I know this isn't the greatest picture but this was the power supply from a Gateway 900G that wouldn't turn on. All the caps are Samxon GF series, I put a red dot on all the dead ones. I replaced ALL the caps with Panasonic FM and it's working great!
A lot of switching regulators datasheets mention that the capacitors should be at most about 1 cm away from the chips, to keep the trace lengths small.
So often, they can't do much about it, the capacitors simply have to be that close to the chips (whatever they are) that's mounted on heatsink.
I'd say the problem is the layout... they could have tried to move the chip a bit to the left so that the heatsink could have some fins extending horizontally and dissipate the heat better. Problem is there also has to be a bit of distance from the inverters as 700v-1400v can arc over if you're not careful.
But... it was cheaper for them to use a simple bent bar..the extrusion process for fins on heatsinks is a bit more expensive.
I created an account because it seems many people here have had the exact same problem I have. My Samsung SyncMaster 216BW computer monitor (5 years old) would flicker and hum, then shut down and had to be power cycled several times to stay on. I just ordered the replacements.
The caps in the worst condition are the CapXon 820uf 25v. The short 330uf 25v in the back of the first picture (out of focus) has slight leakage as well. My computer room probably gets well over 100 deg.F in the summer if my brother and I are both gaming in here. I wouldn't be surprised if that was part of the cause.
I've had two Samsung 226BW monitors with bad CapXons in their PSUs. Monitor PSUs do tend to run warm, since they don't have any fan or much ventilation to keep them cool, so bad caps should never be used there.
I love putting bad caps and flat batteries in fire and watching them explode!!
No wonder it doesn't work! You installed the jumper wires backwards
Main PC: Core i7 3770K 3.5GHz, Gigabyte GA-Z77M-D3H-MVP, 8GB Kingston HyperX DDR3 1600, 240GB Intel 335 Series SSD, 750GB WD HDD, Sony Optiarc DVD RW, Palit nVidia GTX660 Ti, CoolerMaster N200 Case, Delta DPS-600MB 600W PSU, Hauppauge TV Tuner, Windows 7 Home Premium
Office PC: HP ProLiant ML150 G3, 2x Xeon E5335 2GHz, 4GB DDR2 RAM, 120GB Intel 530 SSD, 2x 250GB HDD, 2x 450GB 15K SAS HDD in RAID 1, 1x 2TB HDD, nVidia 8400GS, Delta DPS-650BB 650W PSU, Windows 7 Pro
They're KZGs, a capacitor series from Chemicon. Their electrolyte is unstable (too much iron?) so they eventually fail in a few years of even moderate use, especially with added ripple and heat. KZJs also fail in a similar manner. All other series from Chemicon are good. Your images are interesting, though - KZGs often fail without bloating, but not so in your account of them.
Comment