Hi I have back to my unused K40 after a couple of years with the goal of increasing bed size and changing out the ramps board. Anyway there the laser won’t fire. I have put a pot across the PWM input set to 1.5V and shorted the interlock loop and grounded the laser fire. Nothing. What can I check. PSU has all the voltages but I don’t know how to check the high voltage or the tube itself.
Any help please.
thanks
Stay away of the hv areas. Most of us do not have the equipment/education to deal with 1k or greater voltages. Most of these will generate some 30kV. So there is really no way to check the hv, nor the tube.
I can make an assumption, when a tube goes bad the hv usually climbs high enough to cause a arc to the chassis. From your description that isn’t happening, so I’d suspect the hv power supply.
I don’t have a K40, but plenty of people here do, so hang in there and some other thoughts.
I know on my China Blue, I can remove the signal lines from the lps and the test button causes it to lase at 100% power… Don’t know how applicable this is to the K40 type supplies.
Good luck
A picture(s) of the LPS showing the input connectors and model # would help us help you.
The PSU model #.
With power on, when you push the test button down on the supply does the laser fire?
No nothing happens when I press the test button
On the side of the PSU F20150202
I have tried using one of the proximity-beeper-tester that detects live mains (240v here in Ireland). It is very sensitive but does not detect anything when adjacent to the HV cable when pressing the test button. As I am reasonably competent with electrics and electronics, is there anything I can do. If I knew for sure that the PSU or tube was dead I could replace it.
That sensor is testing for mains-frequency AC (50Hz for you, 60Hz for me). There’s no particular reason to think that it would sense correctly for the HV cable, so don’t trust it for the HV not being energized. That said, so far it does sound like the LPS is likely dead…
Is it worth even considering replacing the flyback transformer?
First, you do not want to be near the HV side of this LPS when it is hot. It outputs a lethal voltage.
Tie the IN signal on that supply to 5v. If it still does not fire then I expect the supply is dead.
I have repaired these supplies including the flyback and it’s just not reliable and economical. These supplies are consumable, they will eventually fail with normal use and they aren’t that expensive.
If for some reason you replace it and we find some other problem is the real cause it is useful to have a spare.
OK thanks for that. That’s what I’ll do.