MDD FW400 and DP 1.42 Ghz from FW800

V.Yakob

Tinkerer
Sep 6, 2023
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Not so long ago, I received a 1.42 Ghz dual-processor daughtercard from FW800, which I immediately installed in the FW400.
At the beginning, I didn't notice any problems, but later I began to notice oddities that had never happened before:

The machine can freeze tightly at any time: installing the OS, booting the OS, on the desktop... This happens with both OS 9 and OS X.
Sometimes the OS X boot comes out Kernel Panic
panic(cpu 0 caller 0x002E1EC4): Unable to find driver for this platform: "PowerMac3,6"
Latest stack backtrace for cpu 0:

Backtrace:
0x000954F8 0x00095A10 0x00026898 0×002E1EC4 0x002C12A0 0x002C1068 0x002C1AD0
0x000A9714
Proceeding back via exception chain:Exception state (sv=0x01555500)
PC-0x00000000: MSR-0x0000D030: DAR=0x00000000; DSISR=0×00000000: LR=0x00000000:

Kernel version:
Darwin Kernel Version 8.11.0: Wed Oct 10 18:26:00 PDT 2007; root:xnu-792.24.17-1/RELEASE
No debugger configured - dumping debug information
MSR=00001030
Latest stack backtrace for cpu 0:

Backtrace:
0x000954F8 0x000958F8 0x00026898 0x002E1EC4 0x002C12A0 0x002C1068 0x002C1AD0
0x00049714
Proceeding back via exception chain:
Exception state (sv=0x01555500)
РС-0x00000000: MSR-0x00000030: DAR=0x00000000: DSISR=0×00000000; LR=0x00000000: R

Kernel version:
Darwin Kernel Version 8.11.0: Wed Oct 10 18:26:00 PDT 2007: root:xnu-792.24.17-1/RELEASE
panic: We are hanging here...

Ignore the time, the screen photo was taken in October. The battery is fine.
I also thought that the problem could be in RAM, but I tried probably ~10 different memory sticks and had no positive result. These were different sticks, 256/512 MB, PC-2700/3200.

At the same time, sometimes it starts normally and can work for 30-40 minutes without problems, then it can freeze.
I ran processor performance tests in Geekbanch, and it worked perfectly, I can't say that there are any problems with the processor.

I have another motherboard from FW400, and I'll try to replace it, but with 1.25 Ghz I've never seen such problems.

He has thoughts, why is this happening?
 

S. Pupp

New Tinkerer
Apr 2, 2023
60
21
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Some years back, I replaced the dual 1.25MHz cpu that came with my MDD G4 FW400 with a dual 1.42MHz. I had no problems for years.

Over the past few years, however, both my long-serving G4 and the backup MDD G4 I obtained in 2018 have become unstable. I’ve had PSU’s refurbished, changed logic boards, changed CPU’s back to 1.25GHz (both single and dual), changed hard drives, RAM, PCI cards, AGP card, and even recapped a logic board, with no improvement in stability. It has been exasperating.

I wonder if there is a non-capacitor component on the logic boards that is wearing out, like the optocoupler in a Mac Classic tends to.
 

ClassicHasClass

Tinkerer
Aug 30, 2022
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www.floodgap.com
Interesting. I haven't observed any such issue with my own MDD, though I've been its only owner (I bought it new) and it has a Sonnet dual 1.8GHz CPU board in it now (it was originally a dual 1.25).
 

V.Yakob

Tinkerer
Sep 6, 2023
63
26
18
@ClassicHasClass, Yes, it's interesting. 😅

Today I replaced the motherboard, and got the same OS frosts and sometimes Kernel Panic.
When it freezes, the processor heatsink gets very hot.
And yes, every time the envious could be ~almost~ guaranteed to reproduce -- if you open a browser and try to open any sites, it could hang.
Maybe this processor is not working, it causes such oddities. I don't know.

Now I've returned the 1.25 processor daughtercard, and I'll leave this machine on again, let's see if it freezes.
 

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ClassicHasClass

Tinkerer
Aug 30, 2022
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www.floodgap.com
The processor could be getting hot simply because it ends up in an infinite loop or some such. For example, when my Quad G5 machinechecks, it just goes into a loop and the fans run at max. It may well be the CPU board at fault, but the CPU card heating up wouldn't be definite evidence.
 

V.Yakob

Tinkerer
Sep 6, 2023
63
26
18
After long tests, replacement of RAM sticks, reinstallation of the OS, and other attempts to do something, I start to think that this processor is faulty.

The system begins to behave strangely immediately after installing this processor. Previously, working memory sticks suddenly do not work, the machine may lose the disk and see it only after de-energizing. After rebooting, initialization may not be performed.

Any attempt to start OS X in most cases is unsuccessful, I see kernel panic or just howls on the screen, the cooler starts spinning at maximum speed. Sometimes it seemed to me that this MDD could turn into a quadcopter. If you're lucky and OS X starts, it's guaranteed to freeze in a few minutes.

OS9 works better, starts more often, but in general it also hangs at random intervals. Can work for 10 hours, or can freeze 2 minutes after booting.

It's a shame. I've been looking for this processor for a long time, and I was hoping to improve this computer, eh... :(
 

V.Yakob

Tinkerer
Sep 6, 2023
63
26
18
Hmm, can these hang-up problems be related to power problems?
Theoretically, the 1.42 processor requires more V to work.
If we assume that somewhere there are dried capacitors that cannot supply the processor with enough power?