help with a potentiometer/mv meter

[pdxgearhead]

I have an old 1970s pH/millivolt meter. When used as a millivolt meter, it has a measurement range of +to- 400mV. For an experiment, I'd like to modify the meter to a range of +to- 50mV. Is there a way to do that, for you electronics junkies? I do have a wiring schematic of the meter. Thanks for any help.

 

[ddawg16]

It depends on what the range of the bare meter is.

Can you post the schematic?

Chances are you will need to modify the voltage divider network.

 

[justsam]

Look at the corners of the face of the meter movement itself.
You are looking for something like fs=50mv or similar.
The more sensitive the basic meter movement, the more costly the meter.

 

[pdxgearhead]

I have a pdf of the wiring diagram, but since its a pdf and not a jpeg, I can't get it to upload to Photobucket.

 

[dslabuda]

Dropbox, Google Drive, Skydrive, etc. One of the free cloud services should work. You can upload a file, then post the link.

Sent from my SAMSUNG-SM-N900A using Tapatalk 4

 

[pdxgearhead]

Here you go