Quote:
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.
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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.