I owned a ZX81 , and my school mate who I hung about with in the day had a Spectrum 48k , although I never got one myself. I ended up getting a Dragon 32. Wish I had kept them all :) Really loved the Speccy, it had some iconic games (Manic miner, jet set willy etc...)
I had the MSX first, my friends at the time had commodores and I don't think any of us had the speccy. It does have a long list of classic games. I've got a few tapes here to try, just need to fix the system first.
It was just a bit before my time. My first micro was the MSX but that didn't come until late 80s and was a hand me down from my cousin. Despite the grey hair I'm only 41 lol. But, I'm looking forward to getting this one working and finally having a chance to play with the system for myself.
Welcome to the club. Couple of things you might want to try. If you force a reset of the CPU by shorting out the capacitor on the reset line, if the CPU is working (or at least partially) you should see the patterns on the screen change. The other thing is if you'd rather not de-solder all the RAM, you can get hold of a diagnostic ROM, which should help identify which particular RAM IC (or ICs) are faulty. I'd also recommend taking a look at the channel JoulesPerCoulomb, who has a really good series on diagnosing spectrum faults.
Thanks for the tips, I've already removed all the ram and I think from some testing that all but 1 of the lower ram chips is faulty. I've ordered a complete new set and hopefully that gets it up and running. To test the CPU I may swap it out into one of my other systems that uses the Z80 but I'm fairly sure its working.
Excellent! I've watched these in reverse order lol - I had partly watched this before watching part 2. Just echoing my comment in part 2 - the transistor you used might not be up to the job. They all have different characteristcs related to current, voltage, gain etc.
Thanks for watching them in any order 😂 As I said in my response to your earlier comment I've since checked the datasheet and yeah it is a bit different. Need to order something more suitable before it blows taking out more ram.
If you don't like the rubber keyed Spectrum... you'd hate the ZX81! The size of the ZX Spectrum was decided by the size of the keys. The keys had to be a usable size, they worked out how many they needed and away they went. Rick Dickinson for the win! (Was he the brother of Bruce and David?) Fascinating stuff!
When I was at Uni in mid 70's I couldn't even afford a micro, despite getting a degree in Systems and Informational Science, so even a micro with a bad keyboard, was better than none.
I didn't pop my Speccy cherry until a couple of years back, having grown up with C64s and BBC Micros. Down here in Australia, the ZX Spectrum was an also-ran. The price of the 48K was too close to the C64, and the bottom end of the market was owned by the Dick Smith VZ200 (a rebadged VTech Laser 200 that was kinda like a ZX81 with colour). For what it is and what it set out to achieve, the Speccy is one of the all time greats. It's probably my favourite 8-bit machine to work on. This video is great too. :) BTW a new keyboard membrane will make all the difference... not that it'll magically turn the Speccy's keyboard into a C64's, but it'll reduce the frustration factor quite significantly.
My dad has one of these, it doesn't work now but for its time it was a great little machine. Unfortunately, IMHO it hasn't aged well compared to other machines from the same era. For those of you who don't know, a lot of the game developers in the UK started out coding on systems like this.
I know a lot of people are very fond of this little system and it certainly was the starting point for lots of people in the industry today. Hopefully your dad can get his one fixed :)
As a kid, I only had Spectrums. Never had a C64, Amstrad CPC, Amiga etc. Now that I'm a middle aged man with some disposable income, I have most of these! :-) I'm somewhat biased as I love the Spectrum (I had a +3 with the disk drive) but I will say that the Spectrum's CPU was quicker than other systems and it shows. Although the colour clash is annoying, I do appreciate the fluidity of games - and clarity of the graphics - compared to other systems.
My first micro was the MSX, yes and odd choice in the UK but it was a hand down from my cousin. After that it was a master system then straight into Amiga so most the popular 8 bit computers all passed me by. I remember a friend having a C128 and we played lots of 64 games on that. Hopefully I can repair this one and get to experience the colour clash for myself :)
@@CRG A great game to try out is Green Beret. Colour clash is minimised and the graphics are very detailed and very fluid. Compared to other systems, it's easily one of the best ports. It's very difficult though!
