Tandy TRS-80 Model 4

-----Original Message----- From: cctalk-bounces at classiccmp.org [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Michael B. Brutman Sent: Friday, December 26, 2008 3:33 PM To: General Discussion: On-Topic and Off-Topic Posts Subject: Re: Tandy TRS-80 Model 4 -snip- The question now is about the conductive pad. Cleaning with rubbing alcohol has not helped anything. Is there anything besides pencil graphite that will work to lower the resistance? I'm looking for something that will last a while, and your concerns about the pencil graphite have me concerned too. I'm not going to desolder and repair every keyswitch so I won't be able to move dodgy ones to the keypad to avoid using them. I'd rather take a little more time and find a better solution .. If I press hard enough on the bad switch eventually the resistance will come down from infinity to around 6000 Ohms. A good keyswitch shows under 100 Ohms of resistance. A picture of the insides of the keyswitch (including the rubber dome contact I'm trying to rejuvenate) can be found here: http://www.brutman.com/TRS80_Model_4_Keyswitch.jpg Thanks, Mike - - - - - There are companies that sell kits to repair those sort of keys, usually to repair remote controls.