Sinclair ZX80 / ZX81 / Z88 Forums

My Zx81 has a death wish.. I attempted to add a LED supporting a resistor tappin the 12v from the boad. From that point i got no signal from Tv composite out. 1. Desolderd power to LED Problem continues 2. Replaced transistor Problem continues 3. Replaced diode Problem continues 4. Replaced 22uf cap...

I have a feeling i might be crushing everything that's sacred but i decided i want to give this old 80s icon a complete face lift.

Here is a sneak preview so far, "forgive me Sir Clive i know not what i've done"

Ok just need a new keyboard membrane for my poor old zx81.. gulp

While risking life and limb i decided to fit a power on led to my zx..

Tapping 12v to a pre made resistor amd LED drilled hole and dab od solder... all good

Holy moses !!!!!

I think i cracked it i tried one of these diodes and a 1W-100R resistor no idea if it means 100oms but bingo

Its nuts thanks everybody !!

See pics

Ok good news folks back in business again... I found i had accidentally shorted a wire inside the metal box housing where the plus 5v wire was snipped. So now the computer powers up So here is something weird. That 22uf i replaced only the minus side actually had a real connection and that was going...

Great tip

Looks nice. Would be interested to see the volume control. Manic Miner wakes the neighbours when it loads! :shock: I am a complete novice but my plan is to snip one of the connectors to the speaker and bridge both ends with a vairable resistor.. This should change the volume leval. I need to find o...

It's always possible that some component was damaged during handling of the board, in-between powerups to test things, ESD damage etc. But for the NMOS IC's in a ZX81: highly unlikely. If not that, following method is practically foolproof: start from last configuration that you KNOW 100% sure to b...

Thanks for feedback appreciated

I took some screen grab pics which give a clue to the morphing of the zx81 into spectrum from humble beginning- the umbilical chord if you like :-) Source Youtube Published on Apr 3, 2019 Wires, chips, hand-written key caps, somehow this early version of the Sinclair ZX Spectrum survived. Jason Fitz...