Sinclair ZX80 / ZX81 Forums

Here you go Lardo.

Just run it and drop an O file onto it then save.

One bug with it though it saves at too high a frequency (44khz) so you have to drop the said wav into something like Audacity or wav editor of choice and save again at 22Khz. A bit of a bind but it produces a nice loud wav file.

Just to be going on with Lardo full fide 1k chess for the ZX80 takes approx 30 secs to load so not having to wait half a day to see if it works and slightly more interesting than yet another mastermind clone. :lol: I have a O file to wav jobby I can dig out and post. Cursor controls are Q-A (up down...

Lardo Boffin wrote: ↑

Sat Sep 14, 2019 6:58 pm

Also


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I too have this book and have found it to quite informative.

Back in the 1980's I was really into Z80 programming on the ZX81. I had a book that was my go to reference for programming but sadly over the years it got lost and I have forgotten the title. At first I thought it may be Toni Baker's Mastering Machine Code on Your ZX81 but after firing up the old b...

Thanks for that information Rich, handy to know.

Well I got up this morning after drowning my sorrows over my busted 80. I went over Marks advice and recommendations again and the bit about loose sockets seemed the only answer even though I was getting continuity from the bottom of the board to the CPU pins. So yesterday I replaced the ROM socket ...

Too much whisky and too tired to go further but if needs be then I will happily solder the chips directly to the board. Many thanks Mark by the way for the time and trouble you are spending on this. I am very very grateful. Just as a side issue of no importance. I have converted a ZX81 back to ZX80 ...

Unfortunately the RAM chips are not socketed but tried with RAM pack and no difference.

Checked for continuity from underside of board to each pin on CPU and ROM and all ok with nil resistance.

Story so far. Tried 4 known good and tested CPU's Replaced ROM with ZX81 ROM as I have a glut of them and can afford to lose probably one or two trying. Replaced the composite video board with original modulator just in case that had blown. No joy just a white screen on power up. I'm now officially ...

Hi Moggy So just to be clear, the only chips you changed were the Z80 and the ROM/EPROM chips, yes? The symptoms are a white screen only (no inverse K) and the +5V supply is present and correct on all chips. So my questions so far are (and forgive me if I start with the obvious things that you may ...