Apple iMac 2006 mobo

[thewk]

I decided to post here because I think users of this forum are used to many kinds of boot problems, in this particular case I don't immediately suspect capacitor problem.

I have this iMac 2006 and when I press the power button hard disk and optical drive will spin up like normal, the two visible fans will make brief movement but not actually spin. If I plug USB keyboard to the back of the computer the backing light on the keyboard will blink quickly but not stay on. The machine will not chime or anything but it stays powered on until I shud it down by pressing the power button.

I have already sent this to an expert for reballing the ATI chip which now should be done, but above symptoms were present before the reballing process.

This repair guy now suggests that I send the mobo back to him and he would reball the Intel chipset as it could also be the real reason. What do you think, can the chipset be the problem, does it control the fans and does that USB -port thing indicate chipset problems?

[Toasty]

Re: Apple iMac 2006 mobo

Could be a power supply problem. Can you boot it with a CD?

>>I have already sent this to an expert for reballing the ATI chip <<

Why? What led you to do that?

Photos?

[ben7]

Re: Apple iMac 2006 mobo

If the flickering is at line frequency (60hz for US), then the big high voltage capacitor in the PSU is shot...

-Ben

[twbranch]

Re: Apple iMac 2006 mobo

I have had this problem too. I tried the PSU on mine to avail. Though it could be the PSU on yours the best way to find out is the LEDs on the back/bottom of screen. What do they show?

[BigTroll]

Re: Apple iMac 2006 mobo

seems in 2006 when they made the switch to intel logicboard failure was rampant, i know my 2006 core duo macbook would freeze if i moved it and eventually fail to boot, I had to replace the logic board, however before then i could put presure on it and it would boot, maybe its like the older ibooks where you could put in a copper shim above the chipset or gpu and see if it starts.