[TenTec] Corsair II problem

[Don Rasmussen]

Thanks Dr. Jerry,

I swapped the 68C05 into another radio and it works fine. There is 5V on the pins where it is required, and I can hear the crystal oscillating using an external receiver. All this, plus the fact that it worked intermittently for a couple cycles before it finally stopped working seems to indicate that the capacitor on the RESET pin may not be allowing the processor to do a reset at power up. I'll try to find something near 2.2 mf to test with and order the proper part if that works. Thanks for the info. Don.

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The counter, display driver, and keyer are all done by a 68C05 on the 
display board. It fails when the electrolytics go bad. It can also fail 
from loosing power from a dirty board connection. It doesn't control any 
of the radio, so everything else will work without the display, just you 
don't know easily here you are tuned. History says replacing the 
electrolytic or two on that board usually fixes it. Order up the lowest 
ESR, highest temperature rated one from Mouser or Digi-Key to get the 
longest life.

73, Jerry, K0CQ