While Lardo continues to trade over on Lardo buys another zeddy, I continue to rediscover (from storage) machines that I have previously obtained.
Although, I can’t always remember the history of them…
Like this one:
I obtained this one in November 2017. For some reason, the heatsink is no longer attached, and it looks like I renewed both electrolytic capacitors. The keyboard membrane is broken (as expected).
I will have to investigate further when I have time…
But meanwhile, it’s interesting because all chips are directly soldered.
Model: ZX81, U.K. version.
Serial number: none
PCB: Issue one, green solder resist on bottom only.
Modulator type: UM1233 (UHF channel 36), date code: 8226
IC1 - ULA - 2C184E, date code 8233
IC2 - ROM - Motorola ZCM3881C, date code 8237, ceramic case,
IC3 - MPU - SGS Z8400AB1, date code 8208
IC4 - RAM - MOSTEK MKX4118P-4, date code 8040, with gold top ceramic case!
Notes: apart from the two electrolytic capacitors having been renewed, no sign of any other rework on the board.
Mark
My Zeddies…
- 1024MAK
- Posts: 5118
- Joined: Mon Sep 26, 2011 10:56 am
- Location: Looking forward to summer in Somerset, UK...
My Zeddies…
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.
-
- Posts: 2169
- Joined: Sat Nov 26, 2016 2:42 am
Re: My Zeddies…
I have a vague memory of selling you a zeddy with a goldy-looking RAM chip a while back as I didn’t want to refurbish it as it was so cool looking but my ‘buys another zeddy’ only goes back to 2019.
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
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