(Edit: Fair warning, this is a long story with many twists and turns. With a bit of a cautionary tale, or two, thrown in if you will.)
Ok need some help. Just went to turn my laser on and nothing happened. Checked the fuse at the plug it was good. Checked the AC power at the LPS and it’s getting 125V AC. So something is wrong with the LPS.
Worst possible timing for me right now. Ordered a new one from Amazon just in case for delivery Monday.
Any ideas on what to check? @donkjr
Is there continuity between G and P?
Do you get anything on the 5 V and 24 V rails?
Showing 20M ohm between L&P. Nothing on on the 5V or 24 rails.
Opps getting myself mixed up. 0 ohms between G&P. So continuity.
The internal fuse is good.
Did you check the fuse that is IN the power supply?
Ha! You answered while I was asking!
That’s why I keep a spare around. You never know when they will crap out.
Yeah, I should have had a spare on hand. 
Is the green and red led on the pcb illuminated?
Does it fire with the test button on the supply?
Nothing lights up and no response on the on board test fire button.
So going by your blog, it’s possibly the DC power supply PWM controller?
Usually the Big fat Schottky diode that delivers the 24V DC blows out. Changed mine about 10 times 
The schottky diode has just a rating of 1A so maybe use a faster recovery spec Schottky with higher current?
Yah but it did not blow a fuse.
And no green led means LV side is dead…
I know, I have the same issue. Never blows a fuse, just the schottky diode. I don’t even bother to desolder the diode from the PCB. Just cut off the leads and solder the new one directly onto the old leads.
@NedMan you can snip one side of the diode and then measure it… for open/short.
No burn marks anywhere???
psu.pdf (30.8 KB)
No it is usually a short
