Only a true Powerbook Genius Could Answer this One

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Only a true Powerbook Genius Could Answer this One

I have a PB Onyx 667. It is exhibiting some very strange behavior. First off, it doesn't startup. It chimes just fine, but that's it, no screen boot - it just sits, doesn't turn off, but sits. Furthermore, if I force restart, which it will do, it does not respond to key commands, such as flashing the PRAM. I noticed the fan at the rear of the case is not spinning up. Another symptoms is that about 1 in 20ish startups the it boots to the grey screen with the apple in the middle, and hangs there. The screen will flicker, and then go out. If I wiggle the screen (it has a broken hinge) the screen will flicker in and out. Thius would indicate a damage screen connection, but the plot thickens, the VGA out does not function either, but when the computer magically decides to boot to the grey apple screen, the external monitor works as well, indicating the problem is further upstream. Now here is the kicker: I decided to put the PB into the freezer for a few minutes on a whim. Sure enough it booted right up into the OS, and functioned perfectly for a minute or two until it regained room temperature. Thus I concluded it is some kind of heat problem. It is not actually overheating, but I think it believes it is (smart little guy). Does anyone know anything about the thermostatic mechanism? Any help would be greatly appreciated!!

Craig

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Does it really think it's overheating?

Perhaps it doesn't think it's overheating. If it's a bad connection somewhere, then freezing could cause it to contract and make contact. Same reason why freezing a harddrive will sometimes work (that and the drive head bit).

Just something to think about.

-BDub

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Re: Does it really think it's overheating?

Perhaps it doesn't think it's overheating. If it's a bad connection somewhere, then freezing could cause it to contract and make contact. Same reason why freezing a harddrive will sometimes work (that and the drive head bit).

Just something to think about.

-BDub


That's exactly what I'm thinking. My guess is that there are some traces on the motherbard that, when the board contracts from the cold, make contact so the board works properly. As the board warms up, the traces disconnect. You said the TiBook has a bad screen hinge; is there any other battle damage? Was it ever dropped? I highly doubt that this sort of problem would happen out of the blue.

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Simply use PB in freezer - problem solved!

Or not. :coolmac:

Have you reset the Power Manager? Zapped the PRAM (if possible?) If you press the caps-lock key, does the LED light up?

I 'spect Bdub and Doc W. have nailed it on the head. I hate to say it, but based on what you've written so far, your MLB is toast.

dan k

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Anybody know where to pick up a MLB on the cheap??

Thanks for the help!! The expansion idea is a good one. I think it definitely suffered a drop. I aquired it from someone rather brutal to computers. I haven't stripped it down yet to look for anything out of the ordinary, but it seems from your comments, it is unlikely I will. Another thought I had was that a failing component, i.e. resistor etc., may not be functional at higher temperatures. It being christmas perhaps I'll send the machine up north, see if anybody wants to do some outdoor computing. Does anybody know a good source for logic boards? Most scrappers are selling them ~ 400.

Thanks,

Craig

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Naaa, the screen freezes too

Naaa, the screen freezes too fast for any good outdoor computing up here!! Wink You could try e-bay.

m_d
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same problem maybe? help!

i have a powerbook g4 500mhz, this morning i turned it on and got this weird grey screen with multicolored vertival lines, no chime, no apple screen, no moving circle indicating that its booting up, even tho i can hear it working. it just freezes on this grey screen with lines.
i have a bad hinge thats broken on one side, so im thinking its just that what has damaged the video wiring as i opened it? pls help! i have no clue whats going on.

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You just diagnosed your own p

You just diagnosed your own problem; the video cable is punctured.

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Broken hinge issue

So last in the last day or two I noticed my powerbook screen a little loose, and then last night the left hinge broke and I can't shut the powerbook. I have not dropped it or abused it.

I found a hinge for $70-100 dollars. It says the repair is very difficult. Should I pay apple $350 ($700 if they say it was my fault) to fix it? Where else might I go?

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