KH-7050 Laser dead

[Josh Bern]

So today I was running my KH - 7050 laser engraver, and it was running for a couple of minutes at about 50% power when it just died. When this has happened before, it was usually just my outlet, so I tried the outlet with other devices and it works just fine. Therefore, the problem is within my machine.
I found that the emergency stop switch was disconnected somehow, and I reconnected it but still nothing worked. Then I replaced the fuse under the power port, which did something. Now the power supply fan turns on and the laser light (LED) works. That's about it. The screen does not work and there is no response from input. Also the outlets in the back that power the blower, water, etc. are dead. There are no status lights working near the PS. Could it be the power supply? Or is it another more hidden fuse?
I found one other person who described the exact same symptoms but their question was left unsolved. I'm hoping somebody can help me solve this issue. I was in the middle of an important project so please answer ASAP.
Any help would be fantastic and greatly appreciated. Thank you!

[Pete Cyr]

Sounds like the power supply. There should be a fan or two and some lights on the pwr supply. If non are running ...I would get a new power supply. However, be sure you have power in the outlet the the laser is plugged into.

[Gene Uselman]

Are you fairly new to this laser? The wiring on these machines is often suspect- especially the outlets on the rear. I would use a plugin strip on a separate circuit for the accessories. Gene

[Josh Bern]

Thank you for the quick response but I don't think it is the power outlet. Especially since I have had that problem before and since the outlet works. The fuse blew and therefore I think something internally happened. What do you think? Thanks again

[Doug Fisher]

You have conflicting information in your posts that make it hard for us to determine what has happened and the current state of affairs, so it is hard to advise.

>> Also the outlets in the back that power the blower, water, etc. are dead. <<
then
>>since I have had that problem before and since the outlet works.<<

I wouldn't just start throwing parts at it though. I would start over by getting out your multimeter and confirming the functionality of every switch, fuse, outlet and both outputs of the low power supply. Google for the video on how to check the high voltage power supply by using the test lights and buttons (on most, but not all high voltage power supplies).

[Josh Bern]

Sorry about that. I understand now. To clear things up, the wall outlet works normally, but the three outlets on the back of the machine do not work. Thanks.

[Jeffrey Aley]

So today I was running my KH - 7050 laser engraver, and it was running for a couple of minutes at about 50% power when it just died. When this has happened before, it was usually just my outlet, so I tried the outlet with other devices and it works just fine. Therefore, the problem is within my machine.
I found that the emergency stop switch was disconnected somehow, and I reconnected it but still nothing worked. Then I replaced the fuse under the power port, which did something. Now the power supply fan turns on and the laser light (LED) works. That's about it. The screen does not work and there is no response from input. Also the outlets in the back that power the blower, water, etc. are dead. There are no status lights working near the PS. Could it be the power supply? Or is it another more hidden fuse?
I found one other person who described the exact same symptoms but their question was left unsolved. I'm hoping somebody can help me solve this issue. I was in the middle of an important project so please answer ASAP.
Any help would be fantastic and greatly appreciated. Thank you!

It is challenging to help you because each machine is wired a little differently.
I'd get out a voltmeter and start tracing the wiring starting with the wall socket. I think you said you have voltage at the wall outlet (120VAC). Confirm it with the meter (that'll also help you know that the meter works )
Next open up the panel where the power cord comes into the machine. Measure the voltage there. I expect you'll have 120VAC because we know the power does get to one of the two power supplies.
Now follow the wires. Does the power go from there to the EMO [Emergency Off] switch? Or somewhere else first? Wherever it goes, follow it and measure.
Eventually, you'll find where the voltage stops.

Here are my semi-educated guesses, based on what you've said:
1) The outlets on the back of the laser are "dead". They may each have their own fuse, or else the EMO switch is not passing current to the rest of the laser.
2) No display, etc. Measure the input voltage to the low-voltage power-supply (usually a small silver box with lots of holes). Do you have 120VAC going in? Change your meter to DC and measure the output terminals. Any voltage coming out? If you've got 120VAC in, and 0V out, then you need to find a fuse or something on the low-voltage power supply. Or replace it. That low-voltage supply powers the RuiDa controller, the display, and probably the steppers and the red-light laser-pointer.

Good luck!

[Josh Bern]

Thank you for all the information.

In case it was not clear before, the only working parts are the fan on the right side door and LED work light near the bed. Nothing else is on. That’s why I think your option #2 may be right, the small power supply.

Do you know of the location of fuses other than the one directly under the plug for power? I already replaced that one and it helped start up the fan and work light so I’m thinking there are other, more hidden, fuses in the machine. My only problem is that I do not know where they are located. Maybe in the small power supply?

If anybody has an idea, please let me know. Thank you!

[Hank Morgan]

But you said the rear outlets don't work either?
That sounds like a bad switch or wire loose, not power supply.

You said a wire came loose from the emergency stop switch and you replaced it? And a fuse? Tell us more about those things.
Is the E-stop switch bad?
Or maybe 2 wires fell off, but you only found one and put it back?

[Josh Bern]

It's a bit confusing because I went through a multi step process trying to fix the problem. I will try to simplify it into my thought process and steps in the order that they occurred.

1) Laser shuts off during print. Power was at 50% and running for less than 5 minutes. Nothing responds. No power to laser, screen, control panel, etc.
2) Tested the wall outlet to see if I switched the breaker in my house but the outlet was working fine. Concluded that it must be the machine.
3) Looked to see if the emergency stop was somehow pressed. Played around with that for a little bit as it felt a little loose. It was not pressed and therefore everything should have worked. I moved on but this becomes an issue later in step 6.
4) With the two most common issues put aside, I did some research and found the fuse located under the power cable port (on right side of machine). The fuse was completely blown and black. Replaced the fuse.
5) I expected everything to work after replacing the blown fuse, but nothing again.
6) After opening the right hand side door with all the electronics, I discovered that the e-stop switch had been disconnected from the external button. I concluded that it had fallen off when I was moving it around in step 3.
7) Somehow I popped the e-stop switch back on the button and it felt in place again. This brought me to my current situation. Although the e-stop was now fixed, I believe the fuse was the real issue and the e-stop was just my mistake. With the fuse replaced and the e-stop in the correct position, I confidently try once more.
8) Turned the machine back on and hear the quiet sound of a fan! Unfortunately, that was the only thing moving. The fan located on the right hand side door. I tried the RUIDA controller and other buttons but nothing responded except a simple work light and the fan.

AND here I am.
If you have any other questions that could help solve this, please ask! Thank you