There's a new youtube video of a guy showing the insides of a ZX81..
https://www.youtube.com/watch?v=Vv715KETc0w
It looks to be heavily modified, I was wondering what this mod might be.
Any guesses, looks like it has a substantial heat sink attached.
Regards;
Greg
ZX81 Mod
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Re: ZX81 Mod
Not seen the video yet. But just going on the photo, the 74LS32 chip is four two input OR gates. It is mounted on what looks like some prototyping matrix board that either has a tinned ground plane on top or it is painted silver. It’s not a metal heatsink.
I would speculate that the OR gates in the 74LS32 may be being used for additional address decoding for either RAM, ROM or I/O.
Mark
I would speculate that the OR gates in the 74LS32 may be being used for additional address decoding for either RAM, ROM or I/O.
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.