Can someone identify this component/help me repair this laser power supply.

[AlessandroAU]

Hi all, I bought a DPPS laser module from ebay quite awhile ago. However it was DOA and the seller was most unhelpful (I didn't actually get a chance to power it up untill months after the sale)

200mw 532nm DPSS laser with Analog+TEC+Power Supply | eBay

I did some probing with a DMM around the circuit and managed to have it power up when I probed the solder pads of the component listed as V1 so I figured it was merely a faulting solder joint. However I managed to foolishly short the component whilst probing around it and promptly exploded.

I was wondering if anyone else had used these modules or similar and could help me identify the component so that I could replace it.

 

[bweasel78]

are you talking about that transistor (black upright rectangular compononent)? if so, it should have a parts number on it. I am by no means an expert (at all), but it looks to me that you have killed the transistor which rapidly switches the power to that induction coil to produce the 12volts for the driver. you could use another power supply. or swap that transistor out for another. should be relatively easy to find another power supply but alot cheaper to replace that transistor.. IF that is the problem. you will probly find people will need more info to diagnose the problem. (is it the transistor?)

 

[AlessandroAU]

Yeah, unfortunately when the component failed it blew off the entire front and any indication of a part number. Are you sure the lower half of the circuit runs off 12v?

 

[Hiemal]

There's two halves to a switching power supply, the high voltage side (where the 120 vAC is turned into 170 VDc, then into the transformer) and the other low voltage side, which is whatever the output voltage is.

Now there's a problem; you don't know if it's a MOSFET, or a BJT... how old is the power supply? Can you tell what package (the casing) of the transistor is? A better picture of the front and back of it would help me identify it.

If it's a TO-247 case, then it's most likely a MOSFET, and almost any MOSFET rated over 600 volts ought to work fine.

An IRFP460 would make an excellent replacement, if it's a MOSFET.

 

[bweasel78]

my advice would be to listen to "le quack" it sounds like he is more knowledgable on the subject than i am. i understand the basics, but when it comes to recomending alternatives i dont feel confident enough... i hope you can get one sorted

 

[Cyparagon]

That would be the chopping transistor. An over-simplification: It cuts the rectified mains into smaller portions that are averaged via filters to a lower voltage. It will indeed be a MOSFET. It looks like a TO-126 package to me. As stated above, something in the range of 400-600V rating should be fine.

 

[AlessandroAU]

The package seems, unusual. it has 4 pins with the fourth being NC. Here is a better close-up of the chip. Thanks for your help guys

Edit: It is smaller physically than a TO-247 case. It looks exactly like a TO-126 case but with an extra lead.

 

[Cyparagon]

hahah, I see now. It's just a TO-220 with it's belly blown off.

One guess (from benm) is that it is a packaged switchmode IC (Q usually denotes transistor and U usually denotes IC). The missing trace might have been blown apart too? Either way, it is probably a better idea to replace the whole thing. These devices tend to fail catastrophically - they take several components with them, not all of them obvious.