I still remember a review of the Spectrum when it first came out describing the feel of the keyboard as “pressing a piece of dead chicken”. I have thought of it as a dead chicken keyboard ever since.
My second job was with a company that repaired my ZX Spectrum back when I was at school. I didn't know it was repaired by them until I looked at the repair label on my Spectrum when I got back home after my first day there. (My first job was as an apprentice TV engineer.)
Have an old spectrum and from watching this video checking the same pins for measurements I have discorved the problem is with tr4/5 and lower ram , first class video now to order some parts , great video
The psu is not the original one for the rubber keyboard speccy. If I recall correctly that one is for the 128k version probably when Amstrad took over. Seeing this takes me back to my school days playing on the machine in my dinner hour, you had to be quick to get a machine. The fun of waiting 3 mins or so for the game to load from cassette , hoping it would not crash part way through. Classic games like Chaos, Jetpac, Elite, Daley Thompson decathlon, harrier attack, TLL, Cyclone, Quaztron and lots more. I recall learning to programming in assembly on these
@@CRG It's a Spectrum Plus PSU which should be 100% compatible with the rubber key machine. Even the +2 PSU would be fine, the +3/+2a PSU has a DIN plug on it so wouldn't fit...
As has been pointed out already, that PSU appeared with the 48K Plus machine: mine has one and it was also used for the 128K Plus "Toastrack" computer. Amstrad just rebranded the PSU for the 128K+2 which internally, is literally a Toastrack with a tape deck attached.
I love the Spectrum, had one back in the day when I sold my BBC. I have one now too that I built myself last year and has a DivMMC Future for loading games from sdcard. 2 seconds to load is way better than the old 3-5 mins haha. imo the ZX Spectrum is the greatest computer of the 80s (and I loved my C64 and Atari 800 too) and there are still new Spectrum games coming out even in 2022! The Spectrum scene is very strong right now.
A modern means of loading games is something I'll have to look at eventually so I'll look up that DivMMC you mentioned. For now though I'll just be happy to get it working and if I can I think it only right to load a few games the traditional way, even if it does take 3 minutes 😆
You can get voltage regulators that don't need the big heat sink now. Not tried them myself but apparently the heat from the heatsink makes the keyboard ribbons brittle.
Man I love your videos and all but I'm struggling to identify your accent. Mind you I'm born in Finland so...did you say "regurglradr" at 20:28? Because that made my day haha. Niceeeee. My beer just got foamier. Thank you for these excellent videos. Love from Sweden
I'm from Belfast, Northern Ireland and yes the accent can be a bit thick at times. I do try to slow down and speak more clearly but as my videos aren't scripted sometimes I forget myself. Your comment did make me laugh though, glad to hear you enjoy the videos 😁
Hmmmm I've seen a cap blow up like that....the case hit the bone of eye socket. Stupidly I had my head over it when it exploded.....now that was dumb. I've not done it since. Like the way you've incorporated another vid into your own 👍
Yeah, after a while I didn't even have to look at the keyboard most of the time. My fingers just knew what mode and combination of shifts and key were needed to get the token I was thinking of. It's the sort of skill you build up easily when you're a kid.
@@CRG For usual commands it's great. For words like "IN" and "OUT" they are a bit of a pain to get to (switch to extend mode, then symbol shift + I or O, IIRC).
Yeah I started programming on a VIC20, then moved to the Speccy Plus and by the time I'd moved on to a PC I'd got so used to the Sinclair tokenised basic that I actually resented having to type stuff in full!
I have 4 Spectrums of the first era (16k/48k) and none of them work. The design was clever but the execution had a lack of reliabilty. I built a brand new clone last year with more common chips and it works like a charm.
It was a very clever design, managed to achieve 90% of what the more expensive systems could do at a third the price in 1982. These design decisions eventually held it back but there was no arguing that it was the right balance of functionality and price in the early years! When you could get one of these for £175 or a C64 for £400, it was a no brainer in 1982.
Sinclair knew how rubbish the keyboard was for programming in BASIC, hence the shortcuts for many of the most used keywords. I never owned a Speccy back in the day, but most of my school friends did. I admired sone of the isometric games like Knight Lore - those programmers really knew how to get the best out of such limited hardware!
