Link removed. These are fake/remarked 66MHz chips
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Bussing around with a G3 Beige XPC106 Memory controller upgrade
- Thread starter LightBulbFun
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Link removed. These are fake/remarked 66MHz chips
I was tinkering a bit with the Beige jumper block today, and found a couple of new bus speeds that haven't previously been documented. This is assuming that Gauge Pro isn't lying – but it reports the known bus speeds of 66.8, 83.3, 75Mhz correctly, and I verified everything with Tattletech.
S=set, x=not set
60.2MHz must be using a 30MHz PCI bus and a 2x multiplier, and 78.8MHz a 31.5MHz PCI bus and a 2.5x multplier.
As regards pin 5 and 6, it seems like both Sx and SS set a 2x multiplier and both xS or xx set a 2.5x multiplier. My theory is that pin 6 is not connected/redundant.
What's weird is that according to the diagram here a 60MHz bus speed i.e. (30*2) should be set by configuring the last 5 pins as SSSSx, but no, instead it's done like I've shown above. So there is some weirdness with this jumper block – or the website has misinterpreted how it works.
By the way, there is a chip visible in your first photo of the XPC106 labelled SC608AAB. Here's a datasheet, it's a 'PowerPC 603/604 motherboard clock generator'. I'm sure it's relevant.
| Bus Speed | Pin 5 | Pin 6 | Pin 7 | Pin 8 | Pin 9 |
| 60.2 MHz | S | x | x | S | x |
| 60.2 MHz | S | S | x | S | x |
| 78.8 MHz | x | S | S | x | S |
| 78.8 MHz | x | x | S | x | S |
60.2MHz must be using a 30MHz PCI bus and a 2x multiplier, and 78.8MHz a 31.5MHz PCI bus and a 2.5x multplier.
As regards pin 5 and 6, it seems like both Sx and SS set a 2x multiplier and both xS or xx set a 2.5x multiplier. My theory is that pin 6 is not connected/redundant.
What's weird is that according to the diagram here a 60MHz bus speed i.e. (30*2) should be set by configuring the last 5 pins as SSSSx, but no, instead it's done like I've shown above. So there is some weirdness with this jumper block – or the website has misinterpreted how it works.
By the way, there is a chip visible in your first photo of the XPC106 labelled SC608AAB. Here's a datasheet, it's a 'PowerPC 603/604 motherboard clock generator'. I'm sure it's relevant.
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It should be simple to work out. Desolder the XPC106 and then beep out where the relevant pads on the BGA footprint go to.
I will do this if/when I upgrade to an XPC106ARX100, but I haven't done any BGA rework yet.
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This is a screenshot from the relevant page of the Gossamer DVT schematics, looks like we have our answer?
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hah I see you got the schematics that I was sent and forwarded onwards to my good friend who obviously forward them on to you
indeed it looks like I was bang on the money about the last 2 PLL pairs sadly im not currently in a position to mess with things, but its very promising
(also Be warned the 100Mhz MPC106/XPC106's on UTSource are fake, I mean they are real 106's but remarked, slower ones that cant clock to 100Mhz)
It’s 1000, according to the MPC106 datasheet posted earlier. Remove R52 and R49, giving access to GRKLPLL0 and 1 which should be pulled high and low, respectively. Pins 5 and 6 should be set on the jumper block, which will pull PLL2 and PLL3 low. Super easy to do.
hah I see you got the schematics that I was sent and forwarded onwards to my good friend who obviously forward them on to you
Haha, so funny!
sadly im not currently in a position to mess with things, but its very promising
That’s a pity, since the major stumbling block for me is the BGA rework needed to swap the chips over, and you already have (or had) a board with the mod done. I don’t have a board preheater. However I do have a genuine 100MHz XPC106 chip on a Yikes board and I just bought a spare beige motherboard to mess around with. I WILL do the mod.
Yep, I saw the warning over on the other forums, that’s a real shame as well!
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That sounds right, yes.
PLL(0) doesn’t go to any pins that you can set. It goes to one side of resistor R52.
Yikes, I was just about to order one, please remove the link if you can still edit it.
