Petri Color 35 Light Meter Problems

[caspert79]

I just tested the light meter of my Petri Color 35 with a 1.5v button cell. The original battery however is a 1.35v mercury cell button. Unfortunately, the light meter shows overexposure in every setting (even with f/22, 1/250, ASA 25). What is the most plausible cause for this problem? Is it the battery, is it the calibration or perhaps something else.

 

[mongo141]

I just tested the light meter of my Petri Color 35 with a 1.5v button cell. The original battery however is a 1.35v mercury cell button. Unfortunately, the light meter shows overexposure in every setting (even with f/22, 1/250, ASA 25). What is the most plausible cause for this problem? Is it the battery, is it the calibration or perhaps something else.

I have one of those and yes it is out of calibration because of the voltage differance. It can be calibrated for the newer batterys but it is a time consuming process and the top has to come off. There is a couple of very tiny variable resistors set up as a voltage divider network and both require adjustment. I did mine just to see if it could be done and it worked very well but it was a pain in the rear end to do.. Dave

 

[caspert79]

It's allready working right now! Don't ask me why, I just took the battery out and put it back again. But I will get a 1.35v anyway.