Plus 4 power switch
Posted: Fri Jan 25, 2019 1:43 pm
Got a Plus 4 that wouldn't power up. Power supply was good, fuse was good. Seller assured me it worked before it was put in storage.
Probing the power connector revealed no difference in resistance between 5V and ground with the switch either on or off.
Measuring the resistance at the switch itself revealed that there was no contact made in the ON position.
Wiggling the switch's rocker would occasionally cause contact.
So I took the switch apart, indeed the contacts were oxidized or something like that.
Attached is a picture of the two contacts in there, one is cleaned with a pencil eraser, the other isn't.
See the difference?
Putting the switch back together is another story....
Probing the power connector revealed no difference in resistance between 5V and ground with the switch either on or off.
Measuring the resistance at the switch itself revealed that there was no contact made in the ON position.
Wiggling the switch's rocker would occasionally cause contact.
So I took the switch apart, indeed the contacts were oxidized or something like that.
Attached is a picture of the two contacts in there, one is cleaned with a pencil eraser, the other isn't.
See the difference?
Putting the switch back together is another story....