Powermac Inscribed thus:

On Mar 24, 6:09Â*pm, Baron wrote:
Powermac wrote:
On Mar 24, 4:40Â*pm, Baron
wrote:
Powermac wrote:
Anybody here bother fixing computer motherboards these days? I
have seen a few that just need capacitors replaced, but what
about the ones where the power supply took out the board, are
they fixable?

I have an emachines motherboard (K8MC51G) that powers up when I
push the power button, but doesn't post of even beep an error
code. Seems to be a common problem, the PS it came with still
works (tested in another system), and there are no burn marks or
capacitors bulging/ leaking that I can see. Was wondering what
could be the problem (used different CPU's, RAM, and a new 550W
PS). Is there a common fix for that model?

Are those PCI/ISA post boards on ebay useful for figuring out MB
issues?

Yes its a common repair ! Â*Replacing bad caps often extends the
life of a machine. Â*Emachines... Yuk Â*Look for pin holes in the
bridge chip(s).

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Best Regards:
Baron.

Pin holes in the plastic chip housing? So you are saying a chip
blew up and in doing so poked a hole in the casing?

Yes ! Â*Quite common. Â*Sometimes you have to remove a heatsink to find
one. Â*I've seen the RAM PSU switcher chip simply vanish ! Â*Just the
bits of lead frame attached to the board.

Another interesting failure mode, is the CPU PSU switching chips
getting so hot that the solder holding them melts and they slide off
the pad and generally destroy things.

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Best Regards:
Baron.- Hide quoted text -

- Show quoted text -

Nothing on the board seems missing. I took the heatsinks off the
Geforce chip (odd there was no heat distribution grease or pad, it
must run cool) and it looks fine. I took the heatsinks off the chipset
chip (it had a heatsink heat transfer pad) and the chip looks like it
might have launched a piece off from the side (heatsink pad is missing
mateial in that direction that is in a lump on the edge of the
heatsink). So looks like the main chipset is blown (doesn't looked
cracked or overheated, but it would explain no error beeps on
startup). This board is junk, but I will test it with a PC post card
when I get it just for the heck of it.

Sometimes damage like that, if there is any, can be hard to spot !
There isn't always burn marks or discoloration to give you a clue.

The "Post Boards" are in my opinion a waste of money ! Most of the time
you couldn't repair the fault anyway, thats assuming that you actually
get a genuine fault result ! Those things are really aimed at problem
diagnosis on working boards where, for example, you have a missing
interrupt or bad address.

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Best Reagrds:
Baron.