It was just a way to save ROM space to fit everything in. No need for a tokenizer if the input are already tokens. There is an interview with Steve Vickers explaining it all. He worked at Nine Inch Nails and wrote the manual and the floating point calculator routines. It had nothing to do with the keyboard.
Since each key was a whole command and included a space automatically you didn't really type on it anyway, you had to spend a few seconds searching for the command before pressing a key (or i did anyway) and if this was your first computer then it was ok. I've go a lot of love for these, even with the de@d flesh keys. Most people just hit J (for load) then "" then enter and hit play on the tape (kempston joystick in hand)
I think for the most part I'll just be loading tapes, need to get it working first though. New RAM is ordered and hopefully that's all it needs. Thanks for sharing though, I wasn't aware of the amount of built in commands. I sure it helped a lot back in the day.
Dude! You’ve flipped where you vid… liking the new set up! If this is an old set up and I’ve missed loads of vids! Soz! Stop slagging the space bar!! We all know it’s in the right place and has been in the wrong (s)p(l)ace since then! Ribbon cables!!! Careful!
Yeah I swapped things round when getting back into youtube a couple of months ago. Had a bit of a break for a while, had a lot of DIY to do. If you look back a bit there's a video tour of the new setup. I'm not slagging the space bar, it's just "uniquely positioned" on the speccy 😉 Always have to be careful around those ribbon cables 😂
I had a classic Speccy back in the day and the keyboard was terrible. But for most kids of the time that got one, their experience of a keyboard would likely be from a mechanical typewriter and the Speccy keyboard was much less work than one of those. Computers were only just beginning to appear in schools and most of the teachers probably knew as much (or as little) as the kids, so it was a couple of years before the kids really began to realise how bad the keyboard was. It does actually have a lot in common with the cheaper keyboards on the market today (and most laptop keyboards too), using a plastic switch membrane. That said, the "dead flesh" keyboard became a running joke and later a point of nostalgia for Speccy fans.
Thought you would have went for a more modern voltage reg... and Do away with the heat sink. Protek Switchable Joystick Interface (for Protek, Kempston & Sinclair).
Just handier to use what I had in stock. I should order a handful of those modern regulators since as you say they run cool. Thanks for letting me know on the joystick interface. I found a manual for it online and I've been told for most things to just leave it set to kempston.
Simplest way? ULA is probably working, because it generates some picture. You had bad TR4,so DRAM 4116 is almost sure bad too. Remove them ALL, then replace it by sockets and then carefully test one by one. Best way how to do it is Retroleum diag ROM. Remove original ROM, replace it by socket, add OR gate between /MREQ and /ROMCS and EPROM input pin 20. Retroleum diag ROM will diagnose VRAM first, bad ones will signalise as border colors. So even computer without any DRAM 4116 will do something. At a same time, if Retroleum diag ROM will do something you will know, Z80 is at least partially ok. Still can have bad /M1 input, but even without it BASIC should works. Only additional peripheals will not.
@@CRG You don't need buy anything. You can just download it and program your own EPROM 27C128. Retroleum interface is needed only if you want it as external device. But you have computer where is ROM maybe damaged (didn't you said it is warm?), so it is safer replace it with EPROM and diagnose other coponents first - ULA, RAM, Z80 and after that verify original ROM. External interface allows verify content of internal ROM. Which is good, but sometimes damaged chip can have infuence on data & address BUS so it is much more better just remove suspicious chip. And ROM in sockets allows use other custom ROMs which can be useful in future too.
It's a system that I've seen lots of but genuinely never touched before this video. It certainly has a budget feel compared to its peers of the time but since I've now got most of them, well, I thought it time to try a speccy. Thanks for watching, hopefully I can get it finished in the next part :)
The power brick were rubbish and put as much as 13v into the spectrum when working on them you need a regulated 9v bench supply, the 13v blows the inverter which provides the plus and minus 12 volts for the memory, this in turn blows the memory leaving you with a very dead spectrum.
Yes I'm sure the membrane only keyboard was a nightmare to type on. At the end of the second video on this machine I do type in the classic hello world program (all 2 lines of it) but I must say the keyboard shortcut thing really helps.
