Hi,
I recently scored a HP 34401A Multi-meter off the web with a non-working status.
It Has following Issues
- It's reporting Error 604.
- DC measurement is extremely inaccurate.
- Ohm measurement is non-working, but do reports ~ 0ohm if I short the test leads.
- Conductive Test is Working as excepted.
As I tear it down, measuring the DC supplys, +-18V +- 15V and 5V, are all good
and Voltage refs, 7.5V, 5V, +-10V, are also good.
IC, Numbering U420, U105, U106, U312, U305, and voltage regulator are all hot as about 40~45 degrees Celsius, as other chips are 33~36 only.
Any way to repair this thing or to do more detailed testing?
Any suggestions welcomed.