Replacing primary capacitors in P5-545K8

[rogfanther]

Hello,

Got another guinea pig. Seems something liquid was dropped over this computer, motherboard was toast and with a sticky goo over it. ( no caps vented ) .

The power supply was also dead, and after opening it, I saw why. I´m curious about what could make they blow like that.

Also, if I decided to fix this for testing other things, or even to partially fix it just to see which parts are good to keep before I scrap the rest, could I just substitute those caps ( provided nothing more in the primary section is shorted ) with different, lower capacity ones ? Those are 820uF, and I just found 330uF or some suspicious 560uF in my junkbox. As it is just for learning, and testing the parts, I don´t mind if it will have a lower efficiency ...


Thanks for your ideas.

[370forlife]

Re: Replacing primary capacitors in P5-545K8

These are rebranded solytech power supplies. They are not that bad at all, just don't push it much past ~350W. Give it a recap and it will be fine. Though it looks like something got those primary caps very, very hot. I would try replacing them with just some cheap junk 330uf 200v caps or so to see if it will still power up.

[goodpsusearch]

Re: Replacing primary capacitors in P5-545K8

Wrong voltage setting?

[b700029]

Re: Replacing primary capacitors in P5-545K8

Since the sleeve of the left one is still intact and so is the plastic separator near the PCB edge I'm guessing the cap internally shorted and dissipated heat like a resistor, which then caused the other one to vent too.

[rogfanther]

Re: Replacing primary capacitors in P5-545K8

Don´t know about the wrong voltage. The machine was in a basement, and its owner was traveling. I suppose that the cleaning lady drop something over the desk or the machine, and later, when the guy tried to start the computer, things blew.

If people thinks some other values will work, just for testing, I will try them and turn on the psu from a good distance.

[Toasty]

Re: Replacing primary capacitors in P5-545K8

Wrong voltage setting?

Agree.

Although I would find it odd for the US, in Brazil they have 115v, 127v, and 220v for mains. One thing that would make them blow (and overheat like that) would be the PSU's switch set to 115v and the unit plugged into 220v.

http://en.wikipedia.org/wiki/Mains_e...ity_by_country

http://www.controlledpwr.com/help-in...l-voltages.php

Did the fuse blow in the PSU?
The ICL thermistor doesn't look blown from what I can see either.

.

[rogfanther]

Re: Replacing primary capacitors in P5-545K8

Mostly 127V ( live + neutral ) and 220V ( live_1 + live_2 ) nowadays, although it is a problem when people who live in the 220V areas ( just a bunch of cities ) do not have the habit of double checking the voltage settings of electronics , more so when they buy it from the ´net.

I was told that it worked, and was turned off and left for a few months while the owner was traveling, then when they tried to turn it on it didn´t function. I opened the machine, and it was in this state.

Will check the fuse / thermistor in the afternoon.

Thanks.

[rogfanther]

Re: Replacing primary capacitors in P5-545K8

Well, fuse open. The termistor near the fuse has a "bubble" in the heatshrink sleeve. Measures about 20 ohms.

Will change the caps and the fuse, and test for some more shorts around.

[Toasty]

Re: Replacing primary capacitors in P5-545K8

Check the main switcher(s). With a mains cap failure, you'll find that it blows at least one of them many times.