PowerBook G3 500 (Pismo) with 550 MHz G4 upgrade issue

[ried]

I recently acquired a Daystar Technology MACHSpeed G4 upgrade for my Pismo. It's a 550 MHz G4 installed on an original Pismo daughter card. It works intermittently, with a peculiar issue.

Sometimes, with the machine off, the CPU and its heatsink will become very hot and the machine won't power on. So I remove the batteries and unplug the power adapter, then let it cool off. If I remove the heat shield and apply light pressure to the daughter card (over the 300-pin connector?) in just the right way and press power, it'll boot. Take hands off of the daughter card, reinstall the heat shield, as well as the keyboard, and it'll run fine.

Attempting a reboot, however, often - but not always - makes the problem come back.

I have already swapped out the logic board. Same behavior on both, so I am led to believe this is an issue with the G4 daughter card. Any way to tell? Would that be repairable?

Thanks in advance.

 

[ried]

Well, may have found the issue. Top left corner of the 7410.



I put the original 500 MHz G3 back in the machine and it works fine. Is that 7410 replaceable? More comparison photos for reference.

 

[Byrd]

Seems these G4 upgrades were poorly transplanted (none are aftermarket, simply the Apple OEM 400/500Mhz part sent in for rework or a replacement). I’ve the same G4 CPU which boots with pressure applied - presume the BGA soldering wasn’t properly carried out. Yes, you can replace the CPU with same.

 

[Franklinstein]

I'd love to be able to do that sort of thing but a good rework station is well outside of my budget and I don't have one handy at work or anything, so lots of projects just sit. Maybe if enough pile up I can justify a few grand on a rework system, but it's not likely.

Anyway you may consider asking one of our resident BGA rework masters (hurd is probably your best bet) for some help. I'm sure you could get some assistance for a nominal fee. I'm considering doing the same (I have some old and/or broken ZIFs and PB CPU modules that I wouldn't mind having serviced if possible). It's getting the new CPUs that's the hard part. I looked on eBay and while 7410s are available, it seems they're only 400~500MHz parts, nothing faster (at least, nothing that's not installed to a board already). I wonder if Motorola/Freescale only produced the faster parts in quantity for Apple, or if perhaps they discontinued anything over 500MHz once the 7450 was released. I know IBM quit making the 970FX parts running faster than 2GHz once Apple quit using them, so maybe the same happened here.

 

[ried]

Thanks for the replies. I wonder if the 7410 that Daystar used is overclocked? It does say MPC7410 RX500LE on the part, though that might be unrelated to the clock speed.

@herd has masterfully repaired one daughter card that I somehow broke. We'll see if he can do anything with this one, too.

 

[jeffmr4]

The Daystar is overclocked. I think it was from 500 to 550.