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bezoris
Member
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Posted: Thu Jun 15th, 2006 02:58 am |
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I have a Pismo with a 550mhz G4 Daystar card, 768gb ram, 40gb drive, os 10.3.9
No display whatsoever. No ghosting. Nothing. 
The green power light does not light up.
The Pismo bongs/starts/runs... in fact, if I wait (audibly) for the desktop to load I can click blindly and open folders, etc.
I first thought I had a bad inverter. Replaced that. No change.
Then I figured that the video circutry on the logic board had fried. Replaced the logic board. No change.
Powerbookmedic referred to this as a "common bong-no-display" problem, "esp w/ daystar upgrades." That was a new one to me. Any thoughts?
I've reached my diagnostic limits...
Thanks.
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Gary
Administrator
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Posted: Thu Jun 15th, 2006 08:53 pm |
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bezoris wrote:
I have a Pismo with a 550mhz G4 ...No display whatsoever. No ghosting. The green power light does not light up. The Pismo bongs/starts/runs... in fact, if I wait (audibly) for the desktop to load I can click blindly and open folders, etc.
How about external video. Is the external video working? If so, then you most likely have a bad cable (cut by a bad/cracked hinge), or your LCD has gone out.
If you don't have external video, then your video chip is fried, and you'll need to replace the logic board.
____________________
Gary Dailey
Daystar Technology
http://Daystar-Tech.com, http://Daystar-Store.com
email: gary@daystartechnology.com, chat: garydailey@mac.com
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bezoris
Member
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Posted: Fri Jun 16th, 2006 05:01 pm |
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Thanks for your response.
No external video (should have mentioned that in my initial post).
Are you suggesting that the onboard video is fried on the logic board? On both boards... including the newish replacement one? Or that the chip/daughtercard is fritzing?
Okay... but why would it otherwise boot up? Just curious...
Thanks,
- c
ps. Hinges seem fine. Cables, as far as I can tell, seem fine.
pps. So, has anyone heard about this "bong-no-video" thing. Does the phrase describe a specific diagnosable issue, or is it something of a catch-all for a group of problems?
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Gary
Administrator
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Posted: Fri Jun 16th, 2006 05:37 pm |
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bezoris wrote:
No external video (should have mentioned that in my initial post).
...Hinges seem fine. Cables, as far as I can tell, seem fine.
Okay, well. Then the most likely culprit is a video problem originating from the logic board. It could be something on the CPU card. But normally when the issue is something on the CPU card, you won't here it complete the boot. Like when the cache goes out on the Pismo, it will sometimes get bong no video, but stops right there. It sounds like you need a new video card.
You can also try of course, zapping PRAM (apple,option,p,r keys after the chime, and hold for three chimes). Or, try disconnecting all cables, removing the battery and hitting the reset button on the back to clear the PMU.
____________________
Gary Dailey
Daystar Technology
http://Daystar-Tech.com, http://Daystar-Store.com
email: gary@daystartechnology.com, chat: garydailey@mac.com
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bezoris
Member
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Posted: Sat Jun 17th, 2006 02:28 am |
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I agree (and my research seems to bear this out) that the onboard video on the logic board would seem to be the culprit here... except that I've already swapped boards 
I suppose both logic boards could have dead video chips, but doesn't that seem kind of unlikely?
Is there any other failure you can think of that might result in this type of scenario? Some bizarre sequence of dead cables...?
I have quite a few other systems, new and old - so it's not a question of lost productivity for me - but the Pismo is far and away my sentimental favorite. I'd hate to be unable to resolve this.
Thanks for your attention on this,
- christopher
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