Boonton 92C repair question

[WB8PFZ]

I have a module 92 rf microvolt meter that has an issue. Everything appears to work but all the readings are 5.5 db high. I am using a Hp signal generator for my rf source, double checking it with a HP spectrum analyzer. Any thoughts. Thanks Mike

[TimFox]

That’s consistent with a generator calibrated for voltage into a 50 ohm (external) load, but a meter with an input impedance much larger than 50 ohms.
I have two similar Boonton units: one is a power meter, where the probe shows 50 ohms to the source, and the other is a voltmeter with high input impedance, supplied with a removable 50 ohm termination.
Ideally, a very high input impedance results in an indication 6 dB high (x2 voltage).

[WB8PFZ]

 Well putting a 6 db attenuator between the rf out of the generator and the rf probe put all the scales in line with where they should be.

[TimFox]

Try adding a 50 ohm termination between the generator and the Boonton probe input.
Note that your spectrum analyzer has a 50 ohm input impedance, but voltmeters rarely do.

[WB8PFZ]

I used a t connector in between the sig. gen and meter with a 50 ohm load and it now reads correctly. Thanks for your insight. Mike