[daveone23]

Any of you guys have one of these signal generators. The manual says it has a built in vtvm, I assume for testing db, but it doesnt say how
to use it. There is only one probe input on the front of the machine.

[Chas]

Here is the manual, seems you have snipped a schematic page already:

https://elektrotanya.com/hickok_19xd_mic...ad.html#dl

Page one states the VTVM is only 1 uv and one scale only. Seems like a special purpose device...