ULS 25 28VDC power supply replacement

[Mike Ross]

I have a 1997 ULS 25E.....Pretty sure the 28Vpower supply is not functioning properly. I determined this because the service manual says:

(Paraphrased)
If the laser does fire and the fans do not come on, there may be a problem with the 28V power supply, or the stand-by mode has been activated.
To test remove the purple/white wire from the stand-by trigger. If this does not fix the problem you may have a problem with the power supply.

OK, I did this and still have a problem, darn! So I checked the power supply voltage in and out.

I have 110 volts in. That looks good.

No volts out, should have 28 V DC out.

Seems like this is a bad power supply.

I have a call in to ULS Service but its Friday night. So pulled the power supply from the frame so I can get to the data plate.

its made by Mega Power Systems

Model MG1-1G

Serial 70812121


No luck searching the web for this manufacturer, model or serial. Might have found the manufacturer in Chatsworth California but the phone # is discontinued and they do not appear to have a website.

Any suggestions? Am I missing further diagnostics? Any idea of replacement cost?

I know this is an old obsolete machine but I would like to keep it going until the tube quits.

Thank you in advance,

Mike Ross

[Mike Mackenzie]

Mike,

Are you talking about the gold box or the silver Omega power supply 48V? If it is the gold box we may be able to repair it for you if it is the silver supply we may have a used one I won't be able to check until Monday.

I will let you know.

Also we have a 25E here that we can test it on just to be sure that this is the problem. Although it does sound like the problem.

[Mike Ross]

Thanks Mike, I will email you a photo of the the suspect unit. It is silver and does say omega, although the book identifies it as 28V? I misread omega as mega.....

Greatly appreciate your assistance.

Mike Ross

[Dan Hintz]

How did you measure the output power? SMPSs typically require a minimum load before they will give you a valid output voltage... a voltmeter will not provide such a load if used on its own.

[Mike Ross]

Hi Dan,

Thanks for the advice, I am a complete novice on power supplies and appreciate the input and knowledge.

I used a volt meter, have not disconnected any wires from the unit so it should still be drawing a load?

What is used to measure the output when bench testing?

Thank you,

Mike Ross

[Constant Laubscher]

Hi I had problem with my Explorer II 100W and four of the five power supplies were bad and had to replace them. DO NOT buy from the your machine manufacturer they will charge you an arm and a leg.

I shall forward you the name of the company I bought mine from, Good service and it comes with a three year warranty.
I have tested mine and it does give you an output reading without a load at least for a while. Mine are all 48VDC
My price per 1000W 48VDC were $325.00 per unit - GCC $620

Let me know if I can help

[Mike Mackenzie]

Mike,

Looking into this and that would be a 28V supply I still do not know if I have one but if you can get one with the correct specs from constants contact I would certainly look into it.

I will still let you know on Monday if we have one.

[James Stokes]

I used this company to repair mine.http://www.powerclinicinc.com I was happy with the service and price.

[Rob Bosworth]

194 through 1997 ULS laser systems used the 28/ 30 VDC power supply. The ULS 25E and the ULS 25 PS (with the D/C excited Synrad laser) both used the single Model MG1-1G power supply. The ULS 50 Ps's used the MG1 G2 power supply.

PM me. We carry them in stock.

Oh yea, they are not cheap.

[Mike Ross]

Gentleman,

I greatly appreciate the options you have all generously provided. This forum is truly amazing.

Mr. Mackenzie, I emailed you images of the Power Supply.

Mr. Laubscher, I PM you a request for your supplier information.

Mr. Stokes, Thanks for the link, looks like a great source for Power supply repair.

Mr. Bosworth, Thanks for clearing this up for me. The voltage discrepancy was not making sense until your email. I appreciate your frankness and hope I can find another option to paying a lot. I will send you a PM and request a quote.

Mr. Hintz, sounds like you know an awful lot about this Power Supply business. Thanks for posting.

My best regards to you all,

Mike Ross

[Mike Mackenzie]

Mike,

It looks like I do have one here I need to connect it and test it to be sure it works correctly. I also need to test the cooling fans This is the reason these supplies burn out and I will bet that the fans on yours quit working.

I will take care of this today and let you know.

[Mike Ross]

Thank you to Mike Mackenzie for the advice and selling me a power supply. I am back up and running. Mike had a used model in stock and provided it at a very reasonable price.

Thank you also to Constant, nice talking with you this week. I appreciate the call to see how I was doing.

Have a great weekend all!

Mike Ross

[Brian Eberwein]

Hey guys,

I find myself in need of this same power supply for the 25E machine. It's the MG1-1G. Does anyone have advice on this? Perhaps an aftermarker replacement?

I almost thought I also needed one for my X660 and choked when I heard ULS wanted $2,100 for it. I found a place that could supply/make new ones for ~$550 per unit (2 units in the 660).

Thanks much,
Brian

[Jani Pedersen]

Hi Mike,

I thought you might like to hear of my situation - my engraver suddenly stopped on me right at the end of a raster/vector file. I was advised over the phone to check out the power levels as I had the appropriate wotsit to do it

Having given those readings it was thought that my isssue was the psu - power supply unit - and so identify in Bristol ordered a new one in for me. They were going to ship it to me but I decided I'd rather take the laser to them to put it in and ensure it was all okay.

It wasn't - it still didn't work with the new psu - Bob, one of the engineers ran a good few tests and established that it was actually the tube that was causing the issue. When the tube was disconnected the power ratings went back up ( we had four sharp clear lights on the back of the machine - beneath the panel - whereas prior to unplugging the tube from the psu we had three bright lights and one dim one )

Although this wasn't good news for us as it means a new tube we were just very relieved to have had such prompt and great help from the Epilog guys at Identify.

Is there anyone that you can contact to take you through a similar process of removing the tube / psu cables so that you can check it out then ? I'd hate to see you fork out for a new psu then find that you have to replace the tube.

Fortunately for me because mine was diagnosed 'in house' that wasn't the case here - I only have the one cost

* bows to the gods of identify *

[Dick Hatchell]

I am attaching a picture of a power supply like the one I have and need to know where on this photo to connect my multi-meter to check the 28V DC output when I have the laser turned on. My problem is with 90% power after a minute or less the laser firing gradually reduces to the point it hardly etches the material, but when setting the power to around 40% it seems to keep that power all the way through the job. The laser is a ULS 25E. Fans are working both on laser and on power supply. Used air to clean everything. Don't want to repair laser if it is a power supply problem so would like to rule that out first. Thanks for your help.MG1-1G.jpg