Auto helm ST4000 worn out switches

[Tarka1]

Hi, as title suggests my autohelm switches are wearing out. I've taken the unit apart and underneath the rubber switches are smaller switches that appear to be self adhesive and stuck on to the circuit board. It's the switches on the board that no longer work as they don't always pop back out as they should. Does anyone know what these are called and where you can buy them?

 

[Allan]

Although I can't answer your specif questions I may be able to help a little. I used to work in the manufacture of PCBs. If the smaller "switches" you refer to are metal, they probably just push down onto conductive ink pads. These small metal discs are normally held in place by some self adhesive plastic sheet. The adhesive can sometimes migrate under the disc and either insulate it from the ink or cause it stick. I have, in the past, had success by just removing the sheet and cleaning around the pads before putting the sheet back. I hope that helps, if not I could bore you with details of the carbons used in the inks and how the soldermask is processed!
Allan

 

[nigelmercier]

I'm pretty sure they are tactile switches:

http://uk.farnell.com/jsp/search/br...ensearch&Ntt=tactile&Ntx=mode+matchallpartial

Measure the dimensions, and take a couple of photographs.

 

[Tarka1]

Although I can't answer your specif questions I may be able to help a little. I used to work in the manufacture of PCBs. If the smaller "switches" you refer to are metal, they probably just push down onto conductive ink pads. These small metal discs are normally held in place by some self adhesive plastic sheet. The adhesive can sometimes migrate under the disc and either insulate it from the ink or cause it stick. I have, in the past, had success by just removing the sheet and cleaning around the pads before putting the sheet back. I hope that helps, if not I could bore you with details of the carbons used in the inks and how the soldermask is processed!
Allan

Thanks Allan, that's exactly what they are but the metal seems to have lost its spring! The other working buttons will bounce back once pressed. I'll try cleaning them up but new might be better. Any idea what glue I'd need to stick them back down?