Somebody give me a little nudge? Philco with no video

[Notimetolooz]

Originally Posted by AlanInSitges

I have verified that the video detector is OK, or, at least checking like a germanium diode with a 2.65v drop one way and open the other.

I don't know enough about IF and RF to understand how my probe may be affecting the behavior of the circuit, especially on the plate of V2.

Results when testing that diode with a meter depend somewhat on the type of meter, but this probably is a germanium diode and so the voltage in the forward direction should be more like 0.25 to 0.5 V.

Is your meter a VTVM or a DVM? A typical DVM or VOM meter will add capacitance to the point the probe touches. This effects the IF/RF level. The usual VTVM has a 1M ohm resistor in the DC probe. This resistor isolates the probe tip from the capacitance of the meter and the leads, making the capacitance loading much less.