what I could do.
Unboxing UK computers (intro to this machine:) • I visited the UK and b...
ZX Spectrum Part 1: • ZX Spectrum Part 1 - I...
ZX Spectrum Part 3: • ZX Spectrum Part 3 - R...
Time codes: (Spoilers ahead)
2:40 - How to fix the keyboard membrane
5:03 - Testing voltage rails
7:12 - Thermal imagine the main board
9:37 - Final RAM testing
11:20 - Adjusting issue 2 Spectrum pots
15:54 - Trying games
19:46 - The ZX printer
Never would have thought as a 14-year old back in 1981 I would ever watch a restauration video of my 'supercomputer' 37 years later....
...and never would have thought that more than 81.000 people would do the same...
@@klausstock8020 It's because the ZX Spectrum is... wait for it... legendary..!
Does anyone else remember borrowing school friends games and making copies on your twin tape deck in your bedroom, so you had about 20 games on a C90 cassette?
Obviously I never did it but I heard about it happening...
Me here in Portugal. Still have them. We share and copy. If I have 20 games and some friend have another 20 diferent games we share and each one become with 40 games. That started in the 80s with games and end up with DVDs in the 2000s :-)
We were way more advanced :) ...we used to send games via CB radio. As long as you had a strong signal and nobody tried jamming your signal it worked perfectly...good times. My buddy was 5 miles away and we often sent games over the CB internet.
@@hyperion8008 That is awesome!
We all had that one friend who was an only child and got all the latest games. So when they lent them to you for a night...
Nope. Had a disk drive for my Atari 800XL from the start. ;-) Actually, I'm pretty sure I did copy a few cassette games on our Amstrad hi-fi system but not very many. I amassed quite a collection of original cassettes. Original disks, though? Too expensive. So, yeah, 95% of my disk collection were copies.
See how happy you have made everyone in the comments.. That gives you an idea how important this tiny piece of ancient tech is! Great job on this!
I remember we had to constantly adjust the volume of the tape player and the read head on the tape, often spent longer getting it to load than actually playing!
Later models were actually pretty solid, and there were many modifcations to the various issue boards, both official and otherwise, to improve reliability
@@TheTurnipKing i don't know if there is a fix for the spectrum itself, but if the level isn't enough you can use a headphone preamp between the phone and the computer. get an inexpensive studio one for 20 bucks, eg a 4-output (or 4-input) one, and it'll be great.
btw, this wasn't the case here, but: when adjusting calibration pots, sometimes you have to replace the pot itself, because it itself will simply not hold the value that you put in!
That's my memory of loading programs. It was fingers crossed to see if it would actually load. Mostly it failed at the very end. As you say more time loading than playing.
The microdrives that came after were pretty reliable though.
@@petermferguson you're joking, the microdrives were notoriously unreliable
@@TheTurnipKing The +2 with built in cassette player was OK, but my 48k+ (plastic keyboard) struggled, but that might have been the Dixons brand bundled tape player that came with it!
ZX Spectrum's typically want a loud signal.. at least 2V p-p. Most phones cannot output a signal that loud. A small amplifier helps, or you can build an opamp circuit that works as a schmitt trigger and does the job even better. JoulesPerCouloumb goes into this in his "ZX Spectrum +2 Repair. (No. 7). Part 3" video. From the lines during loading, it looks like your phone is barely producing a loud enough signal
@@adriansdigitalbasement Looking at the schematics it looks as if Sinclair added a 2K7 pullup on pin 28 of the ULA to 5V. That would certainly bias the audio input a bit higher and make edge detection a bit better. You could always try that out.
The later Amstrad models with built in cassette decks used an opamp configured as a Schmitt trigger to produce a nice clean square wave for loading.They even touted this as "More reliable loading" on their models. It certainly does work - i've loaded games from a usb-stick type player running from a single 1.5V AAA cell using this circuit
You dont need an opamp to amplify a digital signal, just use a 555 runnimg at 5V or the cmos version at 3V, i have no idea about the ZX so whatever is more convinient. 555 are really good buffers, smittch triggers and even mosfet drivers, they are good for a lot of things. Why make a circuit when a 555 alone works? :D
@@laharl2kbecause its not a digital signal, its an analogue one which is being used with level triggering to produce a digital input.
Laharl Krichevskoy well some folks (like me) have hundreds of op amps in their spares case yet not a single 555 😀
The only two 555's ive got in my parts drawer came from school... 25 years ago ;)
Any opamp will work.. even the 741! (then again, the 4 of those I've got in my parts drawer ALSO came from school :)
Really glad you got this baby working, Adrian! As for the loading problems, I know all too well about them, being a modern-day Spectrum games developer, who targets real hardware vs. emulators, and takes pride in writing turbo loaders. Let me tell, you even Apple devices-which notoriously can supply up to 1.5 Vpp on their audio output jack-can give you problems. The Spectrum was designed to work with tape recorders from the 1980s, which could easily drive high-impedance headphones. Those could be anywhere from 150 to 300 Ohms or more. Compare that to the measly 16 Ohm earplugs of today. So you do need a decent headphone amplifier, something that can output around 3 Vpp or even more.
