Chromatography Forum

Agilent 6850 GC, about 15 years old. Powered on the GC after lockdown was lifted, it powered on briefly then went off, cycled the power again and same thing happened then wouldn't power on again.

I tested all four fuses on the AC board and all three fuses on the main board and they were fine. The fan in the back of the GC (connected to the main board) still spins, but the lights on the LAN card aren't lighting up. I don't see any other lights on the boards, but not sure if there should be any. I do have a second GC of the same model so I could switch parts to try and figure out what needs to be replaced, but was looking for any insight as to what I should be looking at first, and whether there was any risk I could damage the second set of parts by doing so...


Thanks!

Sounds like a power supply unit problem .

Just thought I'd follow up with how we ended up fixing the issue; the solution was to change the voltage regulators on the main board - although we think that the -15V was the problematic one, I believe we ended up switching most of them since it was easier at the time. To note that there are test points on the board itself, which should help you diagnose the issue should you ever come across it.

Ultimately, we believe it is the VFD display upfront that short-circuited and may have taken out an aging regulator (once we resetup, it smoked) so we disconnected the VFD from the front since we didn't really need it due to the PC control.