QS 733mhz processor installed in a DA

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Hawaii Cruiser's picture
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I was given a 733mhz Quicksilver for which I've bought a 933mhz processor to replace the 733 since you can't run Leopard on a 733mhz--at least not easily--and also because the 733mhz processor does not have an L3 cache, so it's rather pathetic in a Quicksilver. I also have a Digital Audio G4 tower running on the original 466mhz processor, so I decided to replace the 466 processor with the Quicksilver 733 processor. There is info already on the web about how to do this, but not that well documented, so I'll document my efforts, which is actually a very simple, quick mod (a lot quicker than it took me to process the photos and to write out all this). **Please note that after I accomplished this successfully the only drawback I have encountered is that the upgraded DA now does not wake up out of deep sleep. Please take this into consideration if you want to do exactly what I've done.**

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Hawaii Cruiser's picture
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Pt. 1

To begin with, I ran Geekbench to get a score for the 733 processor in the Quicksilver and got a score of 391. Then I removed the 733 processor and overclocked it to 800mhz. This is especially easy to do with the 733 version. You can read about it here:

http://powermac-g4.com/g4quicksilverclockup.html

I didn't want to bother with the risk of problems from overclocking it to 867mhz because I doubt the hassle of those probable problems would be worth it, so I just went the one step up to 800mhz. To accomplish this was as simple as can be, if you've got a good strong magnifier, a tiny sharp instrument for scratching, and a steady hand. I've got all three. All you have to do is scratch a break into the trace to the R3 jumper on the processor card. My trace scratching instrument of choice is a thin sewing needle wrapped in masking tape and mounted in a claw-style pencil holder. I use a combination of very strong reading glasses and a small strong magnifying glass mounted on a bendable arm which I made myself. The small magnifying glass is actually one of the elements I retrieved from a zoom SLR camera lens that I took apart one day because it was broken. Anyway, I simply cut the trace similar to the trace cutting described here for a DA processor upgrade:

http://www.xlr8yourmac.com/systems/quicksilver733_overclock.html

I gouge away microscopically with the needle until I feel confident the trace is actually broken. I probably overdo the gouging, but I have a steady enough hand that I'm very confident I won't accidently hit any other traces.

I then put the processor back into the Quicksilver and it booted up fine to 800mhz. I ran Geekbench and got a score of 422. Supposedly, another one of the good things about overclocking the 733 processor is that, since it doesn't have one, you don't have to worry about the clock speed of the L3 cache as well.

Hawaii Cruiser's picture
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Pt. 2

Now the processor was ready to move to the Digital Audio.

First, I ran Geekbench on the DA with the 466mhz still installed and got a score of 328 (sorry for some blurriness--I made the jpegs at the lowest resolution so this page will load faster):

Then I shut down and removed the 466 processor. I find the easiest way to unclip the heatsink is to use two screwdrivers at once--one, my phillips screwdriver to push down on the clip, and a slotted screwdriver to push under the clip and pop it off the processor board. Here's a photo of the processor connector on the DA motherboard after the processor is removed, as well as photos comparing the 466 processor with the QS 733 processor, and the two heatsinks. As you can see, the 733 heatsink has a different shape to accomodate the extra components on the 733 processor card. You CANNOT use the 466 heatsink on the 733 processor card unless you cut off a significant amount of it, which of course, reduces significantly its heat disseminating ability.

Hawaii Cruiser's picture
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Pt. 3

The only mod you have to do to a QS 733 to put it in a DA is run a 12v line to the fourth mounting hole on the processor card. That hole is not used for mounting on the DA motherboard. DA processors only have three holes. I used a molex extension cable that I cut off one end of and cut off all the wires except the yellow wire which carries 12v. Being an overly cautious person, I covered the cutoff nibs of the other wires with electrician's tape and wrapped the molex connector with the tape too to hold the other tape on. Voila:

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Pt. 4

The DA does not have a heatsink fan like the Quicksilver which pulls hot air off the heatsink and funnels it out the back grill opening, and I did not have an extra QS fan, so I worried over how provide one in the DA, especially since I had already overclocked the 733 to 800mhz, but in my haste to see if the processor would work, I just grabbed a small ZIF heatsink fan I had previously pulled from a PC and mounted it on the side of the 733 heatsink where the QS fan would normally go and used a molex splitter to provide power to the fan and the 12v mod (the DA motherboard does NOT have a power connector for a fan in that place like the Quicksilver). I then installed the processor and tried to mount the heatsink. That's when I discovered the problem with mounting a fan directly to the heatsink. It causes problems with not giving the clip enough room to do its thing, but I was able to clip it on all the same with a little trickery.

