Haas HL2 Hydraulic Power Failure

Hey guys,

Today my HL2 hydraulic system has stopped functioning. Steps:

1. Turn machine on. Loud buzzing sound from rear/side of machine. Hard to tell if it was pump area or electrical box.
2. Turn machine off.
3. Turn machine on. Loud buzzing sound again.
4. Let computer boot. Buzzing stopped.
5. Pushed reset to engage servos and hydraulic pump. Nothing happens. After about 1.5sec, alarm triggers saying Low Hydraulic Pressure.

Hydraulic pump isn't even trying to come on now. Now when I turn the machine off and then on, there's no buzzing. I left it for 15 minutes to let it cool if needed and turned it back on. Still nothing.

I opened up the back. I see no breakers tripped. No fuses blown. There's a large 10 pin relay that looks like it could be for the pump - it triggers when pushing reset and releases when the alarm hits.

For the past bit, the linkage in the hydraulic pump has been getting stuck - you push reset and hear it get stuck and then kick off. After a couple tries it comes on. I was trying to get a job finished and was scheduled to disassemble it and repair the linkage on Monday. My gut feeling is this has caused an electrical component to fail. But the fact that the loud buzzing occurred when the machine turned on but before I reset to engage the hydraulic pump tells me that's an isolated issue.

If anyone has any ideas about tackling this electrical issue for the hydraulic pump I'd greatly appreciate some input.

In case anyone finds this, I believe we've found that the relay for the pump is bad. The noise we heard was probably the pump single-phasing. We've got it working again, although sometimes still occuring. New relay on the way.