[volt-nuts] Problems with 720A

[David C. Partridge]

You knew this was coming I'm sure:  It was almost inevitable that there
would be problems with the 720A!

While trying to self-calibrate the 720A, (CAL A) the at the 0.1 and 0.10
settings the null meter was way out with around 100mV out of balance, and
the A.1 and A.10 pots seemed not to do anything.

I'm trying to work out from the schematic what's likely to be wrong, but so
far am not clear where the fault lies.

I *think* that when I have the main switch set to CAL A and the A decade set
to 0.1 that I'm balancing R311, R1044, R1042 and R1041  against the leg of
the bridge comprising R1, R206, R207, R208 and R209

Similarly for the 1.0 setting of the A decade, I think the resistors are
R302, R1008, R1006, and R1005.

Have I read this correctly?

Thanks
Dave