Hello everybody. My first time in this forum, I appreciate the level of discussion and the competence of many people.
I recently started to work around tube amplifier and set-up a small laboratory, really as a beginner.
I found a Fluke 8800a in a local website of old stuff and bought it for few euros.
It worked good for AC/DC measurments, but not for Ohms.
I open it, cleaned, substituted batteries on the Ohm PCB (2xAA - the previous ones had a leakage so it was a dirty job).
All the ohm measures are now greater than real. In example a 1.2MOhn resistor is 6MOhm if measured with 20MOhm scale, or 1.6MOhm if measured with the 2000kOhm scale. During time (hours) the measures on the display decrease gradually.
I tested all the power levels indicated in the manual on the main board and they are correct.
I tested the Ohm PCB with 1Ohm resistor, and the voltage drop 1mV as indicated in the manual.
I check the power supply by the batteries all around the Ohm PCB and it's a nice 3.2Vdc.
Any suggestion? Iknow it's an old device, but quite accurate on the VAC/VDC part and an opportunity for me to learn something new.
Thanks in advance for your help.