I fished an Agilent E3634A out of the trash bin at my place of work. Lucky for me, the unit was never tagged, so it went into regular trash rather than the magic trash from which items cannot be pulled.
Anyway, it doesn't work. Sometimes when I power it up, everything seems to work OK for a few seconds, then I get an Overcurrent Protection message. However, most of the time I turn it on I get two beeps, all the VFD lit, and then it goes out and nothing. There are a few other strange modes where it worked for a minute and locked up, etc.
I downloaded the service manual and measured all the voltages I could. Everything seems to be in order: 5V on the main board, -5V, -15V, 15V, plus the -17 and +17 that go to the front panel. There might be intermittent problems on one or more of these, but at least when I measure, everything seems solid. Service manual really doesn't have that much in the way of debugging -- though it does have the schematics.
Any ideas where to go next? I am suspecting the display board because of the two beeps at startup, which the manual says means that the processor failed to get a response. I tried reseating the connector on both ends. to no avail. But maybe that is just a downstream symptom of a worse sickness?
Anybody familiar with these units? I can't do all that much testing on the display board because most of the components are mounted under the VFD (why?
).