As for the low volume of the Speccy during a load, that is okay, albeit in your case, it’s a bit too extreme. Granted, most of us used our tape recorders as amplifiers, using the Speccy’s MIC (output) jack. You can simply feed it to an RCA audio input of your TV/monitor and leave it there.
As I mentioned before, it’s a good idea to replace a few electrolytic capacitors, especially around the power converter. It’s also advisable to add a few 1µF multilayer ceramic caps to the lower RAM chips to clean up the 12V rail. You can either replace the ones on the board, or just piggy-back them.
Ast A. Moore Is
c46 is the critical one, if it goes low capacity, the -5v line drops and can make the lower ram fry, others can usually be left alone, maybe replace the reset cap, as if that drops, it may not 'boot' except after a few goes, its the same type as c46, personally i'd fit a non electrolytic type, should never fail..
I’m happy to see that you didn’t give up on it. Turned out great with some effort and little cost.
It's always great to see a broken machine restored to its former glory. The spectrum was such an iconic machine for us Brits in the UK, especially for people my age. I had the later Spectrum 128K +2 from Amstrad as my first ever computer when I was just a kid. But that thing taught me how computers work, how to program, and was the starting pistol for my career in IT. So yeah they may not have been the best computers ever., but my parents would never have afforded anything else, and therefor, for a lot of us, they have sentimental value.
Don't you mean the Amstrad CPC? Hmm, just searched, apparently there was a Spectrum 128 but that was still Sinclair, Amstrad made the Spectrum +2, +2A, 2B, 3 and 3B. I do remember Amstrad licensing the name at one point but they just look like modified CPC models. I remember the game range for the CPC being crap cos most developers made games for the Spectrum or Commodore models (Vic 32 and 64)
@@P5YcHoKiLLa a 128 was a plus 2 numb nuts. If he meant a cpc he would have said that don't you think? It was a spectrum but the company belonged to amatrad by then...
Yes, you should hear the loading sound from the beeper. However, issue 2 is using 200 ohm beeper (other issues use 40 ohm) so it's quieter than beepers in other Spectrums. Additionaly, your phone doesn't output high enough volume. Spectrums like really loud signal for loading (near or at the max volume on cassette decks). Phones can't achieve it like normal tape players/decks can. When the pilot tone is playing (before "Program: Blah blah" appears), adjust the volume so the thickness of red and cyan lines are equal.
The ZX81 and ZX Spectrum were a huge part of my childhood :) Used to love games like 'Jet Set Willy' and 'Manic Miner'.
I am so pleased I was there at the start of the IT revolution, everything was new and exciting
I'm 45 years now and man... How I wanted to know just half of what I've learned in this video of yours... Some 30 years ago!
Thank you and greetings from Portugal.
Adrian, I'm proud of you :)
As for the ZX Printer - don't get your hopes up. Those belts are not available for sale. You can get your printer serviced and have a new one installed though. Reason for that: the R&D and manufacturing costs of producing a replacement belt was quite high and therefor the people producing this want to earn back their investment. I don't blame them: in the past 30 years no one was able to do this properly.
I had bought a ZX Printer 2 or 3 years ago and the belt was still in perfect order: flexible and clean. But hooking it up to my Spectrum, it made the computer crash. So I suspect that early in its life, the printer (or rather its ULA) was broken and the printer was never used since, hence the belt's excellent state.
I sent the printer to the company to aid them in their development of the perfect belt and many _many_ months later I received my printer back, still working.
Turned out my belt had given it's life for a good cause; it had been sacrificed to help everyone out there with a broken belt to get a new working belt again :D
Marc Kloosterman these days you can just 3d print a new belt the semi rigid filaments are very good. Ive even made rc buggy tyres.
It used to stink of burning when printing anyhow, no great loss!
On my original ZX printer (which I still have!) one of the two metal stylus wires failed, so I bent up a new one using a scrap of wire. Worked fine. I haven't run it for 30 years though, so the belt might have perished in the meantime.
I bought the 16K version. I loved it and even wrote my own simple accounts program in Basic for a small business. Served me well for quite a long time. It was a marvel at that time and affordable for the masses.
Yes, getting the volume *spot on* was always a thing with those machines.
And tweaking the height of the tape head with the screwdriver!
amstrad of course fixed it with +2 :) no more messing with volume controls.
