About two years ago, I went dumpster diving and came back with two identical HP/Compaq D530 SFF desktops, of which one does not work (I also came home with an IBM Thinkcentre 8191KMQ from the same place, which works fine).
The first one has a good PSU and caps, when you power it up, it flashes the keyboard LEDs like normal, spins the fans but won't turn on the monitor or start its POST. This machine also knows when the RAM or CPU is removed by beeping and flashing a red LED, so it at least knows they are OK.
The second one had a fried PSU which also took out two Rubycon MCZ caps around the VRM (the caps around the CPU are a mixture of MCZ and Sanyo OS-CONs, and two two failed MCZs are right next to the 4-pin "P4" connector, which is really "P6"), but it still boots with the other PSU installed.
Sadly, the working board this is the "cheaper" of the two as such, as the board is populated with small Teapo SC caps whereas the non-working board is nearly all Rubycon with only two large 1500/6.3 Teapo SZ caps (ironically, on the cheaper, working board, these are Nichicon HM, but being that they're from 2003 they are of dubious quality, although they have not failed in this case). On the non-working board, it has Panasonic caps and purple SEPC (purple print) polys around the VRM and Rubycon YXGs around the PCI slots and elsewhere. The tiny caps are mostly G-Luxon and Teapo on both boards however.
I am using a known-good 512MB DDR400 stick, which runs at 333 on the working machine as it doesn't support 400, so it isn't a RAM issue. The CPU also works in the "good" system.
Additionally, I accidentally broke one of the delrin CPU fan spring mounts after swapping the CPU, so I had to cannibalize the other board to get the other one to run without overheating (the alternative being to shove my hand on the fan itself to force it down, which being that it's a centrifugal type, it doesn't involve the possibility of a fingers-versus-blades accident).
As the other board still boots without even a CMOS battery installed, I am stumped to why the other one won't boot.
The first one has a good PSU and caps, when you power it up, it flashes the keyboard LEDs like normal, spins the fans but won't turn on the monitor or start its POST. This machine also knows when the RAM or CPU is removed by beeping and flashing a red LED, so it at least knows they are OK.
The second one had a fried PSU which also took out two Rubycon MCZ caps around the VRM (the caps around the CPU are a mixture of MCZ and Sanyo OS-CONs, and two two failed MCZs are right next to the 4-pin "P4" connector, which is really "P6"), but it still boots with the other PSU installed.
Sadly, the working board this is the "cheaper" of the two as such, as the board is populated with small Teapo SC caps whereas the non-working board is nearly all Rubycon with only two large 1500/6.3 Teapo SZ caps (ironically, on the cheaper, working board, these are Nichicon HM, but being that they're from 2003 they are of dubious quality, although they have not failed in this case). On the non-working board, it has Panasonic caps and purple SEPC (purple print) polys around the VRM and Rubycon YXGs around the PCI slots and elsewhere. The tiny caps are mostly G-Luxon and Teapo on both boards however.
I am using a known-good 512MB DDR400 stick, which runs at 333 on the working machine as it doesn't support 400, so it isn't a RAM issue. The CPU also works in the "good" system.
Additionally, I accidentally broke one of the delrin CPU fan spring mounts after swapping the CPU, so I had to cannibalize the other board to get the other one to run without overheating (the alternative being to shove my hand on the fan itself to force it down, which being that it's a centrifugal type, it doesn't involve the possibility of a fingers-versus-blades accident).
As the other board still boots without even a CMOS battery installed, I am stumped to why the other one won't boot.
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