Busted PSU?

[DRJ1014]

2 Days ago i had my computer over at my friends house. When I brought it home and hooked it all up and hit the power button the lights on the motherboard cpu fan psu lights and the front thermaltake light flashed quickly then went off. thishappened about 4 times then it finally went on. I didnt think anything of it that it was just the stupid wireing in my house. but today it happened again. I sat there for 30 min trying to get it to turn on. I noticed white lights coming from the psu but it had blue lights in it so i knew somthing was sparking when i hit the power. I changed PSU's to an antec 350 smart blue (changed it from a thermaltake 410watt) and it fired right up.

Ok now the newb questions.

Did i blow my PSU? It gets power to the motherboard lights when its off. Or could it just be somthing and it just had to sit?

 

[larrymoencurly]

Did i blow my PSU?

How is that relevant to the topic?

A good PSU shouldn't go bad even if it's shorted, but I don't know if Thermaltake is that good. I'm guessing that the white flash was the fuse popping, which likely means that the high voltage transistors popped, too. I've seen some PSUs where the wire leads sticking out the bottom of the PC board came really close to touching the case, and I have an old Antec where all the leads were bent over and some seemed to be shorting (got it to working by clipping off lots of leads or prying them up).

Have you tried shorting the green wire on pin 14 to any of the black wires (like pin 13 or 15)? That should make the PSU fan run, indicating that the +12V is working at least partially, but if you measure the voltages don't be surprised if they're off specs because many PSUs don't regulate accurately without a load.

 

[Ice Czar]

It gets power to the motherboard lights when its off.

http://hardforum.com/showthread.php?t=761614

The ATX motherboard specification maintains +5VSB power to the motherboard
unlike PC/XT, AT, Baby AT and LPX form factors that employed a manual switch to turn on the power to the motherboard, the ATX form factor employs a "soft power" scheme
allowing software control of power, allowing the OS or other ap to turn the computer off, it also allows wake on LAN or Wake on WAN. Since there is a low level of power supplied to the board at all times, you need to address this whenever your swapping out components

the ideal solution is to unplug the power supply from the socket then ground the case with an alligator clip to a seperate ground point and use a wristrap to ground you

the alternative method is to turn off the PSU with its own switch
reliable only if the board has a 5VSB LED indicator on it
at which point you know the board is unpowered, yet the case is still grounded via the AC Socket

the alternative method if there is no switch on the PSU and LED mobo power indicator is to unplug the PSU from the wall socket, then disconnect the main power connector and plug the PSU back into the AC Socket, where once again you have the case grounded

keep in mind that typically the PSU physically contacts the case with a metal to metal contact, at least in the past, and would have at least some contact via the screws, but these adys with painted cases and supplies, some augment that with a grounding strap for the PSU itself (very typical in server supplies where they take no chances with contact)

and religously touch a bare metal surface in the case to ground yourself when swapping componets (this is very typical in here with enthusiasts)
but all in all wristraps are cheap and so are alligator clips and a bit o wire
a grounded work pad is also a good investment, as is being aware of how large a role the lack of humidity has in ESD events, especially in Winter when hot air heating desiccates the moisture out of the air

(see I live on the Rocky Mountain High Dessert Plateau, where its already dry and in Winter with central home heating I humidify the environment when working on components)

and adding to larrymoencurly's point about shorting the green to black
without a load some wont even turn on (no Power Good Signal gets sent) so adding an old drive or other resistor is a good idea

depending on the supply there could be a number of fuses involved
you can pop the top to see what there is to see
from burnt PCB and traces to obviously borked components

like this thermal take butterfly

 

[BillR]

Hey, that PSU is blowed up