Re: Repairing Midplane on G5 iMac

On 2008-02-25 03:58:01 -0800, ric <publicmail@xxxxxxxxxxxxxxxx> said:

On 24 Feb, 19:48, Bream Rockmetteller
<bream(dot)rockmetteller(at)mac(dot)com> wrote:

Being an electrical engineer, I have no qualms about pulling the board
and replacing the capacitors. I assume that they are commonly available
electrolytics and shouldn't be hard to find. I also have the 45-page
document from Apple describing the board replacement process (from when
this was considered to be a fix-it-yourself machine).

Has anyone performed this procedure? Any hints or tips to pass along?

this is probably obvious, but i remember thinking "why on earth didn't
i think of that?" when I first heard it...

if you're replacing dodgy capacitors on a motherboard, don't mess
about trying to unsolder surface mount stuff. instead, grip the cap
firmly with pliers and pull it off vertically: you should end up with
the soldered legs remaining firmly attached to the motherboard, and
the cap itself lifting off cleanly. solder the new cap to the
existing legs. this is much easier than trying to solder to
motherboard traces and removes the risk of heat damage to the board.

you might want to practice this on some dead hardware the first time,
though!
ric

Thanks Ric! These are big electrolytic capacitors that are soldered through holes in the board, not surface mount. I plan to use the good old Solder Wick to remove them. Sad to think about how many hours of experience I've got doing this sort of thing...

I've already run into a delay. There's a small board with what appears to be an oscillator attached to the mother board with two tiny Torx screws. A single black wire comes off of this board and enters a hole in the midplane frame, preventing me from lifting the mother board from the frame. I've got no Torx driver that small and none of my Allen wrenches are the right size, so it's off to Sears to buy a tool.


--
Bream Rockmetteler
Donaldson's Dog Joy
509-540-0301

.

Relevant Pages

  • Re: LCD TV Repair Question
    ... solder sucker, some solder, and some new capacitors from somewhere like ... It's a bit like replacing all ... because equipment is cheaper than ...
    (uk.tech.digital-tv)
  • HELP: Replacing Lelon 10v 3300uF capacitor in computer motherboard
    ... I'm an aspiring electrical engineer (going into first ... year university in the fall) and have a problem with an old motherboard ... They are Lelon 10v 3300uF capacitors. ... replacing the entire motherboard, but it is fitted with 1024mb of PC133 ...
    (sci.electronics.basics)
  • Re: Motherboard Capacitors
    ... It's not worth it. ... After replacing the capacitors, the motherboard may still ... They leaked at the top end instead of at the motherboard end. ... Anyone had any luck replacing them with the newer 105c units? ...
    (comp.sys.hp.hardware)
  • Re: Freeze-ups. Is power supply the only remaining possibility?
    ... I'd take a look at the condition of the capacitors on the motherboard. ... PCB underneath the capacitors, or if the tops of the caps are bad, ... in life, or a factor of 128 times longer. ...
    (alt.comp.hardware.pc-homebuilt)
  • Re: Asus A7N266-VM with two leeky capacitors.
    ... Not the worst news but I have two leaky capacitors on my old ... The caps are situated right next to the ... the solder around the leads of the capacitor without harming the pc ... Usually a solder sucker of some type is used to remove the molten ...
    (alt.comp.periphs.mainboard.asus)