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Making a G4 Pismo upgrade at home

LightBulbFun

LightBulbFun

macrumors 68030
Original poster
Nov 17, 2013
2,907
3,203
London UK
so where to start... well its well known that several CPU upgrade companies on some CPU upgrades would simply take the stock CPU Card or Motherboard and de solder the old CPU and solder down a new chip (and cache some times) so that got me thinking a while back hey maybe you can do that at home... well i finally bought the equipment to do so and over the past couple days I have been experimenting with it and today with a G3 Pismo card I successfully removed the old PowerPC 750 and soldered on a new 7410 Chip! im really happy about this the fact it actually worked only side thing is it looks like the L2 cache died during the swap (POST reports cache failure) now this is not a guide or anything just a quick post to let others know it can be done if you wanna read more about it, @Daniël Oosterhuis is also when he can planning to do something like this and he posted some of my pics on a couple Mac Facebook groups. also if you want to read more about it and see others that have done it check out this post here https://68kmla.org/forums/index.php?/topic/28556-imac-g3-rev-a-c-g4-cpu-upgrade/

maybe ill talk a bit more in depth about it later :p

and now for all the pictures :)

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That's neat! I've seen some of the reballing services on fleabay but I've never tried it.

Were the cache chips replaced also? I wonder if it could be a firmware, or bus multiple setting or something like that. There used to be powerlogix program that would let you set the cache speed as a multiple of the bus.
 
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I certainly couldn't do anything like this (although I do have the appropriate CPUs lying around). Good work.

Next step would be to solder a 1.6 or 1.8 GHz CPU into an iMac G4 20". Now that is a Mac I would love to have, although I imagine it'd run about as hot as my Cube with the G4 tower version 1.8 GHz Sonnet Encore in it.
 
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thanks guys :) (btw in the 68kMLA link someone just swapped a G4 Chip into an iBook Clamshell I find that super awesome esp as there where comercial Pismo G4 upgrades but no one had ever done an iBook :) )

@flyrod the cache thing is Just Bad luck. L2 cache is known to be a bit pokey on Pismos and i guess it copped it during the Chip swap. (the machine detects the cache but determines its bad and disables it) (on Pismo Upgrades I dont think they swapped the cache and one guy who sent his Pismo card off to a BGA re worker with his own G4 chip got it back with working Cache)

@redheeler theoretically you could do this to an iMac G4 and a faster chip but its a matter of finding the chip and wether or not it actually works (ie it would it need some sort of firmware patch) I know Daystar had an exchange program like this where you sent in your iMac G4 and they would swap and clock a new CPU in. tho when it comes to iMacs im much more interested in trying this on an iMac G3 :)

@iModFrenzy Leo runs, well the 16GB CF card helps but its not what id call super fast its relatively usable the lack of L2 cache does not help it tho
 
thanks @harrymatic :)

I am really chuffed with it I got it updated to 10.5.8 with no issues and its been rock solid stable machine goes to sleep and wakes up fine leopard :) I am really happy with it

the next machine id like to try this on (or see someone else try) is an iMac G3 slot loader/tray loader and run leopard on it. I have a Flower Power iMac that would work but those are rare and i dont want to ruin it if i balls it up (my FP iMac is the non US 500Mhz model so it has the normal 750 with backside cache that is compatible with a 7410 and has the Model identifier of PowerMac2,2 I have a video of this iMac on my youtube channel).

heres a pic of the Pismo running 10.5.8 Leopard :) it does not detect the battery properly when its in the left bay (but can still tell when i pull the power adapter and tells me its running on battery despite it saying no battery is available LOL. if i put the battery into the right bay its detected fine) (this is just a Leopard bug its not related to the CPU swap)
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LightBulbFun said:
thanks @harrymatic :)

I am really chuffed with it I got it updated to 10.5.8 with no issues and its been rock solid stable machine goes to sleep and wakes up fine leopard :) I am really happy with it

the next machine id like to try this on (or see someone else try) is an iMac G3 slot loader/tray loader and run leopard on it. I have a Flower Power iMac that would work but those are rare and i dont want to ruin it if i balls it up (my FP iMac is the non US 500Mhz model so it has the normal 750 with backside cache that is compatible with a 7410 and has the Model identifier of PowerMac2,2 I have a video of this iMac on my youtube channel).

heres a pic of the Pismo running 10.5.8 Leopard :) it does not detect the battery properly when its in the left bay (but can still tell when i pull the power adapter and tells me its running on battery despite it saying no battery is available LOL. if i put the battery into the right bay its detected fine) (this is just a Leopard bug its not related to the CPU swap)
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Click to expand...

