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mike one · Mar 21, 2004, 10:13 AM

quick question.
i have two pismos. one 400, one 500.
i really want to swap the processors, is this an easy thing to do, do i need to worry about adding new thermal paste, or anything else like that?
i can't afford to screw up the one that is getting upgraded to 500. thanks in advance.

mic1.

cambro · Mar 21, 2004, 11:47 AM

You have to take the processor card out of the Pismo to replace the hard disk.

I've done this. It is easy. The heat sink is also easy to get on and off, though for the G3 it had, the heat sink probably didn't do all that much!

Anyway, you really have to seat that processor card VERY firmly. Otherwise, wierd things happen....

shr · Mar 21, 2004, 02:59 PM

Why exactly are you removing the processor card just to replace the hard disk? I have replaced the hard disk in my Pismo three times (from original 6 GB to 20 GB to 40 GB to 60 GB) and never had to remove the processor card.
I just lifted the hard disk cage up a little bit, carefully removed the four screws (be careful not to scratch the screen!) and unplugged the cable from the hard disk. Then I popped in the new drive and put all together again.
I only had to take out the processor when I upgraded my Pismo from 320 MB to 768 MB RAM by inserting a 512 MB SODIMM on the lower slot of the processor card (had a 256 MB SODIMM installed in the top slot by the dealer when I bought the machine). And guess how frightened I was at first as I had not pushed hard (you need to push really hard) enough to reseat the processor and the Pismo would not turn on

!

cambro · Mar 22, 2004, 08:05 AM

Originally posted by shr:
Why exactly are you removing the processor card just to replace the hard disk?

Hmm...I upgraded memory at the same time that I changed the HD so I think you are right! The lower RAM slot is definitely beneath the processor card....

Anyway, yes, you really do have to push down on that thing to get it seated. Really confused me when I didn't do that...happy chime, no screen...yuk.

legionare · Mar 22, 2004, 02:36 PM

IIRC, the machine's serial number is burned? on the CPU daughter card. So Apple System Profiler will now think one machine is the other. Could cause confusion if you have AppleCare on either of those machines and have to call Apple for repair.

mike one · Mar 22, 2004, 02:47 PM

sounds like a piece of cake.
just was worried about overheating, or having to thermal paste the heatsink.
i've swapped a drive in it b4, and top slot ram so i'm not too concerned about taking em apart.

bmhome1 · Mar 22, 2004, 05:30 PM

Do worry about overheating. The Pismo's processor face is joined to the heat pipe assembly with TIM (thermal interface material). Its a tiny black rectangle of wax that melts when heated up to efficiently move heat away from the chip. When the bond is broken, the wax pad will no longer mate perfectly and the processor will run hotter. How much hotter is a gamble. Apple's service manual states that the TIM must be replaced if displaced. Finding the same TIM pad is the problem.

When you swap processor cards either don't separate the heat pipe from the card (the correct way is to remove the two as a unit) or at the least try not to disturb the wax and press the two together VERY firmly and hope for the best. Pay close attention to how warm the Pismo runs afterwards. Anything over around 130-140�F indicates poor thermal transfer.

masugu · Mar 22, 2004, 10:38 PM

Maybe I am just a Moron...but when I was trying to replace a hard drive on my beloved Pismo, I fried the CPU.

All I got on boot up was a chime and a partial gray screen...

I ended up paying $400 or so to a mail order mac repair house to fix it. Probably not worth it, but for nostalgia sake...I use my Pismo now with OS 9 and Mozilla to surf the web from my couch...Have my Ti PB runnin a 20 " Cinema Display...

mike one · Mar 24, 2004, 08:03 AM

thx for all your help, surgery was a success! funny how the 500's heat sink is metal and the 400's is some wacky polymer.