Discussion in 'Radio Circuits, Repair & Performance' started by WA4MNT, Apr 28, 2019.
Yes, it is a switch. I could only guess on a replacement. Give me a minute to see what 2N3904 is.
It looks like it should be OK to try it.
My inexpensive says the 2sc4213 is bad
Also remember, the left side of R154 voltage controls Q25. The Q13 side of R153 voltage checks the status of the Q13 emitter (on/off state). It takes at least two conditions to turn on the relay. Maybe more because there are multiple connections to the emitter of Q13.
Does the radio operate normally with Q25 removed?
Oops receive normally with Q25 removed
Well it doesn't go to mute when Q12 heats up. But the voltages are quite different. Q25-B .01V, Q25-C is 3.5V.
I guess I better order the right transistor. The squelch control squelches at either end of the control, but good for the center third of it's range.
I didn't try it without Q25
Different voltage are to be expected. This shows that the control signal shutting down the receiver, via Q13, is coming from Q25 not the control signal for Q25 or other signals at the emitter of Q13.
Did you remove Q25 to test it?