Hi folks,
I've been given a 128k spectrum by a friend for my son who collects retro consoles and computers but it seems to have an issue and i was wondering if you lovely folks could give me any advice before i got at it with my screwdriver and soldering iron .
So the issue is the computer boots to the selection screen but there is a constant repeating click ,and the keyboard doesnt seem to inputing anything, ie i cant make any selection. The sound stops if you if you push a key and resumes as soon as you lift off a key , this happens on all keys except the z key !! does this sound like a dodgy/dirty keyboard membrane issue ie the z key is stuck on ? or has anyone had an issue like this on a speccy before? thanks in advance for any help you could give me .
128k issue
-
KeplerOfMars
- Drutt
- Posts: 45
- Joined: Mon Jun 26, 2023 6:23 pm
Re: 128k issue
The first thing I would do is open the machine and very carefully disconnect the keyboard membrane. Power the machine back on and you will know if the keyboard was causing the problem.
Keyboard membranes are notorious for corroding over time so you will probably need to replace it. But a quick visual inspection of the two points where it connects to the motherboard will clarify that for you.
Keyboard membranes are notorious for corroding over time so you will probably need to replace it. But a quick visual inspection of the two points where it connects to the motherboard will clarify that for you.
-
Ast A. Moore
- Rick Dangerous
- Posts: 2643
- Joined: Mon Nov 13, 2017 3:16 pm
Re: 128k issue
It is indeed a stuck key. If it’s mechanical (i.e. the membrane or the key caps themselves), you could try gently pushing on each key and wiggling it around a bit.
Every man should plant a tree, build a house, and write a ZX Spectrum game.
Author of A Yankee in Iraq, a 50 fps shoot-’em-up—the first game to utilize the floating bus on the +2A/+3,
and zasm Z80 Assembler syntax highlighter.
Author of A Yankee in Iraq, a 50 fps shoot-’em-up—the first game to utilize the floating bus on the +2A/+3,
and zasm Z80 Assembler syntax highlighter.
Re: 128k issue
Is it a (i) black 128k Spectrum (red 128k logo bottom right, large metal heatsink on the right hand side)? Or is it a (ii) grey or black +2, 3 with a built-in tape deck / disk drive on the right hand side?
I ask because the keyboard mechanisms are different. I've had a mildly mechanically stuck key on (i) that just needed freeing from the adjacent keys and the membrane was fine. With (ii) I had a stuck key because the keyboard as a whole was bent into a concave shape - caused by something forcing the keyboard down into the casing and breaking two attachment posts and then bending the backplate. Also with (ii) the keys press springs into the membrane beneath and I've seen a spring embedded in the membrane. (i) has a rubber mat between the keys and the membrane.
I ask because the keyboard mechanisms are different. I've had a mildly mechanically stuck key on (i) that just needed freeing from the adjacent keys and the membrane was fine. With (ii) I had a stuck key because the keyboard as a whole was bent into a concave shape - caused by something forcing the keyboard down into the casing and breaking two attachment posts and then bending the backplate. Also with (ii) the keys press springs into the membrane beneath and I've seen a spring embedded in the membrane. (i) has a rubber mat between the keys and the membrane.