PMG4 and Radeon problem

[SergioDeNice]

Hi,

Since yesterady my PMG4 Gigabit ethernet has problems starting up. It is equipped with an AGP Radeon 7500 and a PCI Rage 128.
If I connect on monitor to the radeon (ADC or VGA), it freezes on a blue screen
If I connect one screen to the Rage 128 (VGA), it boots OK but very slowly
If I replace the Radeon 7500 with an AGP Rage 128, startup is very fast, even with two monitors (via ADC on AGP and VGA on PCI).
It sounds like a hardware ou driver related problem with the Radeon.
What do you suggest I could try to investigate further?
TIA

Serge

 

[Raging Dufus]

Well, you've eliminated your GigE's AGP slot as a problem, since it works with the AGP Rage 128. Assuming you're using the same cable(s) connected to the same display(s), neither of those is likely to be the problem. If not, try swapping cables and/or displays to see if it's something there.

But if everything you've tried has been the same except for the graphics card, it sounds like your Radeon 7500 is fried. The only way to know for sure is to stick it into another known good AGP Power Mac, if you have another, and see if it works. If not, it's the card.

There's one last thing you could try, and that's to clean the contacts in the AGP slot and on your card. Even though the Rage 128 worked fine in the AGP slot, it may just be down to differences in contact. Blow the dust out of the slot, clean the contacts inside the slot as best you can, and give the contacts on your 7500 a good cleaning. Make sure it's seated properly, and give it another try. If that doesn't do it, your 7500 is probably done. Good luck!

 

[weckart]

Freezing on a blue screen is a sign of dying card. Try booting up with extensions off. You might actually get it to boot all the way up with no acceleration but even if that works, it's time to get a new card.

 

[SergioDeNice]

I forgot to mention but yes, disabling extensions did the trick. Today I cleaned the Radeon's contacts with isopropyl alcohol, put it back in and it worked, but for how long?
Do you think it would make sense to have it recapped?
On the other hand, I was suspicious about the PSU. The PM has a 1.3GHz CPU card, two video cards, SATA and USB cards in the expansion bay. Could it be too much power-wise?

 

[Raging Dufus]

On the other hand, I was suspicious about the PSU. The PM has a 1.3GHz CPU card, two video cards, SATA and USB cards in the expansion bay. Could it be too much power-wise?

Doubt it. Your GigE came with a PSU sufficient to power all that plus dual CPUs and an ADC display. They're not known to be particularly failure-prone. The Radeon 7500 isn't a particularly power-hungry card either. And if it was a power problem, I expect the first place that would show up would be problems with your USB peripherals and perhaps your SATA disks, likely causing kernel panics. If none of that is going on, I think you've narrowed it down to the graphics card.

 

[SergioDeNice]

What about recapping it then? I really love the triple screen setup...

 

[Raging Dufus]

What about recapping it then? I really love the triple screen setup...

Well, it couldn't hurt. Then again, it could be a complete waste of time, and it's not like recapping is a trivial process. If you have the skills and equipment, go for it... if not (or if that doesn't solve the problem), there are other and better cards out there that will allow you to have all of that 3-screen goodness. Do some shopping.

 

[weckart]

I forgot to mention but yes, disabling extensions did the trick. Today I cleaned the Radeon's contacts with isopropyl alcohol, put it back in and it worked, but for how long?
Do you think it would make sense to have it recapped?
On the other hand, I was suspicious about the PSU. The PM has a 1.3GHz CPU card, two video cards, SATA and USB cards in the expansion bay. Could it be too much power-wise?

The problem is that you would have to diagnose that caps were the issue. I suspect that since it booted up with extensions off that the problem is more to do with the actual processor die and the solder connections to the substrate. Repeated heating and cooling cycles can damage some of the solder connections within so that as soon as the the card gets even slightly warm as they do during the boot process they part along the cracks that had formed and you no longer have a usable card. I had a 12" PowerBook G4 1.5GHz with exactly those symptoms. Booting up with extensions off only activated the part of the GPU that seemingly didn't overheat in the past and it could hold a framebuffer image. Trying to boot normally ended in a bluescreen - sometimes with a cursor that vanished shortly after or wouldn't move but that was it. There was no way to fix that without replacing the GPU - which meant a new logic board.

If any caps on the board are obviously spent, then you could try replacing them. I think others on this board would be better placed to advise you whether it is worth the time and trouble trying that route.

 

[SergioDeNice]

Thanks for the advice!