Abit SR7-8X

[Toasty]

It was one of the projects I kept putting on the back burner for nearly a year...

Abit SR7-8X
P4 2.4GHz Skt 478 Northwood, not OC'd
512Mb DDR PC2700
NVIDIA GeForce4 MX400
80G Maxtor(2), CD/RW, Floppy
XP Pro
Purchased used off of Ebay 5 years ago.

On a quiet evening two weeks ago I was enjoying one of the STNG "Q" episodes when, it finally raised its ugly head with a loud report. ka-POW!!

Well, it WAS a quiet evening...

Preface
During a routine cleaning last year, I had noticed several small Teapo caps that had bulged, but the system was running fine. These were near the 3rd memory slot and between the Northbridge and the AGP slot. The caps near the CPU looked fine. The system(s) here get blown out every 3-4 months and I kept an eye on the caps in this one in case a bulger started in the VRM.

The system never had any boot issues, nor did it show any signs of a problem in any area, hardware or software.

My other concern was the Antec SL300 Smartpower PSU. I knew what I was in store for there. One of the recently acquired AcBel 550w units was going in there. But, I kept putting it off...

Part I
The system continued to run fine. Everything worked. Temps were where they always were. No odors or smoke. I shut the system down later that evening and started to look around. What cap had blown was not obvious. No vents. I expected to see some liquid or just 2 legs sticking out of the board.

I started it back up and it booted fine and went back to its normal operation... for about 2 hours. Then the whacko stuff started. Lost the video and the system hung. A power cycle yielded a message that the CPU had been changed. Reset to system defaults in setup and on it went. Got into Windows startup about half way and it BSOD'd with a message it couldn't find some DLL. Rebooted and it got to the desktop. Video bailed in 5 minutes. Okay, you win.

I shut it down and disconnected everything and took it into the shop. I started to pull the PSU out and realized the CPU cooler was in the way. Right. Knew it could not be that simple. Off came the cooler and out came the PSU. Opened it up and, yup, just what I knew I'd find. Fuhjyyu HELL! 4 domed ones and one that had vented. Probably that was the firecracker. The bastard sized 4700uF@10v, 10x36mm sucker. Into the pile with you!

Out came the AcBel and after a little razor saw work on the 8 pin plug to make it a 4 pin for this board, I put it all back together. There isn't enough clearance around the 4 pin connector on this board to use the 8 pin plug unmodified. The other systems I used these PSU's on had enough clearance. Also, the 24 pin plug fits over the 20 pin connector and leaves 4 pins sticking over on one end. No clearance problems though, so it went in unmodified.

I made a list of all the cap specs including the VRM and surrounding areas. Any cap with vent score marks was going to be replaced.

Powered it up and after another default reset in BIOS, it was back up. Got to the desktop and it was okay... for 15 minutes. It froze and killed the video. Permanently. Reboot after reboot, cold boot, PSU discharged, just the reset button, BIOS jumper reset, change the video card...
Nothing.
Nada.
Zilch.

-expletive deleted- -expletive deleted- -expletive deleted-

Okay. Fine! Research time...

(to be continued)

[Toasty]

Re: Abit SR7-8X

Part II

For various reasons, I ended up at Mouser. Digikey was too hit or miss with the sizes and brands I wanted. Either out of stock or didn't carry that cap in that size or voltage. Or, if they were out or non-stocked, the next capacity up was out or non-stocked too.

I've been itching to try the Nichicon HZ series, and here was the perfect opportunity. I'm also going to use them to recap the system I'm using, an Asus P4C800-E, but that's another epic yet to come.

Here's the list of the 24 original caps that I chose to replace:
(See attachment)

[Memory and AGP slot area] 
5 - 1000uF @ 6.3v - 8x12mm - Teapo SC (3 bulged)
4 - 1500uF @ 6.3v - 8x15mm - Teapo SC (all bulged)
4 - 220uF @ 16v - 6.3x12 - Lelon RGA - just because they were Lelon

[VRM area]
1 - 1800uF @ 6.3v - 10x16mm - Nichicon HM
6 - 3300uF @ 6.3v - 10x25mm - Nichicon HM
4 - 1200uF @ 16v - 10x25mm - Nichicon HD

The replacements:
[Memory and AGP slot area]
5 - 1200uF @ 6.3v - 8x15mm - Nichicon HZ (1000uF was out of stock)
4 - 1800uF @ 6.3v - 8x20mm - Nichicon HZ (1500uF was out of stock)
4 - 220uF @ 16v - 6.3x11mm - UCC KMG

[VRM area]
1 - 1800uF @ 6.3v - 10x16 - Nichicon HZ
6 - 3300uF @ 6.3v - 10x25mm - Nichicon HZ
4 - 1500uF @ 16v - 10x20mm - Nichicon HZ

I have a long-armed Pana-Vise circuit board holder and used it to secure the board and make manuevering it around easy.

Removal was fairly straight forward. Working quickly with a 800°F(425°C) and wide (4.6mm) tip on the soldering station made it go very fast. I could get across both solder points of the caps at the same time and they just about fell out of the board. I changed the tip to a 700°F(370°C) one but kept the width the same. Working quickly again with just the corners of the tip and the spring loaded type of solder sucker, I had the holes cleared promptly with no damage.

A quick cleanup top and bottom with some solder-wick and cotton swabs dipped in flux remover and I was ready to install the new caps. All I had to do was wait for them to arrive...

(to be continued)

[Toasty]

Re: Abit SR7-8X

Part III & Finale

Two days later, and Fedex dropped the box at my door. That was Ground, not Air. Nice.

I parsed out the caps I needed (I ordered extras of each one) and started inserting them one area at a time. I find it easier to install 4 or 5 in a group, solder them in, trim them, and move to the next area. Again, I chose to use the 800°F tip on the station, and used just the corners. I had some of the Chip-Quik paste flux (the type in the syringe) and found it very pleasant to deal with. The caps just flew into the board and each connection was done in a 1-2-3 quick count amount of time.

I cleaned up the board as before with the cotton swabs and flux remover. Using the ohmmeter, I verified that I had not shorted any of the connections to the surrounding ground plane.

Perfect! Time spent was less than 1 hour. Time to reassemble!

Back together in about 1/2 an hour. Cleaned up the CPU & heat sink, some fresh Arctic Silver and Done!

System booted up on first try. A quick BIOS setup to "Load Optimal Defaults", and XP came right up. The system has been running rock steady ever since. The CPU is idling about 10°F cooler than it ever has.

The "torture test" for this system has always been "Mavis Beacon Teaches Typing". It grabs a ton of resources and always made the CPU run very hot and the fan would ramp way up. I ran that for more than 2 hours. It was perfectly quiet and according to the log, the CPU only rose about 15°F.

Toast

[ratdude747]

Re: Abit SR7-8X

nice! good work.

[370forlife]

Re: Abit SR7-8X

Very detailed. Wish I was this organized when doing a recap.

[PCBONEZ]

Re: Abit SR7-8X

Have you ever heard the old sayings:

"The shoemaker's children always go without shoes."
or
"The shoemaker always forgets to mend his own shoes."

Yeah, I do it too.
.

[PCBONEZ]

Re: Abit SR7-8X

BTW:
Excellent report! - That's how it should be done.

[c_hegge]

Re: Abit SR7-8X

I know what you mean PCBONEZ. Our family computer has bad caps and I can't be bothered re-capping it at the moment.

Oh, and nice work fixing that board, Toasty.