Hi All ,
I was wondering if any one has ever calibrated an INSTEK DGM 8246. Dual Display
I have the Full service Manual for the GDM 8245 which is supposed to be the same except for the interface plug.
I had a problem with the 20M range it was out by 3 or more meg .
So I followed all the procedures as per the Manual only to find some were not good for my Model or Version
All was going well I did the CL10 CL20 & CL40 400m
. Short Shunt
Used the heavy short . and all was correct.
Then I only had to Cal the 20M range with a 9.90M
. (CL50)
It Calibrated and then I got distracted and Pushed the Auto/man without the shift to EXIT
It reset the 5M range out . and the 20M is F..K and reads 5meg with a 10Meg test resistor.
The Manual said it requires a 3Meg
for the 5M range .. some how its wrong and now that range is out.
That was correct. is messed up now.
Has any one ever calibrated one of these GDM 8246 need 1 to 4.9999M & 20M Ranges
all the other ranges and voltages are correct its just the Meg Ohms .
UPDATE .. Assuming the Manual is correct and I have a slight different version.
There are a few miner component differences from the schematic . to my board .
All the voltages are spot on . except the 6.2v ref which reads 6.8v
my board has the LM399 Precision Reference rather than the 6.2v zener
The Meg ohm ranges were out of cal. when I got it S/H about 3 yrs back.
only about 3 - 4 meg on the 20m range.
I really like this meter and did not want to spend $400 to get same quality
Any help would be More than welcome . Or suggestions on this problem
Also I do have the Full Service Manual for these GDM 8245 If any one is interested .