My brother had one of these and this video really takes me back to the early eighties. Our neighbour also had one of these and he had the printer too. I remember it being top line tech at the time. I remember one game my brother had - Daley Thompson’s Decathlon. You had to use your forefingers of both hands to alternatively press the keys to get the athlete to run and then release the keys at the right time for him to jump. The times I had cramp in my hands, as well as really sore fingers is an oddly fond memory. I have watched this and your previous videos on this restoration with a warm fuzzy feeling, remembering how much I actually loved this computer. Great times!!
Nice work. You know that when you fix a vintage computer an angel gets his wings ;). My first computer bought it in August of 1984. You should build a Tapeduino for it for classic loading of games or buy a DivIDE for fast loading.
Great to see this working! I must say, for your first Spectrum repair you've done everything by the book :) Some points of note - (a) The easiest way of adjusting the color settings on VR1 and VR2 is simply to scope the composite output signal, and adjust VR1/VR2 to minimise the noise on the output. (b) Regarding the ZX Printer, the belts *all* break. Replacements are being worked on, and hopefully should be available shortly.
That's awesome to see it back up and running. One of my earliest gaming memories was Elite on the 48k, a game I now play on my Xbox
The one thing I will say about the lower voltage for the PSU, is that you may struggle to power any peripherals that you hang off the edge connector on the back of the machine. If you're not planning on plugging anything else in (and your printer is certainly not ready for this!) then you'll be fine.
Loving the series by the way!
I agree that you're completely correct that the volume isn't nearly loud enough for the Speccy to load. The volume of what is going into the computer from a phone or tape recorder should be easily audible through the speaker when loading. The red/cyan border lines displayed on the few second leader bit of loading each file give an indication that the volume isn't quite right, as the red and cyan bars should be more or less the exact same thickness. When one of the colour bars isn't quite as thick as the other, or drops out intermittantly to a solid border, then the computer is struggling to pick out the incoming audio. Once the volume is set to a good level, the Spectrum loading is quite reliable and forgiving of slightly different tape speeds and wow/flutter. Congratulations for saving the Spectrum, by the way. If in future, the keyboard membrane wears out (which they often do), these have been remanufactured and are easily and cheaply available for the rubber keyed model of Spectrum.
I built a little NE5532 stereo preamp with two 9V batteries for +/- and a 3.5mm input jack and a 3.5mm output jack to use between the phone and computer. The signal only needed to be about 50mv higher than the phone output for consistant successful loading. I measured the output of my cassetteplayer and that verified my findings. Great videos
I remember spending all week typing code from magazines into mine only to find it didn't work!
And don't get me started on the Hobbit game for the Spectrum. What a nightmare!
Hello. I only had mine during 2 years.... That was between 1984 and 1986. It's now 2022. And I still feel "home" whenever I see a ZX Spectrum 48K.
Loved my ZX spectrum spent all my after school time playing games, such a great computer. Good times
My youngsters grew up with the sound of network traffic and later gained a grounding in basic, way before their teachers some years later, had even thought that kids could learn a computer language and the fact they had a network at home was mind blowing . I've never had a phone to work at anything less than 100% volume in the same sort of situation. The volume was ideal for sound mad children and sensitive mothers.
Great job =D Always nice to see a Spectrum saved! You can buy replacement membranes btw! They can sometimes work when you trim the end off like you did, but often the traces in them just oxidize so much you lose connectivity and it cannot be repaired. You can also get replacement facias (and cases) of different colours too!
Ah, tape loading error, such happy memories, and yes, it did make a noise. Now you need Jet Set Willy, Manic Miner andLemmings.
OMG I remember Jet Set Willy and Manic Miner. I’m 52 now and this machine and these games take me right back to being a teenager. I swear, just thinking about Daley Thompson’s Decathlon makes my fingers cramp up lol
@@amandawright1372 Hah, and don't forget the seminal Cannon Fodder, Sensi Soccer and Worms!
Don't forget Horace goes Skiing
And Hungry Horace
I'm watching your old videos, Adrian. Loved your comment about the printer at 20:26 "It's really dirty to touch. I'm just gonna throw all this in a plastic bag and... not look at it again." Cannot blame you at all there. Glad you bagged-and-tagged it. But I could tell you absolutely hated touching it. Kudos for powering through it (despite your hands having been just washed...) But your comment made me chuckle. Great vid as always!
I remember a short machine code, about to bytes, program that allowed you to make a working copy of your own games via your spectrum. The tape loading “copy Protection”of a timed gap in the loading sequence was removed too. Local shops also started selling C30 tapes, so you could get a program on each “side”. The sound output was a very small speaker with little or no amplification, the output varied between spectrums. There was also a copying dongle, it fitted on the output edge connectors. I don’t remember how good they were.
Wow. This was my first computer. My brother and I used to play Renegade and the Untouchables forever. Operation Wolf too... and of course, Lode Runner and Dizzy Egg.
The buttons for most Speccy games were QAOP(SPACE) > up/down/left/right/action.