So processor in place, I booted up. No problems! The DA booted up fine to 800mhz:

I ran Geekbench, and got a score of 450! Better than in the Quicksilver (probably because of RAM differences):

While I marveled at that score I was annoyed by the sound of that little fan on the heatsink, obviously making more noise than usual because of the way it was mounted, so I shut down and took a look at it. It was mounted with two screws at the top. I was able to unscrew one screw and lifted the fan away from the heatsink a little on that side, turned on the machine just long enough to listen to it again, and it was quieter, but I also felt the wind being blown by it which was way too meager, so I realized the little fan was ridiculous and turned off the machine and attempted to remove the heatsink to get the fan off. That's when I really encountered problems unclipping because of the placement of the fan (I was not able to get a good angle with the screwdriver to get to the remaining fan screw to unscrew it). Somehow I finally popped the clip and removed the heatsink and removed the fan and then went to the garage to scrounge around in my PC-pilfered fans collection and found a fan that was exactly like the Quicksilver fan without the funnel.

This time, instead of mounting the fan directly to the heatsink, I placed a couple of pieces of rubber to mount the fan away from the heatsink--about three sixteenths of an inch--far enough to allow the heatsink clip to work regularly. For the rubber, I just grabbed one of those rectangular rubber feet that were on the bottom of a lot of old Macs--which always came off too easily, and which I kept, knowing one day they'd come in handy, and this was the day for that one--cut it in half and punched a hole into each half center and then screwed the fan onto the heatsink driving the screws through the rubber.

For a funnel, I cut some thin cardboard which I fabricated to try to match the QS fan funnel and mounted it to the fan with some double stick mounting tape.

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Pt. 5

Just for comparison's sake, I ran a Geekbench on my other 867mhz Quicksilver and got a score of 528--so the extra 67mhz and L3 cache on the QS 867mhz really do make a big difference.

I've been running the DA in many programs at 800mhz with no glitches at all, except that one big one--THE UPGRADED DA DOES NOT WAKE OUT OF DEEP SLEEP. That was actually one of the first things I tested because I suspected the possibility of that fly in the ointment all along. It does exactly the same thing as one of my Quicksilvers--when trying to wake it from sleep, you can hear the machine power up and the power button light turns to solid, but no video output at all. Well, that doesn't bother me so much as the DA is not a machine I use regularly for extended periods of time. If it was, I'd be quite bothered by the problem. My Quicksilver that doesn't wake, I've set to never sleep in Preferences, and I use that machine pretty exclusively for major time consuming converting of video files, and long burnings and renderings, so I don't want it to sleep anyway. The DA is mostly for entertainment--watching DVD's, TV, and web surfing at a desk I sometimes sit while eating, so sleep is not important there either--at least, for the machine. I turn it on, I turn it off, and now the significant speed bump to 800mhz is really an improvement.

So has anyone found a solution to the not waking from sleep? I think it's probably a fairly common problem. I tried resetting the NVRAM in Open Firmware, but no dice.

Hawaii Cruiser's picture
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Better resolution of photos

Here's the originals of the two long photo montages if you want to take a better look:

Processors and heatsinks compared

QS processor and heatsink with fan installed

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Addendum

I forgot to mention that I attached the 12v line to the fourth hole of the processor card by putting a short bolt through the hole with a nut underneath the card and a nut and washer on top to run the line into. I made sure the bolt and bottom nut did not touch the motherboard and I put a piece of electrician's tape over the bottom nut because, like I say, I'm an overly cautious guy.

Here's a photo of an original Quicksilver heatsink fan with its rubber funnel attached. This is how it looks facing toward the back grill. It actually attaches to the back grill and not to the heatsink. It's just located as if it is attached to the heatsink. Like I say, that way it does not get in the way of the heatsink clip. To remove the heatsink from a QS, you first remove the fan, and then unclip the heatsink.

http://www.applefritter.com/node/24370

eeun's picture
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Nicely done! I'd done the

Nicely done!

I'd done the conversion with a DA sometime back, but the processor I'd picked up had a bad cache.

Got a second processor eventually, and it spent most of its days clocked up from 800 to a stable 867 MHz. I installed dip switches for the clock speed adjustment, since the little resistors were so hard to get work with, and the switches allowed adjusting speed without even removing the processor or heatsink.

Sold it to fund my MDD project. As far as I know, it's still running smoothly with its new owner.

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