Interesting video. Always good to see a ZX81 brought back to life. It was my first computer on which I learnt to program in BASIC, then Z80 machine code. :)
@ezContents
2 жыл бұрын
Thank you, Chris! It was a pleasure to work on it and fix it.
@akrimpen2
2 жыл бұрын
For some reason I find it very pleasant to watch/listen to your video's while working. Keep'm coming!
@ezContents
2 жыл бұрын
Thanks Arjan! I am very glad to hear that. 😊
@SqueekyBums
Жыл бұрын
Iconic machine. I still have mine, and the ZX80 which introduced me to my first home computer. 👍
@ezContents
Жыл бұрын
Indeed. I wish it was my first machine. My first baby steps were on ZX spectrum.
@MoreFunMakingIt
2 жыл бұрын
Superb! I love that you just build your own testers. I have used a composite mod with backporch on one of my ZX81's. I will link it on twitter for you. Looking forward to more videos :D
@ezContents
2 жыл бұрын
Thanks Lee! I had to keep myself busy while awaiting the ULA replacement.🙂
@leesmithsworkshop
2 жыл бұрын
@@ezContents I was just talking to other lee about building a Z80 tester for a spectrum 48k I have and then he told me about your new video.
@ezContents
2 жыл бұрын
@@leesmithsworkshop Cool! Check the link in the description for details.
@oldblokeh
11 ай бұрын
Just a comment about the UK mains plug fuse. It's not there because we have 30A ring circuits - each circuit has a breaker - but to protect the device mains cable in case of a short inside the powered device. Many device cables, including in the EU, will melt and/or catch fire, or at least get very hot at currents allowed by the circuit breaker. The fuse should be rated appropriately for the device in question, regardless of the current rating of the supply circuit to which it is connected.
@ezContents
11 ай бұрын
Thank you for clearing that up.
@RudysRetroIntel
Жыл бұрын
Nicely done. Thanks for sharing
@Xoferif
Жыл бұрын
That was a really good video! I've subscribed. I love the mini CRT TV, by the way. It really looks the part when used with a ZX81. 😄
@JoeldaSilvaVicenteFilho
2 жыл бұрын
9:05 I immediately recognized the clock module hahaha Great video o/
@ezContents
2 жыл бұрын
Thank you! Yes, if you watched Ben Eater's series it is pretty recognizable. 😀
@mslyczba
2 жыл бұрын
Amazing video 👍🏼
@ezContents
2 жыл бұрын
Thank you. 😊
@kevincozens6837
3 ай бұрын
I wouldn't buy a non-working ZX-81 because the most likely source of the problem is the ULA and then good luck getting a replacement.
@ezContents
2 ай бұрын
True. They are hard to find, however I am still thinking of a project where I build an easy to make replacement.
@kevincozens6837
2 ай бұрын
@@ezContents FPGA replacements for the SID chip and the video chip in the C64 have been created. Perhaps someone will create an FPGA based replacement for the ULA.
@tenminutetokyo2643
Жыл бұрын
Jam in new ceramic caps too. 104's
@maximjacquet8434
9 ай бұрын
you can test the sram with your eeprom programmer 😀
@ezContents
9 ай бұрын
Thanks. I was making it too complicated, with the Pico and 3.3V to 5V conversions. Although I think that the problem might have been with the in/out pins, which had 2 functions.
@spacedock873
Жыл бұрын
Pointless doing the composite mod until it is established that a video signal is being generated in the first place! Since you have an oscilloscope (the same one that I and countless hobbyists have!) that should have been tested before getting the soldering iron out. So, basically the first machine has a dead ULA (very common fault) and so is effectively a junk/donor board and the second one worked out of the box. Yes, Arduino is more appropriate tha n a Pi as a test rig for this generation of machines due to its 5V compatibility. On the ROM adapter it is often possible to push out the unwanted pins from the DIP socket which saves fiddly electrical tape insulation. Always Interesting to see a ZX81 since I helped a friend build his kit version back in the day 😀
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