I'm extremely impressed by what I'm reading & seeing here. Breathing new life into beloved PPC machines must be enthusiastically applauded, and I certainly admire your skills. I only wish my technical skills were up to it, but they never will be....... not until pigs can fly!
I have a spare Pismo which I'd love to be upgraded in such a fashion. Is there any chance of this? Would obviously reimburse for required parts & labour time etc.
I also have a pristine FlowerPower like yourself, so am also interested in whatever G4 upgrade you may eventually perfect on that 'bijou'.
 
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thanks for the complements :)

my main problem with doing this for someone else (especially if they want to pay me/exchange with me for the service) is if something goes wrong. if i mess up on my own machine i mess up my own machine no loss on anyone else. but say you send me your Pismo card or so and i go to upgrade it but something goes wrong then suddenly your without your Pismo. the main issues that could arise during the CPU swap is during lifting of the old chip a Pad on the PCB lifts off with the old chip. then if i get the chip lifted without any pads lifting then i have to clean up all the pads up of old solder and theres risk of pads lifting then as well. also theres a chance the board could "pop corn" moisture in the board expanding and ripping it apart internally basically.

iv currently tried this on 2 ZIFs and one Pismo the first ZIF pop corned while removing the old chip. the second ZIF i got the new chip on but so far i only get a chime but no video (but that might be related to other things, check out the link i posted in the first page for more details Page 3 and 4 is where i step in) and the Pismo was mostly a success apart from the loss of L2 cache. so out of 5 7410s I ordered i have 3 left and been deciding what to use them for if I could find a slot loading iMac thats not so rare something like a 400Mhz or 500Mhz 2,1 or 2,2 would work nicely for this :) so would a 333Mhz Tray loader. if someone wants to send me a machine for free with no strings attached for me to experiment on then im fine with that. my issue lies when someone wants something back in return as i cant guarantee success hope this makes sense (as several people have asked about me doing a service for them)
 
bit of a status update and some good news. so id like to report that the G4 upgraded Pismo has been working nicely since i did the CPU swap on it (never had it kernel panic for example) but the non working L2 cache was bugging me so yesterday i decided to fix it :) based on other reports of L2 cache failure on Pismos i decided to reflow the CPU again and a little bit of the surrounding circuits around the CPU and that seems to of done the trick its now fully reporting L2 cache and no POST failure messages :D here are some Pictures and geekbench results showing the improvement L2 cache makes

http://browser.primatelabs.com/geekbench2/2625052

http://browser.primatelabs.com/geekbench2/2625050




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That's great! So you think it was a bad connection under the CPU that the reflow fixed?

Any plans for trying above 400MHz? Your first photo shows the 7410 is rated for 500. :)
 
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indeed that is what im thinking (I guess one of the balls didn't drop so to speak :D ) in regards to speed im thinking of keeping at 400Mhz as an indication of the fact its been done at home/DIY as the Makers that offered Pismo CPU upgrades always did 500Mhz or 550Mhz ones never a 400Mhz one i guess i could try 600Mhz but im not sure about thermals... over one the 68kMLA the other guy doing this got an iBook G3 clamshell rocking a G4 too at 533Mhz (with a fan to make it stable). overall im very happy with it and the temptation to do my iMac G3 is even stronger (I have been keeping an eye out for a suitable iMac G3 but nothing reasonable has come up yet) I have 3 7410s left atm
 
well @flyrod asked about clock speeds so here ya go :)

I got the thing clocked up to 600Mhz! its quite fast at that speed especially with the 1MB L2, I did get it benchmarked in tiger. tho while doing so in Leopard the L2 cache died again mid benchmark and crashed OS X LOL and when i rebooted it had same symptoms as before so prolly a dodgy ball again, so ill give the CPU another reflow tommrow :) kinda glad it was the L2 and not the CPU it self as the L2 is a known issue not related to clock speed (the fan had not even kicked on at the point it panicked). this is still with the original stock L2 cache chips as it was back when it was a 400Mhz G3 board I have not replaced those or anything.

