So this machine was my second computer and this here is my personal one from 1986 so yup this Christmas it will be 40 years old.
I was surprised to find it had RGB output already so straight on the Internet I bought the correct cable from Retro Computer Shack and first test along with the OG power supply from the Megadrive it worked first time.
So I noticed there was 2 service stickers below from G.C Electronics Consett. I spoke with my dad who couldn’t remeber what was wrong so I popped it open to investigate more.
So what I noticed was a ceramic disc capacitor below D35.
Which Google search came back with.
For the grey ZX Spectrum +2, placing a 82pF or 100pF ceramic capacitor over diode D35 (and sometimes D33) is a common, well-documented modification used to fix issues with keys not working when the computer is cold. This mod solves problems with overloaded address lines, often referred to as “ULA snow effect”.
And
SS+A, and some other keys not working when computer is cold
This is caused by overloaded addres lines. Put 82pF or 100pF ceramic capacitor over diode D35 (on some machines also over D33) and problem will disappear.
More investigation, this was a factory mod. So not work done from repair shop.
Next on the Datacoder, there was a disc and radial capacitor.
Could these be the work from the repair shop.
Well ……. nope another factory mod found on spectrumforeveryone site
So still couldn’t find the repair still stairing at pcb for hours and something jumped at me.
IC32 was different from the rest. That’s the repair.
The TMS4164-15NL is a vintage 64K x 1-bit Dynamic RAM (DRAM) chip from Texas Instruments. So it seems like we had a memory issue.
Only work dine so far is cleaning the springs, keys, and membrane.
So that’s enough so far. Few mods and fixes to do. Along with building tzxduino as well. But now, image dump.
