I recently bought a shitload of off-lease Dell SX270 systems, all of which had bad caps in them. These little critters are prone to even roasting good caps, I see them all the time with bad Rubycon's and Panasonics in them. The reason is poor heat dissipation. Even good caps will fail if they overheat.
I noticed in this bunch of SX270's, there was a lowly little SX260, which uses the same case, just a different motherboard. It was full of Nichicon HN series caps, that miraculously haven't failed, the system still worked... I was scratching my head wondering why as I recapped it anyway... When I went to test it, I noticed something... The fans in the SX260 blow in reverse of the SX270. The SX260 blows downward, pulling in cool air from the top, through the system, then through the CPU heatsink, and then out of the case through the bottom. The SX270 pulls air in from the bottom, and then passes the already hot air over the northbridge (which makes it even hotter), then over a 5W resistor (which gets miserably hot), and then expels out the top of the case. See the image below:
This made me wonder what drugs the Dell engineers were on when they thought of this... The caps around the resistor are always the first to go, and there's no wonder why... The fix I came up with is insanely simple. Just reverse the fans in the cage, so the cool air is drawn from the top, pulled across the motherboard and CPU, and then expelled from the bottom.
The process for this is extremely easy. Just remove the side of the case, and unsnap the fan cage from the heatsink bracket. Carefully push the rubber fasteners outward, releasing the fan from the bracket.
You now want to grab the rubber fasteners from the base, and give them a tug, they'll pop right out of the fan.
You then want to simply turn the fans around and reinstall the rubber fasteners on the opposite side of the fan, reassembling everything reverse of how you took it apart.
When done, this is how the air will flow though the case:
After doing this, the resistor and caps around it are MUCH cooler. The CPU isn't running any warmer either, and I've abused the test system I initially tried this on, no glitches whatsoever. Those wanting to squeeze a few more years out of their SX270 may want to give this a shot, as it's proven itself very effective on several of mine.
I noticed in this bunch of SX270's, there was a lowly little SX260, which uses the same case, just a different motherboard. It was full of Nichicon HN series caps, that miraculously haven't failed, the system still worked... I was scratching my head wondering why as I recapped it anyway... When I went to test it, I noticed something... The fans in the SX260 blow in reverse of the SX270. The SX260 blows downward, pulling in cool air from the top, through the system, then through the CPU heatsink, and then out of the case through the bottom. The SX270 pulls air in from the bottom, and then passes the already hot air over the northbridge (which makes it even hotter), then over a 5W resistor (which gets miserably hot), and then expels out the top of the case. See the image below:
This made me wonder what drugs the Dell engineers were on when they thought of this... The caps around the resistor are always the first to go, and there's no wonder why... The fix I came up with is insanely simple. Just reverse the fans in the cage, so the cool air is drawn from the top, pulled across the motherboard and CPU, and then expelled from the bottom.
The process for this is extremely easy. Just remove the side of the case, and unsnap the fan cage from the heatsink bracket. Carefully push the rubber fasteners outward, releasing the fan from the bracket.
You now want to grab the rubber fasteners from the base, and give them a tug, they'll pop right out of the fan.
You then want to simply turn the fans around and reinstall the rubber fasteners on the opposite side of the fan, reassembling everything reverse of how you took it apart.
When done, this is how the air will flow though the case:
After doing this, the resistor and caps around it are MUCH cooler. The CPU isn't running any warmer either, and I've abused the test system I initially tried this on, no glitches whatsoever. Those wanting to squeeze a few more years out of their SX270 may want to give this a shot, as it's proven itself very effective on several of mine.
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