Today's Mystery Guest (RCA CTC-4)

[Phil Nelson]

Is this what you're talking about -- 270pf cap in parallel with the inductor, and 10pf on the end?



Seems to do nothing around 3.58 mc, but when I went lower, I could get a waveform showing up between about 2.3 to 2.7 mc, peaking in amplitude around 2.55 mc.



Out of curiosity, I made another little circuit using the old L42 and two more caps (10 and 270 pf). The response was basically the same.



So, either the original L42 was good after all, or I still don't have things set up correctly. (Or it could be some evil combination of antique signal generator, middle-aged scope, and antique brain )

Meanwhile, I installed a new inductor in place of the old L42 in the TV and reconnected things to the oscillator tube. No change or improvement. Still seeing 0 volts at pin 6 of the oscillator.

Phil Nelson

[DaveWM]

some obvious stuff here, is the tube socket good (use a test socket to make sure the tube pins are connected to the circuit. Different tube used? correct tube used? just trying to cover the bases.