Heathkit T3 Visual Aural Signal Tracer

[Tubejunke]

Originally Posted by jr_tech

Sounds like a ground problem to me .... have you ohmed out the ground connection from the connector to the probe case? How about to where it connects to the 2 resistors inside the probe?

jr

I have gone over the RF probe connections with a fine toothed comb and cant find anything wrong. There is no short in the cable. There is nothing touching inside where the shield goes to 1 Meg resistor and the center conductor goes to a paralleled 47K resistor. The connections are going to the right resistors and they measure reasonably well. I changed the .02 cap. I looked over the connection point at the unit and other than a slop job of soldering on the center conductor point, I see nothing wrong. I got out the Heathkit Cap checker and load tested the .005 (or so) that comes out of the center conductor point at the case.

The only thing left is the diode. I'm not sure how to check that unless it's like checking any other silicon job. So again, the unit is quiet as a church mouse until that center conductor comes into play when I hook it up. Then it works but I have to keep the gain almost all the way off. Grabbing the ground side of the RF cable makes it quiet.