This was well-known in the UK until the days of WASD.
Just found your channel - thanks for the interesting vids! Subscribed!
As a 35 year old Brit whose computing experiences early on always consisted of what my family could afford from Car Boot Sales (the UK equivalent of yard sales, from what I can gather - 6am starts in a school sports field with families offloading whatever they could from the boot of their car - what Americans call the trunk) my first computer was a 128k ZX Spectrum +2A, one of the later revisions after the company had been bought by Amstrad, which featured a built-in tapedeck - this is the company set up by Lord Alan Sugar, of the Apprentice fame - our version of Donald Trump, though thankfully never given the keys to nuclear missiles. I am continually upset that my own Spectrum and my massive library of tape-based games disappeared into the ether. It gives me an enormous amount of pleasure to see you have revived this gem of my youth. Excellent work!
When I was a student in the UK back in the 80s, I had a 48K Spectrum + Microdrives (still got it and working). There used to be libraries advertised in the computer magazines for renting games and costs around 2-3 pounds for 1 to 3 days. That's where I got my games from.
I really enjoy old computers and I am almost 60.
Good videos.
Some great insights here. I have an old 48k Speccy. It's modded to output composite video via a secondary video out lead and also has a reset button added to the case. Although I've owned the machine for nearly 30 years (my gf now wife gave me it - I'd sold mine years before) I don't have a tape deck anymore and I failed to load anything via phone. The video offers the explanation I've been looking for. I will dig it out and have another go at loading with some form of amplifier assistance. Thanks. I got my first spectrum in '83, a Spectrum+ in '84 and a Spectrum 128 in '86. Tape loading was always a nightmare and it made learning to program anything meaningful difficult as you never really knew if your masterpiece had saved properly either.
Great to see the insides of the old spectrum.I had the zx81,spectrum 16k,48k,+2 and +3 diskdrive versions,the original 48k which was always breaking down and took like 6 weeks to get fixed.I remember the many long happy days spent with my friends waiting for hours and days loading games which would then error right at the end,so annoying or programming in games for days on end from magazines that then wouldnt work but when they did it was amazing.A lot of the taped games were so high pitched to try and prevent copying which i definately never ever did with my friends.My first 48 k went wrong so often that the shop eventually gave me a cheap upgrade to the +2 version when that became available.Kids today have no idea,lol
I had my speccy sound input cables attached to a midi hi-fi unit and had the equalizer settings just right so that almost every game worked (and yeah...double tape deck on it so I could run off a few backup copies of games, just in case)...Ahhh the halcyon days of my youth. Thanks for taking me back a few years Adrian.
That computer in the background just gave me many memories. in 1993 we had one of those with an MFM hard drive we upgraded to an IDE hard drive. Its one of the best memories i have with my twin.
When I had a speccy many years ago, I remember using tape players with tone controls also, if it didn't load we would try a different volume and tone, almost part of the fun but at the time very frustrating because they always got to the end and crashed!!!!! Oh what joy when block loaders came out you could just rewind adjust and go again without crashing.
Thank you for bringing back the memories
It's wonderful to see a little Speccy brought back to full health. I hope you enjoy it as much as I enjoy mine!
My Spectrum was my first love ❤
Robert O'Neill , mine, too.
MANY GEEKS FANTASY !!
I dumped my girlfriend when I got my spectrum!
Thank you for sharing this!!! The Spectrum and BBC were my first exposure to computer and it's wonderful to see someone keeping these old classics alive.
I never had or even saw one of these when I was young, but videos like this make me feel nostalgia - how can that be?
Thanks for the interesting video. The 48k ZX Spectrum was my first computer, which gave me several years of pleasure in the mid 1980s playing games and trying (mostly unsuccessfully) to write them. To confirm a couple of points - yes, you could easily hear the audio when loading a game and yes, the printer worked using a kind of silver coloured paper with electric sparks that burned text / images into it.
“R Tape loading error” was quite common, especially if you were using an audio cassette player with the volume set insufficiently low, you knocked the cable or heads on the audio cassette player were dirty and needed cleaning with a cleaning kit / cleaning cassette. It was very annoying if it happened at the end of a 5 minute game load!
I remember this old printer and the special paper with metallic surface. was going to write the same about the short circuit-printing process :-)
Sinclair launching the UK Home computer craze almost singlehandedly, From kits you built yourself to fully working home computers Its how I and many others got started In the UK.
Just beautiful seeing the games of my youth again. I had an Ohio 6502 Superboard II in 1980 (which I still have to this day) which was later cloned as the UK101 but some of friends my were ZX81 users. As a kid many arguments about which was a real computer and of course it was the Ohio SBII... LOL Thanks
THANK YOU!!. I´m from Argentina and this was my child´s first Computer, I have so many memories with it. I still have it and had the same problem with that flex cable and now I know how to fix it. Thank you for dedicate time to fix it.
