(some) keys stopped working after bolt-mod

[hanshan]

Any idea welcome - I had an old mainframe model M that I successfully reconstructed with a [used] pc membrane & controller - everything worked find for several weeks - now the "8 - 9, I - O, K -L, > - ?" bank doesn't register, as well as "+/=, }/]" keys.   I have tried adjusting the pressure by tightening and loosening the bolts - no success so far.  I can't determine if it's the membrane, controller, or build. Would appreciate guidance - thanks.

[Snowdog993]

Any idea welcome - I had an old mainframe model M that I successfully reconstructed with a [used] pc membrane & controller - everything worked find for several weeks - now the "8 - 9, I - O, K -L, > - ?" bank doesn't register, as well as "+/=, }/]" keys.   I have tried adjusting the pressure by tightening and loosening the bolts - no success so far.  I can't determine if it's the membrane, controller, or build. Would appreciate guidance - thanks.

Do the keys buckle properly?  If they do, half the battle is won!  The primary suspect is the ribbon cable that connects to your controller.  Carefully remove the ribbon from the controller and clean all the contacts.  Believe it or not, I usually use a pencil eraser to remove residue from the ribbon.
Be sure your contacts are clean also.  Once done, reconnect the ribbon cable and check it again.  If everything is seated properly, you should be fine.
Hopefully this will help you out.

[hanshan]

Thanks, I appreciate the suggestion but have tried that - the keys all buckle correctly, I have cleaned the ribbon cable contacts thoroughly - Unless there is something I am missing, my only alternative now is to tear it down, examine the membrane for defects and if I find none, rebuild it.  I have another Model M (betcha can't have just one) and will swap controllers - Once that is done, if it still doesn't work, I guess I will have to try a new membrane - I do like this board - its heavier than the later model M - has the square silver logo, and I drilled out holes for the indicator lights (the mainframe board were blank) and added the correct applique that I purchased from Omni - clearly not ready to give up on this one.

[False_Dmitry_II]

You should be able to buy a new membrane from Unicomp if it comes to that.

[hanshan]

yup - thanks - will try to get to it this weekend & see where I end up -