Multilple Boards and Very HOT SOUTHBRIDGE S

[darylsutor]

Puzzling Hot Southbridge Phenominon...

I've got two a7n8x deluxe and 1 gigabyte GA-7vAXP board. All setup independently and all suffering from can't hold my finger on the southbridge without burning it. These boards did not used to be this way and are all socket A with rubicon capacitor. Newegg sought after boards and ran very well for many years. The capacitors look mint on all these boards. 1 board is dead and i'm assuming the other 2 will follow shortly. Installed heatsinks and still too hot to handle. All boards have the Nvidia MCP southbridge and when the ran properly, they give me very little reason to upgrade to todays technology.

Can anyone pinpoint a few a capacitors to replace for this type of problem. I can't see recapping whole boards full of seemingly great rubicons.

[370forlife]

Re: Multilple Boards and Very HOT SOUTHBRIDGE S

Power supply, check the 5vsb on it, it might be too high and is destroying them.

[darylsutor]

Re: Multilple Boards and Very HOT SOUTHBRIDGE S

Or most likely have I used my boards caps to and beyond the lifecycle of even a good rubycon CAP?

No sign of failure but if a cap is like a battery... It's time to replace my motherboard Caps?

[everell]

Re: Multilple Boards and Very HOT SOUTHBRIDGE S

If you are using the same power supply to test these mother boards, it may be a bad power supply. Read the brand name and model number of the power supply and tell us what you have.

The 5vsb rail feeds the southbridge chip. Try removing the main 20 pin power supply connector from the mother board. Then measure the voltage between the purple wire and any one of the black wires. Should measure 5 volts. If not ..............................

[darylsutor]

Re: Multilple Boards and Very HOT SOUTHBRIDGE S

So according to you, I would then be testing 3 different power supply's and a couple antec's. I may just do what you say. Of course I would have to strongly believe that not one of my power supplies are in spec.
My power supplies are...

Antec true power 2.0 480 watt
Antec Smart Power 350 watt model SL350
xconnect 600 watt

[370forlife]

Re: Multilple Boards and Very HOT SOUTHBRIDGE S

If they are the older antecs with the fujiyuu, I wouldn't be surprised.

[darylsutor]

Re: Multilple Boards and Very HOT SOUTHBRIDGE S

instead of adding another post i edditted and gave some model info... let me know if you need more and i'm getting ready to test these puppys thanks for the information on how to test the 5v rail i'll get back with my results but I may have to go fetch my meter at work....

[370forlife]

Re: Multilple Boards and Very HOT SOUTHBRIDGE S

ya the older smartpowers, truepowers, Neo's and so on had problems with the dreaded fuhjiyuu capacitors in them. The xconnect may also have a high 5vsb.

As everell said, you just put the positive lead of your dmm on the purple wire on the 20(+4) connector and the negative to any negative, it dosen't matter which negative as they all terminate in the same spot.

[darylsutor]

Re: Multilple Boards and Very HOT SOUTHBRIDGE S

OK Im excited and have to go get my good meter at work ill post back within 30 min...

[darylsutor]

Re: Multilple Boards and Very HOT SOUTHBRIDGE S

OK, I measured all and they vary from as low as 5.09 to 5.17 with the
xconnect 600 watt being the highest. I even measured a 4th powersupply that I have running to post here that falls inbetween. Is it possible that with a load on the P.S. these readings would change?

Otherwise, these readings are acceptable correct?

[kc8adu]

Re: Multilple Boards and Very HOT SOUTHBRIDGE S

i have seen many nvidia southbridges that ran to hot for my liking.stuck on a heatsink.
i would still open the antec's and look for the evil "F" word.
replace any you find.

[ratdude747]

Re: Multilple Boards and Very HOT SOUTHBRIDGE S

or find a delta/seasonic/( other brands; please post) to test with. although a recap would help too.

[darylsutor]

Re: Multilple Boards and Very HOT SOUTHBRIDGE S

On a side note, I opened another antec 350 watt power supply that i had on the shelf as labeled bad. What a mess that is inside. A cap leaking nightmare.

I was hoping someone could tell me if the blue esr tester or please list the one you have that is helpful for testing onboard capacitors. If i'm going to order caps, I want to check the seemingly good rubicons too and get my order done in one shot.

[KeriJane]

Re: Multilple Boards and Very HOT SOUTHBRIDGE S

On a side note, I opened another antec 350 watt power supply that i had on the shelf as labeled bad. What a mess that is inside. A cap leaking nightmare.

I was hoping someone could tell me if the blue esr tester or please list the one you have that is helpful for testing onboard capacitors. If i'm going to order caps, I want to check the seemingly good rubicons too and get my order done in one shot.

Hi Darlysutor

Why, yes the Blue ESR meter does well at testing onboard caps. The caps in the PSU are pretty straightforward (discharge them first!).

The Blue ESR meter (or any ESR meter) will test caps on the motherboard for ESR in place with one caveat: If there are multiple caps in parallel (such as the vCore caps very near the CPU socket) the ESR reading will be of all the related caps combined, and very likely an extremely low or even unmeasurable figure.

You cannot usually test the caps for Capacitance in place, but ESR is probably more important in this instance.

The "Low ESR" and "Ultra Low ESR" caps that you will find in the PSU and motherboard must be replaced with caps of a suitable ESR rating.
When you're ordering, it's a good practice to get some extras.

Good Luck,
Keri

PS. Practice on an old PSU first. PSU's are usually way easier to desolder/re-solder than multi-layer motherboards.