Another Speccy saved from an early trip to Silicon Heaven. Good video.
But now, all the little calculators in Silicon Heaven are lonely, and have no games to play. :(
Just stumbled across your channel. Great to see these 2 classic British home computers restored to life. I spent many happy days learning to program basic on a ZX81 before moving up briefly to a 48k Spectrum and then onto an Acorn Electron (a Model b in Acorns own case). You have to get the original Elite to play on those model B's though. Looking forward to seeing more restorations. :)
Cutting legs from THT chips is by far the best way to avoid damaging PCB traces, especially of you have access to replacement ICs
Great job getting it working. Try to get games from “Ultimate”, they were legendary on the Spectrum.
Ultimate are my fav software producer......& they still are, 'Sea Of Thieves' is from the same studio & is a GREAT game today!
11:43 I just love the use of a crocodile clip and pointy screwdrivery thing to take a measurement :)
Nostalgia alert! I was given a 48K Spectrum as a leaving present from my gap year job at Logica when going off to university to ultimately study Computer Science... oh man... that was a long time ago but the start of a very fun and varied career. Thanks!
Ah, the fun I used to have using Logica's Rapport database from COBOL at around that time!
@@ctunnah Exciting times... including the Logica VTS 2200 word processor... if you have a spare 3hrs and want nostalgia overload try out theamphour.com/241-an-interview-with-chuck-peddle-re-air/
I never had trouble loading games into my issue 2 Spectrum, but I was loading from a Philips cassette recorder. The noise of the data was easily audible as it loaded too. Are you using a mono or stereo lead?
Great work on fixing that computer.
I'm sure others have said this, but that Speccy is actually in pretty good shape compared to most. A heavily used Spectrum took a real battering and would often be falling apart (but still working)
yeah he was lucky the keyboard membrane wasnt f##ked !!
"...this computer give an INSANE AMOUNT OF JOY TO SO MANY PEOPLE...I totally agree! I was one of them!! The orange book on the left was my "way in door" , first source of joy in computer programming, and let me introduce into the realm of the ASSEMBLY language!
Sinclair ZX Spectrum...GREAT MACHINE !!!
even the latest QL didn't match (even thou way more capable) the characteristics and the versatility of the ZX Spectrum!
+Adrian Black
I love restoration video's, and this one was very cool! I think you did a great job restoring to working order what was effectively a trashed system. Well nice this!
The micro that introduced the IT to a whole generation in my country. A real best seller.
thrilled to see you get this up and running this side of the pond. I have a couple of Speccys, but have never been brave enough to attempt firing them up. Time to do some more research and maybe try to relive my youth :-)
Cutting off the chip is actually a preferred method we used to teach in the Navy if you dont care about the component being removed. It protects the board from heat. We would emphasize using diagonal flush cutting pliers making sure you dont transfer shock to the board in the process. It works well for high lead count surface mount components also like plcc packages. On a surface mount, to get the leads off the board after you cut off the component you can just load a half conical tip with a fresh solder ball and run to over the leads and it will pick them up in the solder.
Interesting -- and I can see why it's recommended. Lots of people complain when I do this though as the part isn't always bad -- and then I'm "ruined" a good vintage part.
Regarding the loading issues. The ZX was designed to use a mono jack but is wired a little weird as it has ground wired to the right channel. This does cause some issues when loading using a stereo jack as the two channels will cancel each other out. To fix this, many sound files has the “normal” signal in the left channel and an inverse signal in the right channel. This also doubles the amplitude of the signal and might help too. Try to check and see how the two channels are recorded in the sound channels you are using.
Adrian Black I had some issues with a normal stereo to mono cable as well. I have created a small stereo to Sinclair mono adapter and this works really well.
MsMadLemon talks about this issue in one of her videos: th-cam.com/video/0UgdkQDqA-A/w-d-xo.html
The loading border of yellow and blue lines is normal. The tape volume was never a great issue. Once you got it right it remained stable. The only addon I ever used was the Kempston joystick connector.
I had several years of consistent usage of the machine. That fluid fluttering noise it made while running is one of the most powerful memories of using it. By the time my technical book collection overseeing aspects such as machine code/assembly programming amounted to anything, the machine had had its day. It more or less remained a black box for me throughout the 3 to 4 years in which it reigned supreme, even though I must have learned something. Mine was certainly reliable. I only ever used the single power supply that came with it, although the Kempston interface edge connector gradually became worn from multiple insertions and ejections of the unit. I had to be careful how much pressure to apply to the keyboard because the Kempston interface jutted down to the flat surface on which the whole machine rested at its rear, so that any downward pressure would cause up and down rocking around the edge connector and the making and breaking of individual contacts would have an effect on the operational qualities of the machine, such as causing it to revert to the boot screen and such like - so I had to be careful not to upset it too much while using it.
