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Author Topic: QS2002 1.0GHz DP CPU card repair?  (Read 4622 times)

reeskm

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QS2002 1.0GHz DP CPU card repair?
« on: January 05, 2018, 01:19:01 PM »

I just bought a used QS 2002 with the max-spec 1.0 GHz Dual Processor. I bought it not knowing if it would work for cheap.

It is not booting and looks like a bad PMU, but...

After troubleshooting for 2 days, I finally discovered that the CPU card is bad.
The power supply, logic board, PMU battery, RAM, and video have all been ruled out.

I have swapped the card into another QS2002 that I own and it fails to boot up, too. It's not the logic board or the PMU - putting a 800MHz single processor from the other machine into the dual machine works fantastic -- it passes Apple Hardware Test with flying colors.

Question is - is this CPU garbage or is it possible to fix it? It does not show any signs of overheating at all, but it had very little of the original thermal pad left on it when I took it apart. I don't know for sure, but it looks like someone tried removing it and re-seating the heat sink.

The only thing I could think of is to test the caps for open circuit or something.
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Ncc74656

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Re: QS2002 1.0GHz DP CPU card repair?
« Reply #1 on: December 11, 2023, 10:06:36 PM »

did you ever get it fixed? i have been looking for some DP cards to test out and maybe repair.
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alectrona6400

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Re: QS2002 1.0GHz DP CPU card repair?
« Reply #2 on: June 06, 2024, 04:49:07 PM »

Don't want to necro a thread but I thought I should share my experience with the dual 1GHz G4 cards... From my experience, and from what several other people have said on the internet, these are honestly some of the least reliable G4 CPU cards. From what I've heard the CPU or the L3 cache itself is usually an issue; my QuickSilver 2002 freezes up when it tries to start so probably L3 related. The CPUs were bleeding edge technology, the original Motorola PowerPC 7455 chips. The 7455A and 7455B are far more reliable in this regard because they're built to work with these higher clock speeds and fix issues present with the original 7455. If you look hard enough you can find some pictures of burnt out 7455 chips, particularly on MDDs for sure. I once had a dual 1.25GHz MDD I saved from recycling years ago and within a minute I noticed a bit of smoke coming from the heatsink/CPU area, and sure enough one of the processors finally gave out. In fact... the dual 1GHz and Single 933MHz QS cards were the only QS cards to use the 7455, all other cards still used the 7450. While failures are quite rare, some machines were used a lot back in the day and that wear could increase the chances of a dead CPU. A dead L3 could be related to the ceramic capacitors or the chips themselves, and no chime could be a dead CPU. If you were to have interest replacing those components you would need to either find someone who specializes in BGA rework, or learn how to do BGA rework.

In my opinion the most reliable G4s are easily the graphites. Those last forever.
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