Hi at all,
i find this 48k board.
What ar missing on this board?
The ULA is shorted to ground. Any replacement for this?
Thanks,
Matteo
What are missing on this board? (48k Issue 3)
Re: What are missing on this board? (48k Issue 3)
This is the ULA, upper 32k memory I think (8x TMS4532-20) and a few logic chips.
See the link here for a high resolution graphic:
https://upload.wikimedia.org/wikipedia/ ... rum_mb.jpg
See the link here for a high resolution graphic:
https://upload.wikimedia.org/wikipedia/ ... rum_mb.jpg
Re: What are missing on this board? (48k Issue 3)
Thanks so much pokeMon.
Matt
Matt
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Re: What are missing on this board? (48k Issue 3)
And the aluminium heatsink for the 7805 voltage regulator is also not fitted...
Mark
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.
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.
Re: What are missing on this board? (48k Issue 3)
Mark, i have it
I have removed for the photo.
Thanks,
Matt
I have removed for the photo.
Thanks,
Matt