burnt +5v rails

J

jamestime88

[H]ard|Gawd
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Dec 10, 2003
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my computer was having gradually worse stability problems until it wouldnt start anymore. i took it apart to diagnose the problem and noticed that the red (+5v) connectors are burnt and brown on my ATX 20 pin connector.

the power supply is a 400w antec smartpower, has never been opened or modded, and is probably 1 year old. up till maybe 3 weeks ago i had no problems with my computer whatsoever, and i cant think of anything i did to cause this.

i put in a new power supply, but it's a generic 450w and i don't want to use it for long. what caused the +5v lines to burn? is there anything i can do to prevent this from happening to the next board?
 
Or, you could just get a new Molex with new connectors and replace the old one. Sounds like you had some resistance or loose contact issues in that plug. Just make sure the new contacts are secure.

Luck
 
Bad connector. If the burnt pins were caused by a power supply failure, then chances are your computer wouldn't be working right now.

Make sure the pins in your motherboard's ATX connector don't have any carbon on them - if there is any, scrape it off with a jewler's screwdriver or something. If you've got good soldering/desoldering skills and you're feeling a bit adventrous, it might be worth replacing the connector entirely.

And again if you're feeling adventrous, you could try picking up an ATX extension cable and a load of heatshrink, and splice a new ATX connector onto the Smartpower. It's a good supply.
 
i dont know if it's worth it to me to resolder it, i'm not very skilled. wouldnt the power integrity also take a hit if i resoldered the whole thing?

could i possibly RMA this to antec? i dont have any of the original paperwork or the box.

maybe a year ago i had a different computer on the same outlet as this one is now. the power supply "popped" and it took the motherboard with it. is there a chance that my power is bad? worth getting a UPS?
 
jamestime88 said:
i dont know if it's worth it to me to resolder it, i'm not very skilled. wouldnt the power integrity also take a hit if i resoldered the whole thing?

could i possibly RMA this to antec? i dont have any of the original paperwork or the box.

maybe a year ago i had a different computer on the same outlet as this one is now. the power supply "popped" and it took the motherboard with it. is there a chance that my power is bad? worth getting a UPS?
Click to expand...

An RMA will require “Proof of Purchase”, most companies require that at a bare minium.

No, you won’t hurt the integrity of the PSU with that type of repair at all.

A UPS is always good, no matter what.

Luck
 
Bad power didn't cause that, antec just put a flaky ATX connector on their supply. The connector ended up having a high resistance, and since your computer pulled a fair bit of current through this resistance, this overheated and burned up the connector.

It's a common occurence - i've seen it happen in a few computers, and in a surprisingly high number of car audio installations. :D
 
The -5VSB on my Antec Truepower 430 died on me and I RMA'd it back to my vendor which in turn RMA'd it to Antec. It took like 2 months though!

This was only 6 months though, compared to your one year. I don't know how long the terms of your warranty is.
 
i bought a 20 pin atx extender from directron. i'll go to radioshack sometime this week and pick up the shrink wrap. hopefully everything goes well.

any tips/suggestions?
 
jamestime88 said:
i bought a 20 pin atx extender from directron. i'll go to radioshack sometime this week and pick up the shrink wrap. hopefully everything goes well.

any tips/suggestions?
Click to expand...
Get *lots* of heatshrink - you'll need about 2 feet of it, and you'll want it to be 3/16" diameter before shrinking. Get some small cable ties too.

First hack the connector off your power supply, but keep it around so you know what color goes where. Every extender I've ever seen hasn't kept the ATX color code, so you'll want to make sure the same colors from your supply are ultimately going to the same pin on the ATX connector.

After you do this, clip the cable ties off the existing power cable. Put every piece of heatshrink onto the ATX cord before you begin soldering, because you're guaranteed to forget at least one piece if you don't - and push it up the cable by the power supply before you begin so you don't accidentally shrink the heatshrink with the heat of your soldering.

Twist the wires together well so you don't get any sharp pointy strands coming from the splice after you solder it, which can poke through the heatshrink. If any happen, flatten them with a pair of pliers so they won't poke through. You'll want to strip about 5/8" on each end.

A butane lighter is probably the best thing in existance for shrinking heatshrink, but careful not to burn or melt the heatshrink.

Once you're done, install the supply in your case, neatly arrange the ATX wiring where you want it, *then* put the cable ties on it nice and tight. This way the harness will be perfectly formed to your needs.
 
Offset the cuts so that if you line up the wires next to each other, the new solder connections aren't all on the same line. That is beneficial in a couple of ways -- less stress on the joints if they are pressed close together, less chance of shorting if something rubs (not really going to happen on this job though I would think), and it looks good.
 
molex.JPG
what do i do? the antec power supply has 22 wires, and the replacement only has 20.
 
If you have two wires from the PSU to your new Molex just solder the two wires to the matching one on the Molex. They were connected together to start with; you’re not changing that at all.

Doing good so far,

Luck
 
I'm almost done, I'll post the pics of the finished job later tonight.

what do i do with shrink wrap that i overheated and melted part of? could i just cover it up with some electrical tape?
 
ground the Green socket to any of the Black sockets and hook it up to an old drive and fan first ;)
(a paperclip will do, its just a 5V signal, if you have calluses you might not even feel it :p

if nothing goes boom (and the fan spins) then hook it to the mobo

the drive is to give it enough load to send the power good signal and startup

for extra brownie points throw a multimeter on it before attaching to the mobo
+12V....11.4V to 12.6V
+5V......4.75V to 5.25V
+3.3V...3.135V to 3.465V
anywhere in there would be OK, they wont be all that accurate without a real load on them but they also shouldnt be outside that
then retest after youve attached the computer

for your eagle scout badge youd then adjust the pots internally
(I think you have already voided the warranty on that :p )
to calibrate the rails to the actual baseline voltages
+3.3V +5V and +12V ;)

Good Luck
 
thanks for the tips ice czar. i have a CD-RW drive hooked up to it right now and it seems to run fine.

i need a little help with the multimeter though. i'm not certain how to use it

edit: it's an analog multimeter.
 
those are pretty damn close considering its not under a decent load


regarding an anaolg multimeter as opposed to a digital
it might not be Auto-Ranging so you might need to set the range
probably to 10.00V then you have to read the needle instead of having a big digital readout
that too might have different scales youd read off the scale you selected

your still attaching the probes the same way, the black lead to ground the red to the rail your testing and reading the results ;)
 
jamestime88 said:
what do i do with shrink wrap that i overheated and melted part of? could i just cover it up with some electrical tape?
Click to expand...

I've had electrical tape unravel. :(

I found that there are three types of heatshrink. The shiney black type is vinyl and melts easily, but the dull kind that's charcoal grey or other colors, including translucent white, and the clear type with a bluish tint can even withstand a few seconds of direct contact with a soldering iron. Even hardware stores and home centers sell the latter two in 3-4-foot lengths.
 
I use that dull grey\black kind ^
havent used the others

absolutely detest electrical tape
the damn gum is a mess eventually
 
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