BTW I noticed on both the Pismo and my iMac with gauge pro in OS9 it will report the bus/cpu frequency a bit higher then normal for the first couple minutes of running then it will settle to steady normal 99.9Mhz Bus speed in the case of the Pismo and iMac im not sure if this is a bug in the app or really is the bus speed being a bit lose for whatever reason.

https://browser.geekbench.com/geekbench2/2625681


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Gave it another reflow. the L2 cache still not showing up/is reporting cache failure in POST messages. I dont want to keep reflowing the board as it is getting kinda crispy so to speak so ill just leave as is a 600Mhz G4 Pismo with no L2 cache LOL tho maybe if i can learn how to reball i might lift the chip reball it clean up the pads again and give it another go as I highly suspect its a dodgy ball under the CPU and not the L2 chips. but apart from that the thing is still nice and stable at 600Mhz :)
 
Perhaps the bad connection is on one of the cache chips?

If you do get into re-balling stuff I'd be interested in hearing how it goes!
 
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I am happy to report some good news in regards to my Pismo that I upgraded the CPU on


as I mentioned in my other posts in this thread, while the CPU Swap went well it seemed the L2 cache did not want to work. a few weeks later i decided to give the 7410 a reflow to see if it would fix the L2 cache issue...


while that did fix the L2 cache issue it was only temporary as soon after the L2 cache died again... but this did tell me that it was an issue with one of the BGA Balls.


so fast forward a bit and on the advice of max1zzz I recently got some MUCH better solder Flux, with this in mind i decided to try another reflow to see if i could permanently fix my L2 cache issues using the new flux


so I applied a ring of this flux around the CPU and used the hot air gun to push it under the CPU and reflow the CPU in the hopes to clean out any crud and stuff from under the CPU and help the dodgy ball(s) reflow into place. and man during the reflow you should of seen all the nasty old flux from the original CPU swap come out from under the CPU, it was fun cleaning that off of the PCB :) after i had finished letting it cool down i had a look at the BGA balls under the CPU and they looked much better then before so the new flux i got seemed to of done a good job and when i put the CPU card back into the Pismo and fired it up Bingo i was greeted with working L2 cache! and this time it seems to be holding as well :) i was able to complete a geekbench run in leopard with no issues :D https://browser.geekbench.com/geekbench2/2631615

overall this Pismo is now quite snappy with its 600Mhz 1MB L2 G4 :)

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Thanks :)

the flux I use is NC-559-V2-TF as i said it works Really well :) just make sure to get the real stuff theres a lot of fakes on the market out there...

as for my next project not sure atm... Both the iMac G3 and the Pismo are now fitted with G4 CPUs and i dont own any more G3 Macs to fit G4s to :) if I get a suitable clamshell ill prolly try and solder a 7410 to that, I have a nice 533Mhz 7410 removed from a DA CPU card that im keeping for something like a clamshell, I also have its L2 cache chips as id like to see if upgrading the L2 cache on macs with 512KB of backside L2 is possible (I do have a PowerBook G3 Kanga but thats quite rare and has some added hurdles when it comes to fitting a 7400/7410 mostly to do with Core and L2 cache voltage, so I probably wont be fitting a G4 to my unit, unless MAYBE if the mentioned hurdles are overcome) id also like to try a suitable Tray loading iMac G3 at some point but i dont own one of those yet :)

one project id like to try is replacing the 603ev in my PowerMac 4400 with an MPC740 they are pin compatible :) but thats a case of finding a suitable MPC740...

I have quite a few ideas id like to try as well, but I either lack the machine or the CPU to do so, its quite hard to find Bare PPC CPUs, mostly those being the ones NOT used by apple (750GX 7448 740 etc), the ones used by Apple can easily be removed from a non functional logic board of some kind (replacing the 7445 in say a 1.25Ghz iMac G4 with a 7447 of some kind, would be an example of a project id like to undertake but lack the machine to do so)
 
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