ULS-25E Fan Delay

[Jeff Toro]

I've searched through the forum for a response to my title, but with no luck. I've found though that it is common for some delay in the laser actually firing when turned on, so that is a relief. I bought this used laser 3 years ago and it has been nothing short of a work horse. Until recently the fans no longer come on immediately on power up. The screen comes on and the laser homes itself. I'm actually able to send a job and hit go and the head will move back and fourth, but the laser isn't firing. After about 30 seconds to a minute the fans come on and I can start engraving. The first time this happened I thought I was dead in the water with a 300 piece ceramic mug job, but fans came on and everything was good. Once the fans turn on there isn't an issue, everything is sharp and solid. I just wonder why out of the blue there is now this delay in the fans turning on when they used to start when I turned the machine on.

Can over all room temperature play a role?

thank you

[Kay Bengtson]

Check to see if the fans still turn easily when the unit is not powered. It could be that they are sticking from dust accumulation and eventually overcome that as the motors heat up. If they are full of dust, try vacuuming them out with a shop vac. Otherwise, replacement may be necessary.

[Rob Bosworth]

My guess is your 28 VDC power supply is going. The 28 VDC runs both the laser and the muffin fans. If you remove the cover over the power supply, watch the power supplies fans to see if they turn on when you turn on your machine. You could try blowing out the power supply with an air hose, to see if it helps.

[Jeff Toro]

I'll give that a try and report back

Thanks

[Jeff Toro]

I took off the back cover and blew out the fans to attempt to help, butthey actually were not all that dirty. I noticed that the two fans onthe power supply were attempting to start back and fourth until theboth started to run, but still not main fans ontop of the machine. Inoticed that there was some sort of resitor that was badly burned? (picenclosed) This was coming off of both fuses. I swapped the fusesthinking that this may have been all it was, but it wasn't.DSCN1140.jpgDSCN1141.jpgDSCN1142.jpgDSCN1143.jpgDSCN1144.jpgDSCN1145.jpg

[Jeff Toro]

Uls said to test and see if I'm getting 28vcd out of the supply. The issue is how do I do this

[matthew knott]

If had to guess (and it is a guess) i would say thay was some sort of surge suppressor, these are to protect from over voltage, they become a short circuit in an over volt situation and the fuses should blow to protect the laser. Its not uncommon for these to cock themselves overtime and crumble away so this may not be a symptom of your problem. You need to get a simple voltmeter, (walmart, ace any hardware shop), set it to volts DC and measure across the output terminals, it should be 28 volts and remain at 28 volts under full load (laser running) If that was a surge gaurd and it was running hot it would have been pulling your power supplys down so it might be ok now you have removed it!

[Rob Bosworth]

According to the ULS 25 E Service Manual, you blew out a varister.

VARISTOR
This device will burn up and short out if there is an over voltage or voltage spike situation. This will
prevent the electronics from being damaged should this occur. It is recommended to use an external
surge suppresser in addition to this protection.

[matthew knott]

Yeah thats what i thought, now its removed it wont do anything and the machine may run perfectly ok but it would be prudent to replace it as its good design practice to have one. On a side note i think i got my first laser from you Rob, it was a scriba from electrox about 12 years ago, its still going strong and started our business, so thanks for that.

[Jeff Toro]

Since this post I did the laser to fire up once w/o the varistor there. I also read the statement by Rob in the manual. I've tested the power coming in and it is there beyond the fuses, but I get nothing coming out of the power supply. Looks like I have to give ULS a call tomorrow! grrrrrr

[Jeff Toro]

ok.... well since my last post I left the machine on and just a moment ago it fired up!! I tested the power coming out of the supply and I'm getting 28vdc and the laser is engraving perfect! I have to believe the power supply is going out! I've sent a response into ULS and see what they say.

[matthew knott]

Its not common for power suplies to fail in that mode, im my experience they tend to be catastrophic failiures that dont recover, it might be a lose connection on a control cable, any 28v SMPS supply thats rated at the correct current should run the laser tube so a spare should be aesy to find.

[Mike Mackenzie]

Jeff,

I would un-plug the inhibitor cable from the power supply (your fourth pic single wire black connector) then turn on the system and see if the fans come on. If they do you should re-seat the u-step board in the gold box (Inside the gold box) as well as the connections to the mother board that is mounted to the gold box cover.

This almost sounds like a gold box issue rather than the 28V power supply.

[Jeff Toro]

ULS Response


I would double check all the connections going to the power supply and make sure nothing is loose or corroded. (Make sure it's unplugged). If everything looks good then yes, I would say that the power supply is going out. We do not stock the power supply for this system any longer unfortunately. But I have a recommendation as to who you can contact for parts for your system. The company is Access Business Solutions. They buy used lasers and sell them whole or as parts. Their website is www.usedlasers.com and his phone number is 715-386-8021.

[Jeff Toro]

ULS Confirmed the power supply is in fact going on the machine! They of course no longer stock a power supply for my machine, but pointed me towards usedlaser.com. They have them in stock and ready to ship @ $800.