One of my favorite books I revert to more often than any other is George Dyson's, Turing's Cathedral, about Von Neumann and the Princeton MANIAC machine, which eventually gave rise to the typical VN architecture of which the humble Speccy is but a carbon copy. The MANIAC only had 5k of memory. I would come to read about Turing Machines and the like only much later, so the full significance of what it was that I had in my hands only clicked well after the event of the ZX Spectrum, which I still keep in its original box.
Outstanding vid. Takes me back to when we traded in our zx81 for a 16K Specy. Ah, the good old days when programming was programming... I also admire your soldering skills. I would have been completely lost...
I recognize that thin sticky tape. It certainly could be factory-issue. It was in a lot of products with thin metal panels, most seemed more 70s than 80s.
I wonder if my ZX81 membrane leads needed trimming too. My older friend who'd previously owned them was convinced the leads had cracked, but honestly, cracking didn't seem to fit how they went wrong.
Yay! It works! Nice it had adjustments on-board.
Jet Set Willy! I liked that game a little too much, especially as I could only play it at a friend's house... :)
A 3 minute load time! ZX81 games tended to run to 7 minutes, resulting in near-terminal cases of boredom! XD Atari games tended to be 5 minutes which felt quicker by comparison, but I was a little older.
"I'm just going to throw all this into a plastic bag and not look at it again" is what happened to my ZX81s, and they weren't even dirty! XD But I can imagine that band getting dirty from the burning process. What kind of soot would you get from aluminium-loaded paper? I don't think I'd want to handle it because aluminium is associated with alzheimers and sometimes metal compounds are much more easily absorbed than purer forms.
The 7805 was rated for 7V to 12V input if I remember right.
I love the style of the Spectrum's power brick. That totally unnecessary kick-up at one end was... I don't know, just part of the sci-fi-ness of the era. XD
As you've no doubt discovered, very few Spectrum games tell you the controls on screen, you're expected to have read the tape inlay/instructions. In addition to tape images of the many games themselves, the archive at World of Spectrum (www.worldofspectrum.org/archive.html) also has instructions and inlays for virtually every commercial game released (including those where they don't have permission to distribute the tape images themselves, only the accompanying material).
You'll also find the copy protection codes for Jet Set Willy, which you'll need if you ever get it to load :-)
I recall from my brothers a spectrum back in the day that even a completely working spectrum with a good casett player would fail in loading randomly and take multiple retry's to get it to load. I was only a child, but for me it was part of the experience of owning a spectrum :).
Yes, part of the Authentic ZX Spectrum experience! Pray that there is no R Tape Loading Error. Tweak volume levels, try again, repeat! Some games would load most of the time, and some would hardly ever load. Oh the excitement!
Ahh yes. It was like a kind of gambling and when it loaded you felt special! lol.
I remember there was one game I only ever got to load one time, and it became legend.
Especially loading Skool Daze
@@DaveMcGarry lol yeah. I think I played that game once and when it loaded I was shocked. Probably why I have epic memories of the game lol.
Back in the day, we had to use portable cassette recorders. The ear and mic where connected (2 in 1 and 1 in the other) and then we changed them when the game was loaded. We played the sound through the cassette recorder. Volume while loading was crucial and was the 1st thing adjusted if a game failed to load. There was a sweet spot at maybe 75% which worked for most original games.
Hi Adrian, as others have said, the problems with the Spectrum crashing whilst loading is likely to be because your phone isn't loud enough to load the software correctly - this is also the reason you can barely hear the software loading.
The loading sounds should be as loud as the beeps you hear when the diagnostics program started.Also, you should use a mono to mono lead, stereo cables may be producing an insufficient source for the Speccy to read.Great work, by the way! Awesome to see one of these machines repaired across the pond!
Back in Poland we used to lovingly call it spektrumna - trumna being the Polish word for "coffin".
Use "Treasure Island Dizzy" as your test program. It loads pretty quickly and has nice music and starts with sampled speech. Great game too, perfect for showcasing the 48k Speccy at it's best.
Thanks for saving the Spectrum, always wanted one and ended up buying a VIC 20 because I could afford it as a used one when I was 13. I have to confess, that I am a bit jealous!
Brings back lots of memories, well done for fixing and preserving these machines, thats a time consuming hobby you have there
My first computer was the ZX Spectrum 16x, had great fun typing in code for games from magazines.
So nice to see the Spectrum working, brings back many memories. Now I think i'll go and watch 'Mirco Men' again since it is such a good dramatization of the two machines you got ( BBC Micro and Spectrum )
God for such a small channel I always look forward to watching your videos
Yeah, the old Spectrum printer sparking away - cool thing to watch in a darkened room, BTW. I later switched to a Timex printer, which used thermal paper. That was much better. Later, an LPRINT4 Centronics interface with a Star SG-1 (yeah, I threw some money at it). BTW, these video adjustments were gone with Issue 3. Bad luck you got an Issue 2.
