Keyboard not working on 3 speccys

I have 3 zx spectrums 48k (One was the original one I had as a kid with rubber keys) and I just purchased 2 more.. one original spectrum 48k with rubber and the second one is the 48k + (plus) with the hard plastic keys.

so here are the problems I have:

1) My original 48k with rubber keys turns on but only some keys work
2) the 48k with rubber keys turns on but no keys work
3) the 48k plus turns on but only some keys work.

So here are my questions:
I saw on youtube where they were repairing the membanes by opening the speccys up and trimming the ribbons. I tried that on the one that speccy with the rubber keys that the keys dont work at all because it seems that the ribbon was only broken at one spot.
But that didnt fix the issue. Still no keys work
Could it be something else other than the membrane? In other words could something else be causing the keys to not work.

And for the other ones that they keys partially work do you think that if I buy a membrane for those will it fix the issue?

Last question.. is it hard to detach the faceplate from the original 48k zx spectrums? I have a heatgun that might help.
I dont want to ruin them! I saw that they have replacements but I want to try to avoid that to keep the cost of the repairs at a minimum.

THANK YOU!!!!!!

Comments

  • kuser wrote: »
    Last question.. is it hard to detach the faceplate from the original 48k zx spectrums? I have a heatgun that might help. I dont want to ruin them! I saw that they have replacements but I want to try to avoid that to keep the cost of the repairs at a minimum.

    The safest way to remove the faceplate is with a normal hairdryer, but wear gloves because they get hot! If you use a heatgun it will be far too hot and you will melt things, also the glue melts really well with just a normal hairdryer. :)

    I think trimming ribbons is a losing battle, if they are cracking already (and they will all be cracking by now at some point) then they'll just crack further up the membrane. :/
  • The vast majority of keyboard faults on 16K/48K/plus/128K (toastrack) machines are due to a failure (partial or total) of the membrane.

    Get new membranes ;)

    Rubber key

    Plus / 128K

    If you want to prove that your machines are working (other than membrane problems), use a thin piece of solid core wire (e.g. fixed wiring telephone cable or network cable), strip some insulation off the ends, then briefly touch each end on contacts in each of the two keyboard ribbon cable connectors. That is, one end of the wire in one connector and the other end in the other connector. There are eight contacts in one connector and five contacts in the other. If you go through all 40 combinations, you can simulate every keyword ‘key’...

    No, please don’t ask how the plus has mote than 40 keys...

    Otherwise I will have to tell you that
    Spoiler:

    Mark
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