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Replacement 48K Membranes

Ian HamiltonIan Hamilton
edited February 2013 in Hardware
Can anyone recommend a website where I can buy a replacement membrane for my 48K? The only one I know of is Sintech but they charge extortionate amounts for postage. One that takes Maestro debit cards would be ideal too.

Thanks. :)
Post edited by Ian Hamilton on

Comments

  • djgarfdjgarf
    edited May 2012
    try http://www.sellmyretro.com/
  • BloodBazBloodBaz
    edited February 2013
    Hi Guys,
    About 4-5 years ago I bought some replacement Rubber Spectrum keyboard membranes from RWAP and installed them. In the last two months, two of them have failed. In both cases a horizontal slice has cut through the end of the 5-line connector, about 1cm from the end, thus causing the edge keys to stop working.

    The first time this occurred (2-3 months ago) I put it down to bad luck and replaced it with another spare I had from the same original stock I got, but I've just found that another spectrum membrane has come to the same demise.

    I suspect the connector may have dried and become brittle. I've had to scissor the 5-line connector just above the tear but now need to expose the lines again.

    Can anyone suggest a way to expose the conductors? I've just tried scraping at them with a scalpel blade but one 1 of the 5 lines worked.
  • MaccMacc
    edited February 2013
    I blame those voltage regs and the heat they dish out, in an ideal world we would all have nice cool RECOM's fitted and be done with the heatsinks. Not that im saying this has happened in your case (none of mine have failed over a 2 year period except one, but that was down to me using it as a test membrane for every broken Spectrum that came in, which was a lot!)
  • SpiranthoSpirantho
    edited February 2013
    I've not had a problem with Rwap ones myself, but personally I use a Samsung Spectrum.
    I have yet to see one of those membranes fail in any way and they're all 30 years old now!
  • BloodBazBloodBaz
    edited February 2013
    Macc wrote: »
    I blame those voltage regs and the heat they dish out, in an ideal world we would all have nice cool RECOM's fitted and be done with the heatsinks. Not that im saying this has happened in your case (none of mine have failed over a 2 year period except one, but that was down to me using it as a test membrane for every broken Spectrum that came in, which was a lot!)

    Yes, I am seriously considering replacing the 7805 regulators and associated heatsinks in my spectrums with modern switched alternatives. I know that at least one spectrum's keyboard stops working when it gets hot. I think I bought some a couple of years ago. I assume it is just a case of unsolder 3 wires and solder in the new ones in place.

    EDIT: Brill! Just found three RECOMs in my little ZX Spectrum "chips and bits" box.
    Spirantho wrote: »
    I've not had a problem with Rwap ones myself, but personally I use a Samsung Spectrum.
    I have yet to see one of those membranes fail in any way and they're all 30 years old now!

    Are they compatible with Sinclair 48K membranes?
  • SpiranthoSpirantho
    edited February 2013
    BloodBaz wrote: »
    Are they compatible with Sinclair 48K membranes?

    Completely. Samsung Spectrums exist in both "rubber-key" and "plus" form. They're identical to the Sinclair made Spectrums except they're usually Issue 4S and they use different transistors - and, of course, much better membranes.

    If you ever do a composite mod on a Samsung Spectrum, though, make sure you replace TR2 with a ZTX313 as the ones Samsung used aren't very good and make the display blurred when you mod it.
  • BloodBazBloodBaz
    edited February 2013
    Spirantho wrote: »
    Completely. Samsung Spectrums exist in both "rubber-key" and "plus" form. They're identical to the Sinclair made Spectrums except they're usually Issue 4S and they use different transistors - and, of course, much better membranes.

    If you ever do a composite mod on a Samsung Spectrum, though, make sure you replace TR2 with a ZTX313 as the ones Samsung used aren't very good and make the display blurred when you mod it.

    Thanks. Not done any composite mods - I have a SPECTRA interface now which provides high quality RGB SCART output. Although one of my spectrum's is an Issue 4S.
  • rwaprwap
    edited February 2013
    BloodBaz wrote: »
    Hi Guys,
    About 4-5 years ago I bought some replacement Rubber Spectrum keyboard membranes from RWAP and installed them. In the last two months, two of them have failed. In both cases a horizontal slice has cut through the end of the 5-line connector, about 1cm from the end, thus causing the edge keys to stop working.

