Wow, what went wrong here?

S

starhawk

[H]F Junkie
Joined
Oct 4, 2004
Messages
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(Apologies for the display size of the images -- if it's a problem, I can shrink them.)

So I have one of those eBay "molex" power supplies. You know, 2.5a on each line, for powering drives and such for testing purposes. Like this...

dmFYTSR.jpg


I have two. I got one with a USB to IDE/SATA adapter, from the typical source. I bought a second one because my external DVD drive at the time was acting up, and I had every intention of replacing its power supply (which had gone from a 5v/12v supply to a 5v/24v supply :eek: oops!). That never actually happened.

Well, today, one of the two supplies blew. Ironically, it was plugged into the remains of that external DVD drive -- or rather, the drive itself. (I still have the drive, its USB converter/controller card, and its defective power supply.) The drive was destroyed, sadly -- my one and only SATA optical drive. Whoops. (It now reinitializes itself upon pressing the eject button.) I was lucky that the USB IDE/SATA adapter (the eBay one -- the converter PCB that came with the drive has a weirdass connector) was just fine.

As I plugged in the power supply to its wall cord (having hooked up everything *except* the USB adapter's computer end) I saw a bright red light, just for a second or two, from inside the drive, through the label. I thought it was odd, but tacked it up to an internal optical "is there a disc here?" sensor of some sort. (I now realize what it was, and why I had an eyestrain headache later. That's one hell of an overvolted diode!)

Then I heard a sizzle and some smoke came out of the adapter. I hurriedly unplugged it, and felt it to see if it was hot (it wasn't, which was odd). Out on the porch it went, just in case it was interested in venting other things.

Later I got the supply apart, destroying the case completely in the process (dear China: please use screws, not epoxy -- but if you must use epoxy, use something that actually bonds!). Yep, looks like it made a mess. Here's pix of the carnage -- lookadatt capacitor! (As a note, the component that looks like a small light bulb is in fact the fuse. Yeah, wow.)

JsVK55R.jpg

Xg0H2bx.jpg

beIeHcu.jpg


So... what (probably) happened first? Did the capacitor pop, and then fry the switching transistor (izzat a MOSFET?) -- or did the transformer short itself to bits, pop the capacitor, and fry the transistor? Whodunnit?
 
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LOL! Okay, I'll resize and repost them. ~300dpi straight off the camera is apparently bad for your health :p

Sorry 'bout that!

EDIT: massive pix problem fixed.
 
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Looks like a cap on the secondary side went bad--see that bulging cap? That can lead to all sorts of nastiness, including blown switching transistors, blows fuses, and blown loads (like your dearly departed drive).
 
That cap was the first thing I saw. The question is: did the cap itself pop, and destroy the rest, or did something upstream pop it (like the transformer shorting out or something)?

All I know is, that cap had quite a tortured route to the afterlife :p
 
Thanks for posting that up I had been looking a getting one of those kits off ebay to test older drives and run and internal optical if I needed. Now i'm thinking I should get a bit better AC adapter and just wire up my own connections...
 
To be fair, it took about at least a year and a half of good steady service for that to happen. I'd buy another if I had the dough...
 
Is that liquid corrosion around the solder near the power plug, or just burn damage?
 
Looked like burn damage to me... but TBH I've no idea, and this particular expired contraption has long since gone to the eWaste bin at the dump.
 
just a note on these glued up plastic cases

Put the item in the freezer for a couple hours, then take it out and right away tap vigorously all around the seam with the handle of a screwdriver or a miniature ball peen hammer.

Works on radio battery packs also
 
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