Moggy wrote: ↑Fri Mar 01, 2024 11:17 pm
A cell from a de-capped 2c184 ULA, the second picture is a cell with the overlay from Sinclair.
I've had one or two that partially failed, membrane keyboard presses causing a crash but with a Memotech plugged in all ok.
Replacement of the ULA cured it so not a board fault.
Great photos!
I have ‘The Spectrum ULA - How to Design a Microcomputer’ book - a really good read! If a little hard going in places if you don’t have an electronics background.
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