A friend of mine threw out the entire power transformation circuitry and made separate lines for 9V, 5V and 12V. The original 9V powerbrick fed the 9V lines only. It was quite a box I needed to feed power to my Spec - but then again, I had quite an array of peripherals hanging to that poor beast: printer IF, diskdrive IF, joystick IF, color monitor IF, tape cracking IF. It must have been one of the most expensive Spectrum configurations in Holland at the time, around $2500 in 1980-ies money, which would be close to $7500 in todays money.
Holy smokes! I had one of those NAP green monitors connected to my TS2068 in the 80s. That monitor was a tank. It fell down a flight of stairs and still worked fine.
Loved my Specci. Loading pirated games was so painful though, Had a low-tech solution for the various volume needs. I cut and filed multiple wooden wedges to block the volume slider of the tape recorder in different positions depending on the game loading. Half a Millimeter made a world of difference!
Double side tape from factory, I stuck 1000's of those on..when I worked with them
What a nice video, thanks for doing this. I got my 16k Spectrum for Christmas in 1982, can't remember when I got the 48k model. It'll be up in my loft right now sitting inside a DK-Tronics keyboard, bet it doesn't work.
You definitely should be hearing the game loading so I would say your volume isn't loud enough.
Would spend a whole weekend programming the Speccie with my Dad, there would be a poster on one side and the code on the other. Between printing and our typing errors, they would very rarely work. Was the best time ever. I still have the unit with a whole box of games in the loft.
Impressive.I remember the 48K and the Timex Sinclair 2068, the silver gray one, wich had a cartridge to emulate the Spectrum.You made me want to go back to my mother's house and fire up my 128K, which I stored in the original box with the original documentation!
I remember having to remove the mic lead when loading, and the ear lead when saving. Apparently, they create a feedback loop that interferes with load/save performance. Used to have to wind the treble up too. HTH
To loosen two-side glue I use Kontakt WL spray. But as it's mostly isopropyl alcohol, I think that does the job getting the glue loose. I've removed the keyboard connectors from the PCB and glued them to the bottom of the top cover fixing the foil cables stable in it, then wired the connections to the PCB by ribbon cables, using IC sockets. Fixes keyboard foil connection problems for ever.
This video was in my TH-cam recommended page...
Please be careful with using a small switching supply, for your Spectrum computer.
Small switching power supplies are notorious for AC-ripple on the supplies. Good ones have a large amount of capacitance to ground, passing in series through an inductor. This LC-Tank will get rid of the AC-ripple. You may want to do that with the unit coming into your shop.
I'm a licensed HAM radio operator. None of us will use switching power supplies, unless they are known to contain proper filtering. Noise in radio, is much more of a hassle than in digital (you have to listen to the noise). But you get the idea. You don't like ripple, so take the proper precautions, and be careful of ripple.
Have fun and good luck!
PS> I used to have Timex-Sinclair 1000, and it got me started in computing... many moons ago !
One good thing about the printer (it's called a spark-gap printer) is the paper roll is exactly the width of an audio cassette case - perfect for making your own tape inlays. I must dig my old kit out, sadly the UPS I built for mine got thrown out (I built it into a custom desk tidy that had space for cassettes - I only wish I had taken pictures of it!)
I loved my Zx spectrum, had the 16k version & upgraded to 48k with a 32k rampack that you plugged into the cartridge slot. Bought this back in 1982/83 & it did me well until I upgraded to a CBM64 some years later
Superb. I swapped my Tandy trs 80II for a MK1 16k spectrum. Bought a 32k ram expansion pack, but this had a key in it and my edge connector didnt. So at the ripe old age of 11, I modded the main board with a hacksaw blade and nail file to get my ram expansion to fit!!!!
Wow that was daring considering how much the stuff cost back then!
I'm not surprised you had so many failed RAM chips when you consider that they were actually bad 64s to begin with when Sir Clive bought them at a bargain basement price.
Yeah, I was going to say that.
These chips were already "half failed" when they were first installed, and they've clearly gone "full failure" in the intervening time.
That was the first home computer I saw in my teenage years in the 80. As for the memory chips, I remember putting together new PC 486 in the 90's. I had some problems with booting and windows installation. I replaced 2 memory sticks. Again the same problem. After replacing another sticks (total 6), I decided to change the motherboard and a processor from Pentium to AMD. Still the same problem. Finally I bought another memory sticks from a different shop. And they finally worked...so I tried I think 8 different new memory sticks before I got it to work...
