I got this Metex M-3610 for free. It looks like it was made in 1987.
Unfortunately, it doesn't zero when I touch the probes together on DC voltage. It reads about 0.250Vs when the probes are not touching. When I measure a 9V battery, it reads 0.63V even though it is a new battery.
On resistance mode, the multimeter correctly shows "1" or out of range when the probes are not touching, but when I touch the probes together, I get 25 ohms.
I have tried known good probes and fresh akaline batteries so I'm sure the problem is with the M-3610 itself.
It uses the IC7106 chip and in the datasheet at
http://pdf1.alldatasheet.com/datasheet-pdf/view/177757/INTERSIL/ICL7106CPLZ.htmlit talks about AN032 "Understanding the Auto-Zero and Common Mode Performance of the ICL7136/7/9 Family", but for the life of me, I cannot find the datasheet/app note anywhere.
I'm assuming my problem is with the auto-zero function, but without the app note, I'm not sure what exactly to test.
Suggestions would be appreciated. I know this multimeter isn't worth much, but I want to learn more about electronics and this is a great opportunity.
PS. Now I know why Dave Jones hates those 9V wires. I managed to damage the red wire when snapping back the case on. I didn't see it trapped between the case and screw hole when I put the front cover back on.