Safe to desolder 20-pin connector from motherboard?

SometimesWarrior · Post by **SometimesWarrior** » Sun May 04, 2003 1:23 pm

I suffered from a PSU meltdown last week, and the red wires going from the PSU to the motherboard burned up. They melted the PSU power connector to the motherboard, so there's no way to separate the two; the plastic is fused together. Thankfully, the computer seemed to shut down gracefully after I smelled something burning, so I think all my system components are fine, besides the PSU, which is getting replaced.

I want to desolder the 20-pin connector from the motherboard so I can either a) continue yanking at the PSU connector without possibly ripping apart the motherboard, or b) replace the motherboard connector with one from another, spare motherboard (or with a new connector entirely; anyone know a good place for me to purchase such an item?)

Is it safe for me to desolder the motherboard connector? Or will I need to be very careful not to overheat/burn anything on the motherboard? I've done a little work with the soldering iron, but not a whole lot.

Thanks for any advice!

dukla2000 · Post by **dukla2000** » Sun May 04, 2003 2:24 pm

I presume you have an AMD CPU or older Intel?

And from what you say it is multiple wires melted?

Because Red is the +5V, and is the line that is probably used for the CPU voltage regulation on the mobo. So you need to fix it perfectly - good soldering would be fine but a hack (your solution a is in this category) is not good enough. I would try cut the connectors apart with a sharp blade and/or even cut away the mobo plastic completely- it is easy to live without the plastic socket on the motherboard as long as you pay tripple attention to the plug orientation in future. If you are lucky and it is only the plastic that is melted together, then make sure you clean the contacts on the mobo really well before using a new psu (to ensure best possible connection).

However, the pins may have also welded to the sockets, in which case I figure a new mobo is recommended. There are 4 +5V connectors in the ATX block, and they are not adjacent so if all 4 are 'welded' you dont have an option to solder +5V wires and use the connector for the rest. The only option would be to desolder all the 'welded' pins and get new pins to solder in, but you will need the correct spec as any connections here that are not up to standard will arc, weld, melt and fail really quickly due to the high current needed.

The other vote for a new mobo - do you know why things started melting? Could actually be a mobo fault (that was causing increased power drain without an OS crash) in the first place.

SometimesWarrior · Post by **SometimesWarrior** » Sun May 04, 2003 11:03 pm

Thanks for the suggestions, dukla2000. I am running a Tyan Tiger dual-CPU motherboard with two XP1600's. According to powergyoza's current-draw measurements for his identical motherboard, I am indeed draining a lot of power from the +5V lines, almost 30A. One red wire (the one closest to the center of the connector) made a burn mark on the outside of the motherboard connector. The other wires were not so bad; only a little insulation melted. No damage is visible on the underside of the motherboard, nor on any other components.

I'm not sure what could have caused the meltdown, because I had made several modifications within the last month: a new GPU heatsink, a suspended hard drive, and a PSU mod (which actually lowered exhaust temperatures). On the day of the meltdown, I had attached a couple more NMB 0.06A fans to the motherboard, thus going from four attached fans to six and filling all the fan adapters on the motherboard. Perhaps it was a bad idea to run so many fans off the board? Two of them were also run through Zalman Fanmates.

I'll continue to cut away at the connector and see if the motherboard pins have been melted. I think they're okay, but it's hard to see. I am not too keen on buying a new motherboard, since a new dual-CPU motherboard will set me back $200, but I won't be heartbroken if I have to buy a new 1-CPU motherboard--easier to cool and silence!

Shuriken · Post by **Shuriken** » Mon May 05, 2003 1:37 am

Let me guess it is a Tiger MP?

It is a very common issue with this Mainboard. I am not sure if Tyan offers any warranty on this. I would ask if i were you. They have very good tech support. Maybe they are willing to do the repairs.

dukla2000 · Post by **dukla2000** » Mon May 05, 2003 1:54 am

SometimesWarrior wrote:Perhaps it was a bad idea to run so many fans off the board?

The fans should be irrelevant, cause they are running off the 12V line (after it is routed round the mobo).

If you cant get any help/warranty from Tyan, then it does bring to mind a hack I saw some time ago, where the guy found the onboard mosfets that were doing the CPU regulation, found the +5V 'start of the chain' and soldered an additional 16AWG cable from there back to the PSU +5V island (or of course you could borrow 1 from an unused molex).

But step 1 is you need to see what state the mobo ATX connector is in after you separate/cut/pull (throw a bucket of water on

) the existing melted mess.

powergyoza · Post by **powergyoza** » Mon May 05, 2003 11:42 am

SometimesWarrior wrote:According to powergyoza's current-draw measurements for his identical motherboard, I am indeed draining a lot of power from the +5V lines, almost 30A.

Or even more. What kinda video card do you have?

I'm just waiting for something similar to happen to my Tyan Tiger MP. <knock on wood> Thank goodness my connectors are still fine.

SometimesWarrior · Post by **SometimesWarrior** » Mon May 05, 2003 3:16 pm

powergyoza wrote:What kinda video card do you have?

Geforce3 Ti200. I looked for power consumption specs, but couldn't find any. My best guess is that it consumes 15-25W, since I thought I saw someone say the original GF3 was 20-30W. That would add a few more amps to the +5V and put me at >30A for +5V, I guess.