I bought my first motorcycle with the proceeds of selling a spectrum game. Not in the same league as Matt Smith (Manic Miner, Jet Set Willy) , who (famously) bought a Jaguar that he wasn't even old enough to drive. So I have fond memories of them. Mine ended up with a dead keyboard, so the mainboard was installed in an old terminal keyboard case I found, but I never could make it work properly. (It turned out the other keyboard had capacitive keys). I think I probably gave up and threw it away. All I have left now from those days is a production copy of my game that I bought on eBay for nostalgia's sake.
16:55 tip to set up the volume is to estabilish a pilot tone, and see that cyan and red stripes have same width. Red of yours are thinner a bit, so levels aren't optimal.
I've always liked the minimalist engineering in the ZX printer. You have one DC motor, one output bit and one input bit. The one input bit is pulsed as the stylus passes the start of the page. The CPU is in a tight loop with interrupts disabled shifting data out to the one output bit controlling the stylus spark.
Atari did something very similar with their SLM804/SLM65 laser printesr. The printer was almost completely dumb - it had a small FIFO. The ST driving the printer assembled a bitmap in memory and sent it out via a DMA over ACSI (a ruthlessly cost engineered subset of SCSI) to the printer where they filled up a FIFO. The FIFO emptied into printer engine's data input.
In fact modern printers are probably a bit like this - you have a very lightweight page description language which is really just about sending bitmaps generated on the host machine to the printer hardware.
I.e. the days of using Postscript have largely disappeared. Of course unlike in the ZX printer days microcontrollers are cheap. So you can still have ST Laser printer-like levels of intelligence - i.e. a FIFO. So like an Atari ST, but unlike a ZX Spectrum, a modern machine doesn't have to sit in a timing critical loop with interrupts disabled. All it has to do is make sure the FIFO doesn't empty.
@Lassi Kinnunen My point is that a dumb printer is going to be faster than a smart one. Make a bitmap on the computer and stream it to the printer. The printer doesn't even need to have enough ram to buffer a page, just enough to have a FIFO big enough to keep the mechanism running if interrupt latency stops the host sending data.
Certainly Brother laser printers and HP inkjets seem to work like this - they both have a "lighweight page description language" which not publicly documented but is probably just a zlib compressed bitmap. GDI printers pioneered this technique on Windows.
It's a far cry from Postscript where you send a Turing complete language which needed to be generated on the host and then rasterised on the printer. And you need to license code from Adobe!
Glad you got it working! I had a later model (after Sinclair had been bought out by Amstrad) called a Plus 2 which had a proper keyboard, built-in tape deck, better I/O including built-in joystick ports, and 128K RAM, still compatible with all the 48K games. Apart from the RAM I don't think it was much different or more powerful in other areas, except for the audio which was better in 128K compatible games. I might be wrong but I think it had a better sound chip with more voices.
A mod for the ZX spectrum PSU (or ZX81/ZX80). Fit a 240v VDR across the 240v power lines. I used to do this inside the UK power plug but it's possible to do inside the PSU case. This prevented crashes due to power surges. I used to be annoyed after a couple of hours coding it crashed due to my mum powering on the vacuum cleaner! It also improved tape loading success but the main reason my stuff nearly always loaded was due to loading from a BBC micro tape recorder normally used with the BBC micro. If you have one of these, then check audio out at full volume and compare with your smartphone). I would play the cassettes over CB radio and my mates could load them, 80's wifi!
The proportions of the red/cyan bars when you have the leader tone give you an indication of the correct volume - you want to adjust the volume until the red and cyan bars are an equal width. None of my phones generate a loud enough signal for speccies - but as it's just squaring up the signal anyway internally, you don't need a terribly high fidelity amplifier to get something usable.
The ZX Printer was an unrepairable device until recently - Ian at Mutant Caterpillar Games was able to get replacement belts manufactured and offers a repair service now.
For the PSU - the PSU is specced as unregulated 8.5-11V IIRC. Yes, the 7805 is a big heat source, so it's a common mod to replace it with a Traco 1-2450 smitchmode module, which is pin for pin compatible with the 7805, but runs much, much cooler.
What a pleasure to watch. It's so nostalgic for me. I also got inspired to try something here similar to your cable solution.
ZX81's And Spectrums were a bit deaf, The volume setting for the standard japanese cassette recorder of the time was full volume and then down about 10%. To be as loud as possible without the distortion at full volume. It was hit or miss with whatever tape deck you were using until you got it right then it was fairly solid. Glad mine and others advice about snipping the ribbon connector worked.
Great video, back in the day loading and crashing was generally because the tape deck volume wasn't high enough, so the program loads with corruption.
Great it works! I would swap 7805 with drop in 5V DC/DC converter. It will not run hot and leaves some cool air to ULA.
my first computer was a spectrum 48 . best game on it was Horace goes SKiing until i got Deathchase . then i was a tree dodging fool ....
Oh, Horace! I loved jet-pack.