Laser power supply test button LED not working

[jgecik]

After my last tube cracked months ago, I recently replaced the tube and have gotten everything wired up. The problem I'm having is that, when activated, the laser doesn't turn off until the reset button on the DSP is pressed or the power is otherwise cut to the machine.

When I press the "test" button on my laser power supply (Jupiter co. ?LD40S 40-60W), the little light doesn't come on. I'm wondering if the problem with my tube not shutting off could be with my power supply.

Any suggestions or thoughts are appreciated.

[parsifaldruddle]

Does the laser fire when you press test or only when activated via the DSP?

pars

[jgecik]

The laser does not fire when "test" is pressed on the LPSU, only when I press "Laser" on the DSP.

[parsifaldruddle]

EDIT:
I tried to keep in mind that the DSP does start the laser and the DSP reset does disable the laser. I think, though, I got off on a tangent down below. My understanding is that the DSP normally controls the laser with PWM out of it's 'Laser1/Laser2' TTL terminal AND a LOW on the 'G' terminal (which subsequently runs thru say the water flow switch, door switch, key switch, etc. and to the 'G' terminal of the PS.

If the DSP is at fault, it should be at one or both of those terminals. Is the laser firing at 'full power' (plus or minus any analog current control pot)?, because it sounds like the DSP 'G' is latched low and 'TTL' is either not stopping PWM pulses or is latched fully on. Hitting reset should bring 'G' high and 'TTL' to whatever is 'OFF' for your system - High or Low. Since it does stop firing when you hit reset , your wiring and PS should be okay. The fail to fire when 'TEST' is pushed may well be a second, separate problem. I'm not sure if it ignores completely the WP/W/P input - bypasses it - or it needs it and the DSP is not providing it - which would put the problem back on the DSP.

Everything below was written earlier. I was going to delete it, but thought there might be something of use there, although probably NOT for this specific problem. Folks usually find out I'm not the sharpest marble in the shed eventually anyways, so I left it.

Well, we have the controller, wiring or the PS. No fire with the PS 'TEST' button smells like the PS to me. Double check the wiring - it's easy to get something wrong and miss it repeatedly. I try to get others to check my work; I might check, dbl check, triple check and not see the problem. Don't forget to pm or email LO - sales has always been quick to respond for me.

If the wiring is definitely good, that would leave the PS in my guess - the test button is 'local' to the PS and doesn't work, as is the TH/TTL H and TL / TTL / L circuitry. If you have a manual current adjust pot, adjust it down or disconnect it. You might try testing any 'kill' switches you have - water flow, door, laser enable what have you. From the PS wiring diagram here download/file.php?id=32,

The water protection for the PS requires a 'low' on the WP/W/P terminal - lift that wire (DO NOT DISABLE YOUR PUMP), if the laser keeps firing, it's the PS (we just took the wiring and DSP out of the loop for that portion of the circuitry). If it dies, at least the WP portion of the PS circuits works. Connect it back up.

If lifting the wire on the WP/W/P terminal does not disable the laser, the problem is internal to the PS, because lifting that wire is the same as having your water flow switch, door switch, or key switch go open during normal operation.

A LOW on 'TH' / 'TTL H' should disable it if your system uses that input for manual or PWM control.

A HIGH on 'TL' / 'TTL L' should disable it if your system uses that input for manual or PWM control.

Which ever your system uses (probably TL/TTL L), disconnect the line and provide a HIGH or LOW as applicable thru a 1K~500 ohm resistor to limit to the terminal to 5ma~10ma (should be safe for 'TTL' inputs).
The PS may already have pull-up or pull down resistors inside - i don't know - so just lifting the wire from the terminal may suffice. If just lifting the wire has no effect disabling the laser, try with the resistor - if neither way disables the tube, the problem is internal to the PS.

If those tests DO disable the laser, then it's a wiring or controller problem.