Shuriken wrote:Let me guess it is a Tiger MP?

It is a very common issue with this Mainboard. I am not sure if Tyan offers any warranty on this. I would ask if i were you. They have very good tech support. Maybe they are willing to do the repairs.

Indeed it is a Tiger MP. I checked Tyan's website and thankfully they carry a 3-year warranty (I thought it might only be 1-year). I'll call their offices tomorrow and see what they have to say. Can you recommend a good forum/newsgroup/bulletin board where I can read about similar incidents?

dukla2000 wrote:But step 1 is you need to see what state the mobo ATX connector is in after you separate/cut/pull (throw a bucket of water on ) the existing melted mess.

Yeah, I don't have any sharp knives handy, so I'm mashing the connector with a dull kitchen knife in the meantime. The smell of charred whatever-it-is is still nauseating.

I hacked through the connector where the biggest scorch-mark is present, and peering through at the motherboard-connector side, things look pretty hopeless; everything's black and burnt, and the pin looks to be gobbed up with plastic. Rather than possibly voiding my motherboard warranty by desoldering the connector, I'll try talking with Tyan first to see if they'll ship me a replacement.

Thanks for everyone's help on the matter!

Shuriken · Post by **Shuriken** » Tue May 06, 2003 12:48 pm

I recommend checking the www.2CPU.com forum.

Just do a search there.

For instance this thread: http://forums.2cpu.com/showthread.php?s ... +connector

But i am sure there are a lot more.

SometimesWarrior · Post by **SometimesWarrior** » Tue May 06, 2003 5:40 pm

Shuriken, thanks a lot for the links. Very informative! I'm glad I understand now what's going on. I've sent an email to Tyan, but from what I've heard at the MBM5 forums, they can be very slow to respond to email, so I will try calling tomorrow morning as well.

Powergyoza, do you think you will be doing a re-work on your board in the future, to prevent the possibility of suffering the same fate? If Tyan replaces/repairs my board, I'm sure I will make a Molex mod.

jojo4u · Post by **jojo4u** » Wed May 07, 2003 10:58 am

2 of my friends desoldered and resoldered the ATX-connector. The mobos where fine afterwards.

powergyoza · Post by **powergyoza** » Wed May 07, 2003 11:41 am

SometimesWarrior wrote:Powergyoza, do you think you will be doing a re-work on your board in the future, to prevent the possibility of suffering the same fate? If Tyan replaces/repairs my board, I'm sure I will make a Molex mod.

SW, I probably will not be modding my board anytime soon. I know I'll get trash for saying this, but I'm relying on good karma and luck to see me through. Besides, I'm too chicken to solder a connector to a mobo.

SometimesWarrior · Post by **SometimesWarrior** » Wed May 07, 2003 2:58 pm

jojo4u, thanks for the encouragement. I might still desolder the motherboard connector if I have to.

Anyway, I finally managed to hack the PSU connector off and scrape away the remaining charred plastic, and I only lost two motherboard pins in the process! (a +5V and a ground). And, since I'm also relying on good karma

, I'm gonna pop open my new PSU to do some seat-of-the-pants soldering of additional +5V wires. If I'm still alive afterwards, I'll tell everyone how it went.

I called Tyan about getting an RMA, but they said they'd keep the board for a week before sending it back, and I don't feel like waiting another 2 weeks for a working computer.

larrymoencurly · Post by **larrymoencurly** » Thu May 08, 2003 1:30 pm

will I need to be very careful not to overheat/burn anything on the motherboard?

I found that one sure way to overheat the mobo is by not heating up the solder enough, ironically, and 40W is probably the minimum needed for copper desoldering braid to work well. It may also pay to melt through the socket to slice it up so that the pins can be removed individually.

SometimesWarrior · Post by **SometimesWarrior** » Thu May 08, 2003 11:58 pm

Okay, I chickened out. While waiting for the soldering iron to heat up, I read some more 2CPU.com posts on the issue, and someone mentioned that any board-soldering I do will be really obvious if I send the board in to Tyan at a later date. I was aware of this fact, but when I heard someone else say it, it carried more weight.

If the motherboard is fried, and it might very well be, then my soldering trick won't help; it will just mean Tyan will no longer repair/replace it.

Thanks for everyone's help on the matter.

SometimesWarrior · Post by **SometimesWarrior** » Fri May 09, 2003 12:06 am

While waiting for the new motherboard, I started working on the newly-replaced PSU that Antec sent me. Unfortunately, I sent them a 1-fan model with sizeable heatsinks, and they sent me back a 2-fan model with dinky heatsinks and a restrictive front-grille. So much for my PSU duct! Also, even with the hairdryer trick, I still tore the warranty sticker; they creased it so tight that simply unfolding it ripped it in half.

DanceMan · Post by **DanceMan** » Tue May 13, 2003 7:55 pm

I had an MSI K7T Pro Ver.1 that I upgraded to a Duron Morgan 1.2G before MSI decided that wasn't a good idea. After 3 mos. the board and cpu died. The psu connector was welded to the motherboard. I was eventually able to get it off after soaking the connector in WD-40, and after a period to penetrate, used pliers to apply enough force to separate the plug. All the 5V pins were burned. I think the voltage regulator chip on that version of the board was weak.[/i]