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steve roche
01-01-2009, 01:13 PM
Hi-
I hope someone here has heard of this-- I have a Pismo which has started making a squealing noise whenever it is plugged into its charger.
The noise is coming from inside the laptop, and it stops when I unplug the
charger (an I-Go charger from Apple). It's similar to the squealing noise a photographer's flash makes when it is powering up, only louder. I play music over it so it doesn't drive me insane.

So far, I have:
replaced the sound card (also the A/C input card)
replaced the PMU-Battery board
replaced the Mother Board
checked for the noise in the speakers (it isn't)
checked for the noise in the screen or the screen inverter (it isn't)
It's not the fan
The HD is new, and silent
replaced the charger 3 times, this last one is by Apple
reset the PRAM
reset the PMU
pulled the battery, put it back in (no change)
replaced the CD/DVD combo drive


I did NOT:
replace the PMU battery (it's good)
replace the screen (it's good)
replace the inverter under the screen (should I?)
replace the battery (it's old, but it's good for an hour)
replace the processor (it is fully functional)


--It used to squeal constantly until the charge was at 100 percent, then it would stop.
(Lately it squeals all the time.)

--It's coming from under the keyboard, or maybe above or below the trackpad.

I used to worry that something was burning out, a capacitor or a diode,
but it's been three months, and it still works.. but it's driving me nuts.

What electronic component (diode, capacitor, etc) can make a high-pitched
constant squealing noise, for hours or days, or months at a time?
Something's going to burn up soon... what could it be?

(I only plug it in now when I am right there using it.. never when I'm away)

It's a nice computer, with a new HD, so i hate to trash it. Also, I can't afford to.


The only other hint I can give is that it all started when the original charger
began to get hot, smoke, and stopped charging. I mailed off for another one, a generic one from China, and that's when the noise started. So I ordered another one. Then I ordered an I-Go charger from Apple, but the noise continues.
The generic ones from China (actually two of them) have both tested ok.

Anyone heard of this? I've posted this in Mac Forums, Mac Rumors, etc,
but no solutions. What's left to replace?

thanks,
steve

Pismo G3
400mhz processor
712 mb ram
80 gig HD
Still a nice computer

M.Brane
01-01-2009, 04:22 PM
I bet it's the battery. If it only lasts an hour it's probably about toast anyway. mine lasts 3-3.5hrs.

steve roche
01-01-2009, 07:22 PM
No..

I take it out, and the noise remains.

I'm wondering if it's the processor, since the high pitch gets lower
when I do tasks like clicking on links or hitting 'return' or the spacer bar, etc.

thanks anyway-

sr

M.Brane
01-01-2009, 07:38 PM
I guess it could be something in that area with the heat pipe or possibly one of the thin metal shields. Mine is nearly dead-silent. Just some very soft noise from the hard drive unless I use the optical.

rwm
01-02-2009, 04:48 PM
I toss this out just because it has not been tried. No idea if it will do a thing but it won't hurt anything to try. Try another user account if you have one, if not create one and try it.