Hi GaryN and DieHard,
thanks for this incredible expertise on my problem. You are my heroes! I could barely follow DieHards calculation, but I am afraid he is right.
Yeah… math geeks…
I have changed the thermal paste one time when I have built-in my verax-fan-kit ... 20 years ago. But I am sure that the verax kit is doing a fantastic job and this shouldn't be the reason for a fried CPU.
OK. Know that you're one of the few lucky ones who actually have that fan kit. It's the only MDD-specific fan upgrade ever made that both more or less works
and is also quieter than the stock Pabst by far without sacrificing cooling for the sake of quietness.
But that's 20 years ago and since that I was afraid to "redo" the thermal paste again, because I have read so many article about damaging the G4s CPU-board in this process.
Phoo ! You did it once, and evidently did it properly and now you're a veteran. Why should the second time be any different? Piece 'o cake! Seriously, You can and should renew the paste after so many years on a vintage machine you depend on. Actually, you don't have a choice because one way or another, that board is coming out for service or replacement. Think of it like a lube and oil change on a car… you wouldn't skip that just because you're afraid of a little dirt only to have the engine seize on the highway… late at night… with your girl in the passenger seat…
The temperature always were around 40 degrees Celsius (because the machine was running with the verax kit and an opened MDD (really open for better cooling!!).
Wow… The Verax kit is the
only kit that does NOT cause a problem running the MDD open. It must be louder open than closed however (?)
So now I wonder: When did you first notice it is running at 917 MHz? Running at 3/4 speed will certainly keep it cooler that a fan upgrade… 40°C is freakishly low for an MDD. How do you know the temp, by the way? Is that in OSX? If it's with a temp probe pointed at the heat sink, that doesn't count. That doesn't measure the temp at or very near the CPUs.
Okay, what are my possibilites: I cannot renew any solder joints ... I could swap the board from my second "SOS"-G4 MDD 1Ghz. Mmh, but this one is running at the moment and I have just swap the harddisks to the newer (a little bit slower) G4 with only 1Ghz. I will see if this SOS-G4 is running with its 1GHz almost as fast as the 1.25GHz or I have to buy a new one somewhere. I was glad to have to 1Ghz waiting for that case, but there is no verax-kit in it. Maybe I get another with the verax-kit or a have to swap the verax-kit including the fans and PSU from the fried G4 to the slower one. But I am glad that I could (maybe) still use the verax-kit. Another G4 is findable - I hope.And if I find something I should renew the thermal paste for sure ...
Of course you can! According to DieHard's chart, there is only
one little SMD that has come loose and the chart even points right to the correct one:
R403By "come loose", I mean the solder on one end has developed a minuscule crack. A quick heating with a very small-tipped soldering iron will melt it back together in a few seconds. In fact, the resistance is negligible and unimportant. If you break it loose and lose it in the carpet, you can just bridge the contacts back together with a tiny bit of bare copper wire soldered down to the pads. If the worst happens and you drop the whole board on the floor then step on it in a panic,
then you can consider replacing it but until then, it's a simple fix.
Compare this with the other alternatives you describe… moving half the guts from one machine to another and hoping everything just starts up without a glitch afterward. The logical course is clear. If the worst somehow happens, I'm sure either DieHard, myself or one of the other intrepid souls around here can scrape up a working 2x1.25 for you. Go for it!
When you own a 1966 Mustang, you really need to not be afraid of using a socket wrench every now and then.