Dell Optiplex GX270 ghetto heatsink mod and recap

[momaka]

I got this board a year or so ago. Didn't really care for it since it had bad caps and I got the board with nothing else. Thus, I decided to do some experimenting on it....

First was a recap. I used pretty much whatever I could find. Probably broke every rule/convention there is on recapping motherboards. For example, the caps on CPU VRM-high were all 16V 1800uF Nichicon HNs (H03 datecodes), but I used 16V 1500uF Panasonic FLs that I pulled from various Xbox 360's. If that's not bad enough, you should see the CPU VRM-low - here I used a mix of used polys as well as used and new eletrolytics. Here's what replaced what:

Originally [CPU VRM-high]: 3x 16V 1800uF Nichicon HN (H03 datecodes) - all bulged
Replaced with: 3x used 16V 1500uF Panasonic FLs from Xbox 360s

Originally [CPU VRM-low]: 9x 6.3V 1800uF Nichicon HN (H03 datecodes) - all bulged
Replaced with: 1) 3x used 2.5V 820uF United Chemicon PSC (polymers) from Xbox 360s
Replaced with: 2) 2x used 6.3V 820uF Nichicon HN (custom 8mm dia by 25 mm height) from Xbox 360s
Replaced with: 3) 1x used 6.3V 560uF Elite?? ECP polymer from a random Asus motherboard
Replaced with: 4) 2x new 10V 1000uF Nichicon HM
Replaced with: 5) 1x new 6.3V 1800uF Nichicon HM

... yup, I totally disregarded that half-rule for polymers in the CPU VRM. But hey, the board actually worked fine. The fastest P4 CPU I have is a P4 2.66 GHz Northwood which isn't very power hungry (only 66W TDP), so those caps in the VRM-low should be more than enough. Heck, even this current configuration is probably much better than the VRMs I've seen on some older mid-range consumer boards. The total capacitance on the CPU VRM-low dropped from 16200uF to 8460uF after the recap. ESR and ripple-wise, the old Nichicon HNs were good for 1.5 mOhm and 17760mA when all in parallel. Contrast that to 1.11 mOhm ESR and 22240 mA ripple for the new caps.

Luckily, the only bad caps on this motherboard were the CPU VRM-high and CPU-VRM low caps, so a full recap was averted. The caps on the rest of the board are pretty much just Panasonic, except for 2 or 3 Nichicon HM's (with bad date codes as well). I might change those as well, but the board is working fine right now so I probably won't. Anyways, here's a pic of my handiwork:
https://www.badcaps.net/forum/attach...1&d=1334645782
Good think you can't see the underside. I had quite a bit of a struggle with just my 35W Radio Shack iron. In fact, if it wans't for the heatgun and the flux, I wouldn't have been able to do it.

After seeing that the board worked, I decided that when I have time some day, I will modify a case so that I can make this my daily-use computer. Of course given that I didn't have the original GX270 CPU heatsink and that the retention mechanisms from other P4 did not fit meant i had to come up with a way to hold a standard P4 heatsink in a non-standard GX270 retention mechanism.

After playing around with various hardware for a few hours, this is what I came up with:
https://www.badcaps.net/forum/attach...1&d=1334645782
https://www.badcaps.net/forum/attach...1&d=1334645782
https://www.badcaps.net/forum/attach...1&d=1334645782
Yup, it's totally , but it works just fine. Flipping and moving the board around doesn't make the heatsink move at all. The rubber band that holds the fan also happens to dampen the vibrations from it, so the fan is a lot more quiet.

Here's another close-up of how the heatsink is held in place:
pic 4
https://www.badcaps.net/forum/attach...1&d=1334645782

Basically, the hardest part about this mod was to think of what to use to hold down the heatsink. Having lots of random hardware laying around is very useful. I'm not sure what that metal spring piece came from, but it's what made this mod possible. It's balanced on that piece of wood so that it inserts a force at the center of the heatsink and it's held by thick steel wire down to the plastic heatsink retention/holder.

And here's all of the hardware (minus the plastic wind-deflector piece on the fan):
https://www.badcaps.net/forum/attach...1&d=1334645782

As you can see, very simple (unlike the initial plans I had). I can actually install/uninstall the heatsink faster than a regular heatsink.

All that's left to do now is figure out the front panel header (still can't find any info on that), decide which of my cases would be the easiest to modify, fix a PSU for use with that computer, and also find some cheap DDR RAM.