Quote:
Originally Posted by Jon1967us
Well, it seems that the detector diode is hidden in the metal can as indicated by the left most arrow. I have no way of getting to it other than spending 4 hours disconnecting and desoldering everything to remove the board. This board is totally unserviceable.
Also, the Vid output tube has the test pins INSIDE the tube cover. No way to get to them with the tube in. The Mercury tube checker says the tube is fine by the way. Could I check the bias voltages with the tube out? Otherwise, there are barely visible traces by the socket. I may be able to check the voltages there.
Back to the detector diode, what are the chances it has failed? Do these old Ge Shottkeys have a reputation for failure?
Note, I am feeding a video signal in with a D>A converter box, connected to the antenna lugs. |
They make a tool for getting those voltages with the tube installed... called a socket extender or socket saver....they go between the scoket and tube, lift the tube an inch or two and have test points on top.
I'd reckon video detectors prior to the late 60s had a 30% failure rate... the older the worse.
Most weren't shottkeys but Crystal diodes....they predated the transistor in consumer electronics.