Sinclair ZX80 / ZX81 / Z88 Forums

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...

Hi well i went with the fact the long leg on the 22uf cap was positive facing the pluss sign on C3. It is an issue 3 zx81 in red. Yes lifted pad in pic

Greetings all. I bricked my zx81 after successfully doing both a composite mod and transformer mod for cooling and tv output. After de soldering 22uf cap and replacing i got no signal output. Replacing same effect.. then removing that i accidentally damaged a tiny bit of the board. Now i have two pr...

Was just thinking about squeezing a joystick pork inside a zx81. Taping the 5 6 7 8 and 0 keys should be possible with some careful soldering to the keyboard membrane sockets on the board. Tried it yet anyone?
I thing the tophalf of the membrane leads to one socket the bottom half to the other..