Is my power supplies dead?

Jack, its me again. I got a new PS, hooked it up and got nothing. So I’m still troubleshooting, I’ve attached a picture of the wires going to the OE PS, do I test the power at the L/N? I’m going to send this PS back just in case I got a bad one, but I want to know what I need to stick my probes to. Thanks

Measure the voltages …


So I measured the voltage coming from the LSP, the red is + and the light blue is -. I got 118v coming from it, so power is getting there. I’ve got to reinstall the old PS to see if its bad or if it goes further than that.

You should be able to measure the mains and both 5V and 24V.

What do you mean lsp?


I meant LPS, fat fingers got me again. I am going to reinstall the PS and see what I am getting on the terminals of it.

You should have around 120 VAC on those two terminals.

Then switch your meter to DC Voltage and see if you get the 24V and 5V

It was reading roughly 118v, I was just touching the 2 wires, didn’t have any alligator clips to clamp on with. Wasn’t trying to shock my self.

118 is close enough. You only need to touch them to take a reading. Just try to touch the probes to the screws. That’s a good place to check voltages

If you don’t confuse the probes with your fingers, it should be quite safe :face_with_spiral_eyes:


I didn’t have the 24v PS hooked up at the time.

Yea… You clearly don’t me!

Although I know there is no color code for any of the wires inside a laser, it’s worrisome that two black wires connect to the +5V / G2 terminals and two colored wires connect to the +24V / G1 terminals. If I were a betting man, I’d lay money the black wires should be “common” to the G terminals and the colored wires to the “positive” terminals.

Perhaps “got nothing” means the laser’s wiring is not connected correctly to the power supply.

That very well could be true Ed, but it’s worked fine for the last 5 year until last week. I also tracked those 2 black wires to the red dot.

I am back in business, I messed it up on my own last night when I installed it… So I’ve got power and red dot using a converter. Thanks for the help @jkwilborn .

I suppose they have a diode bridge in the red dot pointer so polarity doesn’t matter, but … it still makes my (remaining) hair stand on end when stuff like that comes around.

Glad to hear it’s working!

Thanks, glad it’s up and running as well. Well one is negative and one is positive, I had it hooked up one way and it didnt come on, swapped them and it worked.

Well to drag an old thread back from the dead. Lost power again today in middle of job
New PS on order, ordered 2 so Id have an extra on hand so i dont have any downtime.