Protek 506/608 how to calibrate ?

[AlexResch]

I have Protek 506 and 608 both bought 2nd hand. They're working but need calibrating. Anybody can describe how that is done ? I have access to voltage standards.

[retiredcaps]

You might be able to deduce the trimmers from

https://www.eevblog.com/forum/suggestions/protek-506-review/

by reading the MAX134 IC datasheet?

[thm_w]

On the 608 there is a "CAL" switch in the top right, you switch that and then use the buttons on the keypad to go through the range and apply appropriate voltage/current. You can only apply cal or skip to the next range, there is no back button. I probably documented it here already.
Don't touch the pots for now.

[BradC]

I have Protek 506 and 608 both bought 2nd hand. They're working but need calibrating. Anybody can describe how that is done ? I have access to voltage standards.

The 506 has the cal procedure in the back of the manual. Oddly enough my 20mumble year old 506 was still spot on everywhere bar temperature, and that only required a tiny tweak.

The 506 manual is available on line as a pdf (as is the schematic) although I don't recall where I found them as it has been a few years.

[AlexResch]

Brad, would it be possible to upload the manual somewhere ? I found the schematics but I could not find the manual.

[BradC]

This is probably as good a place as any.

[AlexResch]

Thank you !!!! I found the manual for the 608 and it also has the calibration procedure.

[IanB]

Just a nudge, in case anyone knows the answer:

I am very interested in the calibration/adjustment procedure for the Protek 6500 DMM. I cannot find information about it anywhere.