Easiest way to fit 2732 EPROM in ZX80?

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RetroByte
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Joined: Mon Mar 12, 2018 1:33 pm

Easiest way to fit 2732 EPROM in ZX80?

Post by RetroByte »

Hello all again.

Without any extra adaptors, what's the easiest way to fit 2732 EPROM in ZX80?

It looks like pin 18 on the ZX needs connecting to 21 on the Eprom, but what do I need to do with the other two pins 20,21 on the ZX, 18,20 on the EPROM?

Thanks for looking ;)
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1024MAK
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Re: Easiest way to fit 2732 EPROM in ZX80?

Post by 1024MAK »

See this web page or if the link breaks, search for “Grant Searle How to build your own ZX80/ZX81 (verified working) and how it works”.

Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp

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RetroByte
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Joined: Mon Mar 12, 2018 1:33 pm

Re: Easiest way to fit 2732 EPROM in ZX80?

Post by RetroByte »

Thanks Mark for the quick reply, I will try the same mod tomorrow :)
Moggy
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Joined: Wed Jun 18, 2008 2:00 pm

Re: Easiest way to fit 2732 EPROM in ZX80?

Post by Moggy »

I've done this mod with a 2732 and whilst it worked the bottom pixels of the cursor were shifted one pixel to the right, but that could have been a timing issue with the EPROM I used.
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eprom2732.jpg
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RetroByte
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Re: Easiest way to fit 2732 EPROM in ZX80?

Post by RetroByte »

So far so good! :)

Don't worry, I'm going to cover the UV window :)

You can see from the photo I used a ST M2732A-3FI, that I bought from eBay. I flashed it with the cheap TL866CS that I've moded for an extra 5v input ,I'm not sure if it needed the extra power or not, I think the TL866CS can only manage 18v with USB power only. It took a couple of flashes to get it to program.

I will test with some games now, just to make sure :)

Thanks.
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1024MAK
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Location: Looking forward to summer in Somerset, UK...

Re: Easiest way to fit 2732 EPROM in ZX80?

Post by 1024MAK »

Well done :D

Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp

:!: Standby alert :!:
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb :!:
Looking forward to summer later in the year.
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