Imac G5 Isight woes.

[deckart]

Hello chaps,I'm stumped and need your help!.I have the above courtesy of Ebay,which had a shutdown and woul not reboot.It will power on,solid front light,fans spin up and HDD and Optical make the usual noises.
Diagnostic light 1 and 2 light up fine.The PSU had already been swapped out with known good and same scenario.
Caps on inspection all ok.Obviously didn't rely on that and pulled each one and tested with my ESR meter,all well within tolerance.So what the hell,I replaced all.
You gueesed it,same results.Done all usual checks,pulled pushed caps for bad joints,all fine,cables are good,no shorting on EMS side,so now I'm in head scratching mode.
I think it could be a bad IC or something,any advise how to find the faulty bugger would make my day and night.
deckart.

[Player2]

Re: Imac G5 Isight woes.

When it powers on, how long does it stay on? What do the fans sound like -> Do they run full blast the whole time it is on, or do they slow down after a second? Do you get any display on the screen?

I've never seen bad caps on the iSight G5s, but they do have a tendency for video problems, and the GPU is BGA (ball-grid array) so they are not very practical to repair if that is the problem. Go check Google to see how much a BGA rework station costs

[deckart]

Re: Imac G5 Isight woes.

Hi,power stays on,2 leds are lit,fans ramp up to max.

[Player2]

Re: Imac G5 Isight woes.

Hmm, sounds like it's probably the GPU problem. The third LED is the one that indicates successful communication with the LCD. Do you have a display dongle and an external monitor you can try? If it still doesn't work on an external monitor, I'd say you're out of luck.

I have seen some iSight G5s that overheat and just need the thermal compound replaced, but they will typically power on, ramp the fans up to 100%, and then turn off after about 5 seconds. If yours is staying on, I'd say that's probably not the issue.

[deckart]

Re: Imac G5 Isight woes.

Sorry to bump this but I still can't figure this out.History,user suffered spontaneous shut down(imac,not him!).Took to some Mac repair place,they tested PSU,which is fine,I've a few spare good ones and did the same just in case.LED 1 & 2 light up,fans start,white light comes on,and HDD?optical make the right noises,it then does the usual fan ramp up.
I replaced all caps,same result.Checked for cold shoulders,all ok.For the heck of it I took out a small filter cap,the flipping thing still powered up as above!.
If I connect a KB,it doesn't power it,but if I put a mouse in the same USB port the laser lights up.
I've looked at all components with a loupe and can't see anything remotely suspicious.
I need HELP!.
deckart.

[Player2]

Re: Imac G5 Isight woes.

Is the issue with the USB keyboard happening before or after you removed the small cap? First thing's first, put that guy back in!

Do you have an external monitor and the necessary display port adapter? See if you can get anything that way. The third diagnostic LED indicates that the connection to the LCD has been established, so let's try to get to the bottom of the video problem.

[deckart]

Re: Imac G5 Isight woes.

Arghhh!,USB issue happens irrespective of whether the cap is in or not.I have the panel discconnected at the moment,but have tried with it in,still same result.If the original user had a power spike,this could,maybe,have fried the CPU,be the first one I've encountered though.The thing is,with all peripherals discconected,it still does not chime,even with the little fella soldered back in.
I've resoldered dozens of these and know them quite intimately,LEDS diags,console warnings,ASD errors,but usually I can trace it back,not with this little bleeder!.