MindWalker
Well-known member
A small success story...
I've had my Centris 610 for almost 20 years now. As time went on I wanted to experiment with A/UX which meant I upgraded the CPU from the stock LC040 to a full 040, the part I was able to source for that was a XC68040HRC25M, ie. a 25Mhz part. As the oscillator on the board (10Mhz, gets doubled to make the CPU clock) was the same, the new CPU ran at 20Mhz just like the old one. Would be nice to swap the oscillator to get full speed, but at the time SMD soldering was not something I wanted to experiment on.
About a year ago I mentioned this in a completely unrelated thread and @Phipli gave me some more ideas (thanks!). I also read this thread by @tecneeq. Then last week as I was preparing a component order to Mouser (due to some parts I couldn't get from my local supplier) I remembered the oscillator for the Centris. I couldn't find the same package as the original (ie. preferably this) from Mouser or elsewhere, and didn't want to order from china.
But then I kept searching Mouser with the specs I had from the aforementioned link and found this SMD oscillator at 12.5Mhz. Looking at the specs it seemed to check every box it needed: 12.5Mhz, CMOS/TTL levels and runs with 5V. It's much smaller than the original but even the pinout was the same and just needed a small pieces of wire to give it enough legs to reach the pads on the motherboard. I bought two (just in case I buchered the first one) and then waited to receive the parts. Bought my Centris out of storage, and finally today I received the bag of parts from Mouser and it was time to start working!
Here's the stock oscillator (front corner of the CPU):
Stock oscillator (top, upside down) and the new part being prepared:
New part soldered to the board (a bit ugly yes, but I just wanted to test it):
And it works!
The machine has been running steadily, feels ever so slightly snappier and TattleTech shows that indeed the CPU speed went from 20Mhz to 25Mhz.
MacBench 4.0 (against the default PowerMac 6100/60) also shows a clear increase:
before: CPU score: 23%, FPU score: 8%
now: CPU score: 29%, FPU score: 10%
I am thinking about leaving this permantently in - can't see why I'd like to swap it back and I am not interested in overclocking - the 610 case is not that optimal for cooling to start with. A socket would be nice (and there is room) but I am not sure.
I've run the machine for half an hour with case open, MpegDec playing an online MP3 stream and my IR thermometer shows the CPU/heatsink is at about 40-45 degrees 'C, which sounds ok'ish I guess? I have a Nubus adapter with network card that sits over the CPU but there seems to be room - I'll see if I have any bigger heatsinks that would fit there. Just to be on the safe side.
I've had my Centris 610 for almost 20 years now. As time went on I wanted to experiment with A/UX which meant I upgraded the CPU from the stock LC040 to a full 040, the part I was able to source for that was a XC68040HRC25M, ie. a 25Mhz part. As the oscillator on the board (10Mhz, gets doubled to make the CPU clock) was the same, the new CPU ran at 20Mhz just like the old one. Would be nice to swap the oscillator to get full speed, but at the time SMD soldering was not something I wanted to experiment on.
About a year ago I mentioned this in a completely unrelated thread and @Phipli gave me some more ideas (thanks!). I also read this thread by @tecneeq. Then last week as I was preparing a component order to Mouser (due to some parts I couldn't get from my local supplier) I remembered the oscillator for the Centris. I couldn't find the same package as the original (ie. preferably this) from Mouser or elsewhere, and didn't want to order from china.
But then I kept searching Mouser with the specs I had from the aforementioned link and found this SMD oscillator at 12.5Mhz. Looking at the specs it seemed to check every box it needed: 12.5Mhz, CMOS/TTL levels and runs with 5V. It's much smaller than the original but even the pinout was the same and just needed a small pieces of wire to give it enough legs to reach the pads on the motherboard. I bought two (just in case I buchered the first one) and then waited to receive the parts. Bought my Centris out of storage, and finally today I received the bag of parts from Mouser and it was time to start working!
Here's the stock oscillator (front corner of the CPU):
Stock oscillator (top, upside down) and the new part being prepared:
New part soldered to the board (a bit ugly yes, but I just wanted to test it):
And it works!
The machine has been running steadily, feels ever so slightly snappier and TattleTech shows that indeed the CPU speed went from 20Mhz to 25Mhz.MacBench 4.0 (against the default PowerMac 6100/60) also shows a clear increase:
before: CPU score: 23%, FPU score: 8%
now: CPU score: 29%, FPU score: 10%
I am thinking about leaving this permantently in - can't see why I'd like to swap it back and I am not interested in overclocking - the 610 case is not that optimal for cooling to start with. A socket would be nice (and there is room) but I am not sure.
I've run the machine for half an hour with case open, MpegDec playing an online MP3 stream and my IR thermometer shows the CPU/heatsink is at about 40-45 degrees 'C, which sounds ok'ish I guess? I have a Nubus adapter with network card that sits over the CPU but there seems to be room - I'll see if I have any bigger heatsinks that would fit there. Just to be on the safe side.
