Instek GDM-8135 Digital Multimeter

[jmoorsie]

The resistive measure is dissfunctional on a Instek GDM-8135 Digital Multimeter. Example: on the 2kΩ setting selected on the meter, the reading with a 1kΩ reads .01kΩ and with a 19kΩ resistance it measures 1.73kΩ with the meter range at the 20kΩ setting. Attempts to calibrate using table 4-3 in the owners manual adjusting pot number 401 as instructed had no response. Then I adjusted the 402 to see what would happen, and nothing. I am looking for the schematic diagram for the unit but of course to no avail for the obvious reason. The manual appearently did not have the schematic included. If anyone can instruct me at resolving this issue or has a way of attaining a schematic, I'll buy you dinner, if you live in Nashvill TN that is. Ha Ha. Thank You !!!!

 

[kking]

We have many of these meters also and I had one that appears to have a problem that appears related to yours. It was brought to me for repair. When measuring VDC I measured a AA cell and found that it measures 1.45 DC on the 2 V range, 14.5 on the 20VDC range, 145V on the 200VDC range and 1450V on the 2000VDC range. I sent a message to Instec and am waiting on a reply from them.

 

[mdanh2002]

I also have an analog multimeter that has a similar problem. The x20k (resistance) doesn't work. When I switch to that scale, the meter show infinite resistance (open circuit) no matter what resistor values I try to measure. Thinking that the dial maybe old and has loose connection, I open up and check but cannot find anything unusual. All other resistance scales shows some reading, except the x10 scale. 1k resistor reads about 500-600 ohms, 2k reads as around 1.3k. The zero-ohm asjustment doesn't help.

Any ideas what the problem is?