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Scott Rise
02-20-2009, 10:39 PM
Hi all. I ran into a little problem with my Jinan Artsign JSM-40 laser, so I figured it was time to de-lurk and introduce myself.

My name is Scott and I have a laser. I mostly use it for balsa, acrylic and cardboard.

The short version of my story is that one of the circuit boards in my laser burst into flames the other day. I think I can fix it, but one of the parts completely vaporized so I don't know what to replace it with. The company offered to sell me a new board but doesn't seem to want to provide me with a schematic or any service documentation.

I was wondering if somebody who owns this machine could take 5 minutes, lift up the control panel and see what the mystery part is. It's on the big board (high-voltage board?) that sits in the bottom of the case. The part (should) sit between C17 and the big yellow transformer. I've attached a couple of pictures so you can get your bearings.

Thanks in advance!!

Zachery Thomas
02-20-2009, 11:07 PM
Scott,

Trick question?

There are NO components between C17 and the transformer, just 2 wire links.

http://i413.photobucket.com/albums/pp220/zax15uk/jsm40_laser_psu.jpg

What did you find had failed, it looks like the transformer may have broken down and shorted internally - either that or something shorted the output?

Hope this helps you get it fixed, let me know if you need anything else.

Zax.

Scott Rise
02-21-2009, 6:52 AM
Nope, no trick question. That is exactly what I needed. I only have one jumper and two melted stumps in that location, so I didn't know if the one was another jumper or a capacitor or what.

I'm hoping that my problem was caused by a crack in a trace or cold solder joint or something like that where it arced for a while until it finally caught on fire and not some part that failed. I'll find out I guess. Maybe I can fix it, or worst case I buy a new board for $220.

Thanks for your help!

Zachery Thomas
02-21-2009, 10:35 AM
I hope you're right, good luck!

Is that buying direct from Artsign?

Zax.

Dave Johnson29
02-21-2009, 10:58 AM
I'm hoping that my problem was caused by a crack in a trace or cold solder joint or something like that where it arced for a while until it finally caught on fire and not some part that failed.


Hi Scott,

Welcome to the group. I think you should re-read Zax first answer again. A cracked trace or cold soldered joint would not cause that kind of failure.

You need to trace back from both of those stumps and find what is electrically up-stream of them. I am with Zax, it is most likely the transformer or osme other large component. For that amount of energy to be dissipated to melt those wires, this is no pithy fault.

In the first pic there is a brown stain on the yellow wrapping of the transformer. Looks like a "sign" to me. :D

Proceed with caution, but I would be removing the transformer from the board and testing it first. I would also be replacing that link with a fuse holder and fuse when you get it working again.

Scott Rise
02-21-2009, 2:52 PM
Zax: Thanks! Artsign referred me to a guy here in the US who referred me to the person I bought it from on eBay for the part.

Dave: Heh. "Sign". :) You're absolutely correct and I do plan on doing some troubleshooting. It was just my hope that it would be as easy as rebuilding traces. The brown marks on the transformer are from the flames next door I'm pretty sure and not the transformer itself. Visually I haven't found any other damaged parts but I do plan on spending some time with a meter to see what else is going on.

Bill Cunningham
02-21-2009, 9:51 PM
There is a old theory, called the 'electrons and holes theory'.. A side version of that theory says, that in practice, all the holes are actually filled with smoke. Astute observation has always proven the when smoke escapes from any electronic device, it's function is usually greatly diminished, or it ceases to work at all.. The things you learn over the years Eh! :D