[AMRadio] Johnson Valiant output capacitors

[Lawrence Steeno]

A while back I posted about where I could find output caps for several Valiant transmitters I have here. One said I should get "snubber" caps from Mouser. Well I did that and they worked. I had several problems with this unit. First, the 300mmf -big square brown one--showed very leaky on my Heathkit capacitor checker starting at only 25 volts! After changing the caps all seemed well for a few minutes--then at times when going to transmit the plate current was pinning the meter and output fell way off. I rechecked the 6146's on my Hickok 800 tube checker, they check great. Back to transmitter, I made a loop of copper wire thru the cathode pins and put a fresh lug to the chassis. No change, check voltages and resistances-no change,loosen and tighten all screws. Then I pulled out my Hickok 539B and checked the 6146's still show good, Looked and scratched my head, rechecked everything--no change, still at times the plate current was pegging the meter. Then I
 pulled out from under the bench the TV2C/U (too much setup to use most times) checker and the tubes still check great. Damn, I pulled out from case the chassis of another Valiant and swapped the 6146's. All is now good!!!!! This goes to show me that one cannot always trust a tube checker no matter how good it is. They check tubes at DC and 60 cycles, not at RF frequencies. Now all seems good. Should get it on 40 this weekend I hope, maybe even of 15 or 10 if open.
Thanks for the responses and NEVER fully trust any tube checker as the final check. Substitution is the final check.
Hard lesson learned but all in all great brain work.
Larry K9LWI