It's helpful to know what power level the laser continues to fire at when it should be disabled, and along that line - do you have a manual current control pot hooked up? If, when it does not disable, you can vary tube current with the pot, that tells us that either TL or TH is either in solid (constant HIGH or LOW as applicable) from the controller OR inside the PS past the input circuitry OR it's pulsing at such a high rate & width as to appear constant and allow analog control. An o-scope connected to the TL or TH input to the PS would be very handy

Disconnect the TTL output at the controller - still firing - (this eliminates the controller as a cause) power supply trouble or wiring short.
Leave the controller disconnected and this time disconnect the line at the PS terminal (this eliminates the wiring as a cause)- still firing - PS trouble

I'm sorry if this is a bit jumbled - only ran my 40w tube for maybe an 1/2 hour under a minutes a time almost two years ago, so I am admittedly rusty.

IT WOULD BE PRUDENT TO DOUBLE CHECK ANYTHING I'VE POSTED WITH SOMEONE WHO IS CURRENT AND ACTIVE AT TROUBLESHOOTING CONTROLLERS AND PSs,
and to review any drawings, schematics or diagrams for your particular setup before proceeding - last thing I want is to cause anyone's equipment or person harm
due to bad advice or procedure I might give.

I sincerely hope it is a small and simple problem giving you grief,

Pars

If this was a little rambly, I was flipping back and forth thru drawings and diagrams on the screen and I apologize.

[jgecik]

Thanks for your help. It is a little rambly, but that's a good thing; the more information I can get, the better.

My wiring is set up per the wiring diagram that's bee floating around the form for forever.

I'll try the trick with the resistor, but given that my LPSU isn't showing any LEDs, my guess is that it's a problem with the LPSU.

No, I don't have a manual potentiometer. I was going to adjust the three potentiomenter-looking screws inside my LPSU, but didn't, thinking it would be best to test the current in case I didn't need to make any adjustments. I did take the LPSU apart to look for the native pots, could that have done something? Or was it just having the LPSU sit around inactive for five months?

I disconnected the wire at the TTL terminal on the DSP: Still fired and stayed on
I disconnected the same wire at the LPSU: Still fired and stayed on.

So, conclusion: It's my LPSU. My guess is that I'll need to replace it.

Thanks again, Pars.

[parsifaldruddle]

You're quite welcome! I hope something I said was of use.

So, where're you at now with it?

I took a break from laser stuff for a day - had to butch some wood the old fashion way with a saw. Now I'm figuring bolt locations for those two rails I have to add for shelf edge support on either side of the z table. this should have been done before the z table went in and all that. live-n-learn.

Pars

[jgecik]

Well, right now I'm at a standstill. Do you think a replacement laser power supply is in order?

Yeah, I've come to the conclusion that modding a K40 was an enormous mistake. I haven't even bothered mounting my Z table, it kinda just sits in the machine.

[Tech_Marco]

Well, right now I'm at a standstill. Do you think a replacement laser power supply is in order?

Yeah, I've come to the conclusion that modding a K40 was an enormous mistake. I haven't even bothered mounting my Z table, it kinda just sits in the machine.

Hey Jgecik:

I need to cheer you up. When it come to a problem, let's solve face it and solve it. Remember that the laser machine isn't a simple low tech stuff but somehow a mixture of high tech + low tech.
The issue you have may be just as simple as a wiring issue or just a fault power supply. Everyone is going through the same path to learn new things. We always say "No pain, no gain!"
Once you finished the upgrade, you will learned a lot about laser machine and you can move on for a bigger system. It is fun, and it can be profitable! Trust me, you can do it. There are a lot of folks have ground zero tech skill and I heard a lot of success stories. It is just too many to tell and you can feel how happy they were when they told you about the story. So, solider, crank it up and move on. Me and other folks here are standby to help you. We don't charge you so feel free to post your question!