    The first time this occurred (2-3 months ago) I put it down to bad luck and replaced it with another spare I had from the same original stock I got, but I've just found that another spectrum membrane has come to the same demise.

    I suspect the connector may have dried and become brittle. I've had to scissor the 5-line connector just above the tear but now need to expose the lines again.

    Can anyone suggest a way to expose the conductors? I've just tried scraping at them with a scalpel blade but one 1 of the 5 lines worked.

    That's interesting - I wouldn't mind seeing some photos of the damage.

    It could be down to the heat (or the fact that those ones would have been made in the Czech Republic compared to the ones made in the UK which we currently supply).

    It could also be an issue with the molex keyboard connectors themselves if the damage is where it pushes into the connector.
    Supporting Sinclairs since 1986 !

    www.rwapsoftware.co.uk
    www.sellmyretro.com
  • BloodBazBloodBaz
    edited February 2013
    rwap wrote: »
    That's interesting - I wouldn't mind seeing some photos of the damage.

    It could be down to the heat (or the fact that those ones would have been made in the Czech Republic compared to the ones made in the UK which we currently supply).

    It could also be an issue with the molex keyboard connectors themselves if the damage is where it pushes into the connector.

    Thanks Rich.

    The damage was actually about 15mm ABOVE the contact point, a cut in from the outside end working in. I think it got brittle.
    Shorting between the two molexes still produces key presses and the keyboard was working earlier in the year.

    Well, I've done a successful 7805 Regulator to switched PSU conversion so in future I'm not going to get any -ve impact from the heat sink.

    I've already cut the '5 line' end off to make a fresh edge so I can't photograph it for you. I do still have the sticker that was originally attached to the membrane. It says:

    "NFi PRINTED SWITCH CIRCUIT INNOVATION 931 6A 115"

    It anyone knows of a way to reliably re-expose the ends of the 5-line then that would be great. But I'll probably order a couple of new membranes and do with it.


    Thanks.
  • rwaprwap
    edited February 2013
    That is indeed an odd place for the membrane to fail and it does go back to potential excess heat in the Spectrum.

    It was indeed one of the ones made in the Czech Republic according to that label
    Supporting Sinclairs since 1986 !

    www.rwapsoftware.co.uk
    www.sellmyretro.com
  • BloodBazBloodBaz
    edited February 2013
    rwap wrote: »
    That is indeed an odd place for the membrane to fail and it does go back to potential excess heat in the Spectrum.

    It was indeed one of the ones made in the Czech Republic according to that label

    Well that's good. I believe you are selling new membranes for ?7.50.
    If its okay with you I'll order two more.
    Thanks.
    PS: I received the Spectranet safe and sound BTW. Thank for the fast postage.
  • bversteebverstee
    edited February 2013
    BloodBaz wrote: »
    Thanks Rich.

    The damage was actually about 15mm ABOVE the contact point, a cut in from the outside end working in. I think it got brittle.
    Shorting between the two molexes still produces key presses and the keyboard was working earlier in the year.

    Well, I've done a successful 7805 Regulator to switched PSU conversion so in future I'm not going to get any -ve impact from the heat sink.

    I've already cut the '5 line' end off to make a fresh edge so I can't photograph it for you. I do still have the sticker that was originally attached to the membrane. It says:

    "NFi PRINTED SWITCH CIRCUIT INNOVATION 931 6A 115"

    It anyone knows of a way to reliably re-expose the ends of the 5-line then that would be great. But I'll probably order a couple of new membranes and do with it.


    Thanks.

    Never noticed such a sticker; are you sure those are from RWAP?
    From RWAP are blue ones with the contacts already exposed.
    I have installed about 15 of those and never had any problems with them, but then again I don't keep them that long (they go on eBay) ;)

    Some from eastern-european sellers aren't blue and you need to cut a piece to install them yourself.
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