Hey everyone.
I'm very new to electronics as a hobby - I do a lot of reading and light tinkering, but this is my first foray into trying to do anything for real. Unfortunately, it's not how I planned to start, but here we are.
I just got a Lecroy 9324 that was was for sale as parts only, but was shown working at the time of shipping - no errors, waveform looked good. Just got it in, and it does not appear to turn on. There are no lights or indicators on the front panel to check, but the fans on the case aren't spinning - so I'm hoping it's just the power supply.
I can't find the service manual to start probing around - anyone have any hints? Tried searching and google, no avail.
Things I've checked so far:
On power, no display and no fans spin. A high pitched whine comes out of the power supply. Took the power supply out of the scope and have it powered on my bench. On investigation, the sound is one of two inductors bunched very close together. I can't figure out which one is making the noise. Putting metal in/around the inductor does not change the pitch of the whine, but light pressure on any of the capacitors nearby changes the pitch drastically.
The voltages do not appear okay. The PSU has +/- 5 and 15 volts listed as output (not on any particular pin mind you, just printed on the case) and I'm getting 2.5 and 12 volts with major variance between the pins.
On the AC side, there's even stranger nonsense. I've got three pins: Pin 1, a brown wire and assumed hot; pin 2, blue wire and assumed neutral; pin 3, yellow with green stripe, ground.
I have 124 volts between hot and neutral, but I also have 51 volts between neutral and ground, and 72 volts between ground and hot. Very interesting, after doing the addition of those numbers. Ground is not actually connected at the moment, because the ground jumps directly to the chassis before connecting to the power supply. I could hack together a bridge and connect it, but I feel it's better to leave it the hell alone until someone else chimes in who understands more than I do.
Any suggestions or comments are welcome, this is not really how I was imagining starting out.
Edit:
Just found the correct pin-voltage chart for this power supply, it turns out all the DC voltages are correct (at least while not under power). Not sure where to go from here.