Im new here, and have taken posession of a poorely zx81 issue one.
Mine is ULA 2C158e date code 8106, Zilog z80cpu date code 8147, Mostek 1kx8 sram date code 8038. Modulator date code is 8107. Rom is missing. The sram and ula are quiet early, but the modulator and cpu are later. This seems odd to me.
I tried a search, but is there a list somewhere of buggy rom date codes/versions, ULA versus pcb issue, and versions which had 1kx8 vs two 2114s during the great sram shortage of the early 1980s? I.e.
- Issue 1: ULA 2C158e up to date code XXYY, mostek 1k by 8 to date code, buggy rom always fitted to 1kx8 sram boards and issue 1 pcbs?
- Issue 2: ULA 2c184 up to date code AABB, 2c210e afterwards, always mostek 1kx8 sram?
- Issue 3: ULA 2c184e to date code EEFF, ULA 2C210E date code onwards
Cheers, Vincent