HP427A with an older version of the A2 calibration problem

[TF567577]

Hi

I have an older model of the HP427A that does not have the DC offset adjustment R7. The A2 part number is 00427 66512.

Does anyone have calibration instructions for this version? all of the service manuals I can find have a R7 adjustment.

This meter has transistors that have date codes from 1973.

I would like to keep this to its original build but should I add the R7 circuit?

Hope someone can help

[factory]

According to the 1983 book, 00427 66512 is the third version of A2 and the newest in the book, there is no adjustment that I can see.
The pdf book you have been using is the 1972 version, this is older than your 427A.

David

[TF567577]

Hi David,

Thank you for getting back to me. I will see if I can find a copy.

Cheers