29-10-2017, 09:05 AM
(23-10-2017, 10:24 AM)Terry Wrote: Presumably the moving contact moves away from the fixed contact at some point. Assuming that it is contact pressure, rather than oxidation, that is causing the fault, can you push the offending contact beyond its normal limit when the moving contact is out of the way? This might help increase the contact pressure sufficiently.
On the other hand, might the answer be to fix an arm on the switch shaft so that it presses on a small switch to by-pass the contact? Can you identify exactly which contact is the cause of the problem? Obviously stray capacity could make this option a no-no but it might be worth a try.
Hi Terry, I finally tracked it down to switch S28 in the centre of the three wafer assemblies. I unsoldered various wires and components so I could access the contact and I lifted the contact up close to where it is riveted and then pressed down on the other end of it. When I released the 'rivet' end it then had more downforce and so far it seems to be holding up. Time will tell if the contract metal is fatigued or if it will retain the increased pressure. I'll confess it felt like I was repairing a watch, not a radio!
Cheers, John
Time flies like an arrow, fruitflies like a banana!
