Moggy wrote: ↑Wed Oct 09, 2019 4:30 pm
Looks very nice.
I'm guessing issue three, NEC ROM and CPU and back porch ULA. (That's if you open it up )
I think I may just sell this one on untouched. Far too nice!
Looking inside via the edge connector it is an issue one with the cream PCB on top, green below and everything is socketed. It doesn’t have a bugged ROM. For a change!
The output is dark but not ridiculously so.
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
The empty sockets are too small for most EPROM/ROM chips. It could however be some kind of RAM card, but using small SRAMs. I base this on them all being connected to the data bus.
The 74177 chips are counters, but may be being used as latches.
In any event, this looks like it was hand soldered and could be a home made / DIY or a magazine project.