Where do i start first...

[Charlieb000]

i came to this site because i discovered a bad cap in a PSU.

the PSU was a replacement for a low wattage PSU and was almost new though i had it for a while. i put it in the machine and it worked properly for a period of time (week or so). afterwards the board started randomly rebooting (reboots slow down over time, not stop though) and now it turns on in reboot mode, as though i hold the reset. using the post card cant rember the code, it appeared to be a faulty CPU, then later the powersupply cooked a 11ohm quarter watt resistor. (No, changing back to the other PSU did not solve problem)

havnt verified the psu cap (the suspect cap looks innocent,others have a bulge, no leaks or cracks). your site got my attention after seeing what happens to motherboards when there is a bad cap.
if its not a cap problem i dont want to be wasting my time, so what part of the board should i focus on first? the FAQ pages should have this information!!

board is l4s5mg/651+ branded "ACER"
now when i check im getting different codes at each start.
codes 80, 8c, 0F, EF, E3, 00, 6F, 80 agin, 08, 63, A8, Ed, 04,8F,63,0C,61,41.......

over 31 caps.

Charlie.

[PCBONEZ]

Re: Where do i start first...

First stop starting the thing with a bad PSU.
Your motherboard might survive that way.

Then get a good PSU. [Old one sounds too crappy to mess with.]

Then post some pics of motherboard and caps.
- Or list them all as so.
Make, Series, uF, Volts, Diameter
.

[PCBONEZ]

Re: Where do i start first...

Is this your board?
http://www.motherboard.cz/mb/ecs/L4S5MG651.htm
If so it's a re-branded ECS board.

[Charlieb000]

Re: Where do i start first...

Is this your board?
http://www.motherboard.cz/mb/ecs/L4S5MG651.htm
If so it's a re-branded ECS board.

i wanted to put the larger wattage psu in there because of a bad experience with an inadequate PSU, changing back did not fix it.

caps are from apparently two brands. none show degradation

wasnt expecting to be grilled on this...
its sort of like that with the cap arrangement..
that is probably an early version of the board. "V5.0A" some of the regulators/fets are moved, mine has a 12V for the CPU......
referring to the image,

there are five near the cpu where image has four,
purple OST:4700uf, 6.3v, 11mmor so
there are four more of the above, left the plastic frame (where there are two).

where the group of three is further left there is two:
green, G-Luxon 2200u 25v, 13mm

there are short stumpy ones, scattered on board 12 or so.
black OST 6.3v, 1000uf 8mm

thinner, scattered 8 or so
black Luxon, 25v 100u i think, 6mm

smaller about 3.
black luxion 22uf? 25v?, 5mm

smallest caps about 5
black g-luxon 10uf 25v, 4mm

[PCBONEZ]

Re: Where do i start first...

You aren't being grilled. I asked pertinent questions.
I asked for the minimum information needed to help you pull off a good repair.
I'm trying to get you helped in the least number of posts.
I also want you to -understand- what is going on....
If answering basic questions is a problem for you maybe you should throw the board away and go buy a new one.

It's an ECS board. I knew just from that it would have caps issues of some kind.

OST are -notorious- for failing with no bloating at all.
Very likely the biggest problem as you have no bloaters.

G-Luxon are high failure rate parts too but they -usually- bloat.
[Although no brand of cap -always- bloats when it's bad, just usually.]

Replacing everything 6mm diameter and larger [and/or] 220uF and larger is probably [and usually] enough, but not always.
Sometimes the smaller ones cause problems - but not very often.
If you do the standard repair and the board is quirky/unstable afterward then consider replacing the small caps too.

In choosing replacements:
Need to make sure the ESR is the same or less than the original.
Need to make sure the Ripple Current rating is the same or more than the original.
- Need series names to look up specs on the originals.
- You didn't give the series names as I asked.
- The series is marked on the can.
[G-Luxun [Luxon is same] -sometimes- doesn't mark the series. Any that aren't marked I need to see where they are to know what they do in order to make a good guess. - That's why I asked for photos. - Marking where a cap in question is on the photo in the link is enough if the layout is like yours and you don't have a camera. That's why I posted the link.]
.


Still need: Series name for 4700uF OST
[Are all the 4700uF electrically in parallel?]
[From your description these are the Vcore caps. 4700uF is a bastard [non-standard on mobo] size and it sounds like they used oversized cheap caps instead of properly sized good caps.]
[In Vcore uF is not as important as ESR and Ripple.]
[In Vcore on a P4 or C2D you want: at -least- 5000uF total for all the caps [that's the minimum, more is better]; ESR the same or lower than original; Ripple the same or more than original.
[Vcore is a good place to upgrade a lytic board to solid polymer but beware because some solid poly have worse ESR than some lytics.]

Still need: Series name or location for 2200uF G-Luxon
[Are all the 2200uF electrically in parallel?]
[From your description these are the VRM-high side caps. If so they are in parallel with each other and in parallel with the pins in the CPU power connector.]
[16v caps are the norm here. The fact they used 25v caps is another indication of oversized cheap caps.]
[Also a good place to upgrade a lytic board to solid polymer.]
[Based on factory poly boards the standard for P4 and C2D would be 4x330uF @16v -or- 3x470uF @16v. [In other words a tad over 1300uF total is enough.] A bit more uF there will somewhat 'harden' the system against slow power surges that get through the PSU. Less likely to crash when lights dim and come right back kind of surge.]

Still need: Series name for 1000uF OST.
[These are used for various POL [Point of Load] Voltage regulators scattered about the board and to keep noise out of long solder runs where the tiny resistance of the trace could allow a voltage drop [for ripple] from one end to the other.]
[Some of these will be in parallel with each other and some not.]
[NOT a good place to use polymers. These caps aren't all doing the same things and the outcome would be a complete unknown without doing a full circuit analysis for EACH cap. - That and polymers aren't likely to improve anything anyway for those cap positions.]

If you want to do the 100uF and below let me know.
.