Regards,
Marco

[jgecik]

Marco,

Thanks for your reply. I'm one of the success stories you mention, actually, and the community has been a big help. My complaint was mostly about how useless the K40 is after replacing just about everything except the XY gantry in the machine. Why not spend a little more money up front instead of putzing around? But, you live and you learn.

I've followed through on Pars's recommendations to little success with this particular issue (everything else seems to work just fine).

My only question is do I need to order a new laser power supply?

[Tech_Marco]

I don't have that kind of power supply on hands so I don't know if it works or not. I did try a similar PSU before but the result wasn't good and it burned after a while. But that one was not identical to yours but an original (old type) for K40 from Shenhui. I have to find a 'signal' return path in order to drive it. May be due to incompatible issue, the PWM output from the DSP got damage. So, I dared not to try it no more. I asked folks who no longer need that PSU after an upgrade to donate it and let me try it but got no response. The true is that I won't spend $100 to buy back as it really cost $30 or around for that kind of power supply

Marco

[jgecik]

Marco,

I appreciate you trying.

Looking at my order history, my LPSU is about two years old. I'm on a deadline for a job, so I'll order a new PSU if I can't get it squared by the 30th.

I have a 45w tube. Would this be an appropriate LPSU? http://www.lightobject.com/40W60W-PWM-C ... V-P72.aspx

Also, where in that power supply is the potentiometer for adjusting the current?

[parsifaldruddle]

I'm with Marco on this - no pain, no gain. I don't think you made a mistake to upgrade - not in the least. When this is solved, you'll have a better machine and you'll know a lot more about not only your equipment, but others' as well.
This is a temp setback / holdup. I'm having them on my build as well - oops this and dangnabbit that - shoulda coulda-oughta-woulda. I try to stay calm and chuckle thru it.
So -
Gene Kranz: Let's look at this thing from a... um, from a standpoint of status. What do we got on the spacecraft that's good?

Tube - GO.
Drive system & PSs - GO.
DSP - GO - questionable
HVPS - NO-GO - questionable.

We have a TEST button on the PS that does not fire the laser.
We have a LASER button on the DSP which does fire the laser.
When fired, the laser does not shut down until the DSP is reset, or power is interrupted.

So, it appears to be the PS on two counts: 1) Non-functional local TEST' button and 2) 'Latching' in the 'ON / FIRE' condition.

This is my 40wPS:



The highlighted area on the internal image is an epoxy block and that no doubt contains the control logic for the PS.
While you could get in there and replace a faulty component, in my experience it is not worth the effort - it
would be a messy messy job with a questionable outcome.

It would be nice to see the signals on the PWM and TTL terms of the DSP to see if they're hanging in the ON state when you
release the LASER button and before you hit RESET. Failing that, I'd replace the PS next since the DSP is appears to be
functioning for the most part, it is unlikely the wiring could cause this particular problem and the PS is where the faults
manifest. Pull the trigger, do the deed and CRANK IT UP!!

While you wait for the PS, you can get that z table in !

It's gonna work,

Pars

"Gene Kranz: Let's work the problem people. Let's not make things worse by guessing."

[jgecik]

Okay, thanks, gents. I'll order a new PSU when i get the chance.

While i'm getting help, i'm having trouble with my DSP.

When i try to load a program from LaserCAD, the cut path loads fine, but the speed and power settings on the LCD panel seem to override the settings on LaserCAD. For instance, if i draw a 30mm circle to cut at 99% power at 10mm/s and load the program to the DSP, the machine will cut a 30mm circle, but will do it at 45% power at 50mm/s (the settings i key directly into the LCD panel). This didn't happen when i last ran the machine a few months ago.

Any clue what's up with that?

[AndyKunz]

Go to the Settings on the panel's Menu button.

One of them (I forget the name right now) means "panel settings trump file settings" vs. "file settings trump panel settings."

You need to set it to honor the file settings, that's all.

Andy

[jgecik]

Andy,

I think I found what you're referring to. It was called "Soft layer params" (as opposed to "LCD params").