Video can't get through IF on Portacolor

[Electronic M]

Originally Posted by Jon1967us

Thanks Tom.

That's the one pot assembly I haven't cleaned yet. I did find tin whiskers in the other two, but I didn't see anything from the outside on that one, so I let it be.

Edit: I did clean this assembly, but no improvement. I didn't spot any whiskers in it, either...

Did you have the negative voltage readings on the 1st IF input and AGC plate as well?

I recall the 1st IF and AGC voltages were badly negative. I believe the grid voltages on the 2nd and 3rd IF were too negative on mine as well. IIRC I remember looking over the circuit and concluding the the plate current in the 1st IF biased the 2nd stage and cascades the same way to the 3rd.

Granted it has probably been more than 4 years since I dealt with that issue.