Technically you probably don’t have to but it’s best practice, the precise value isn’t critical but you could use a 1K or a 4.7K resistor for example.
@LightBulbFun I see you are also from London… I’m tempted to ask if I could borrow your hot plate/board preheater to do the mod 😬😉 but not sure you would be comfortable with that!!
im afraid I would like to keep ahold of it at this time
but I would ask that you dont sacrifice a nice Yikes! board for its 100Mhz Grackle, I would advise looking for a less rare/desirable Rev A blue and white board instead
im afraid I would like to keep ahold of it at this time
Of course, no worries at all.
but I would ask that you dont sacrifice a nice Yikes! board for its 100Mhz Grackle, I would advise looking for a less rare/desirable Rev A blue and white board instead
I think you might be overstating the desirability/rarity value of these boards. I picked this machine up for about £20 expressly to put the G4 ZIF into a Beige machine, so it was always my intention that it was going to be a parts machine. Preserving a machine I don't really want to keep around, that's worth almost nothing, is a lot less of a fun option than harvesting it for experimentation; in this case, quite worthy experimentation.
What is it that makes the Rev. A B/W G3 boards unreliable, specifically? If it's the ATA/33 IDE controller then this could be lifted from the Yikes board and donated to someone who needs one.
As someone has been involved in this scene so to speak for almost 10 years now! (blimey!) sadly your attitude towards the Yikes is exactly are part of the reason Yikes! are quite scarce and rare, no one on the big scheme of things, cares about them, if you want a Graphite Tower G4, your much better off with a Sawtooth GigE or DA, based on the much better, more robust and versatile Uninorth architecture , nor do they have the funky coloured case of the G3 blue and white that came before them, thus many Yikes! have just been seen as G4 ZIF organ donors for G3 Blue and White , G3 Beige, and Slocket upgrades
on top of that, I dont think they where all that common in the first place, they where only produced for a short time as a stop gap until Sawtooth could be got out the door, as above I have been involved with PowerPC macs since 2013, and I have seen many more Sawtooth's (Sawteeth?), then I have Yikes! I explicitly remember @bunnspecial really had to go out of his way to get a Yikes! for his collection
so no they are not all that desirable, but they certainly are pretty scarce and worth preserving in my opinion, and on top of that as mentioned a Yikes! board is the best form of Yosemite based motherboard one can get, as is fairly well documented, even ATA chips aside, a Rev A G3 Blue and white board, is quite the cantankerous thing, (trust me I can speak from first hand experience of that, as all 3 of my G3 Blue and White's have been Rev A units) so if you have a G3 Blue and white, that your planning seriously using/playing with a lot, you are much better off with a Rev B or Yikes! board
I would appreciate if you would spare me the judgement. You’re perfectly entitled to put across your opinion but when you phrase things like this:
it comes across as though you have some claim to ownership of my machine and that I must comply with your request. This honestly got my back up a bit, it’s kind of rude.
You don’t have to approve of what I’m doing of course but to openly criticise me on a public forum is not good form. The machine belongs to me and I have no duty to you or anyone else to preserve it or keep it as a museum piece.
@LightBulbFun Having said the above, I will consider your point of view and try to find another source for the Grackle so that someone else could perhaps benefit from my Yikes board in future. I’m not promising anything, but I’d like you to know I have heard you.
The Yikes boards are not valuable, yet, but rare. They are the pinnacle of the PCI architecture.
So those of us who hack around with PCI cards value them and hate to see good ones go under the knife.
JoeVT and I have been doing this a long time. We both had PM8600's and we wanted to get the most out of them we could. I could not justify the expense of a newer Mac, so I just wanted to see what I could get out of the old Kansas board.
Joe still has his PM8600.
Joe made the Radeon 9100 PCI, which was just a PCI version of the Radeon 8500, work in our PCI machines, and we've kind have been hooked ever since. That was over two decades ago and here we still are pushing PCI Mac's beyond anything people would have thought possible.
It's not the useful, it's just cool, it's a labor of love, so you can see why we would not want to see a Yikes board lose it's life needlessly.😅
So those of us who hack around with PCI cards value them and hate to see good ones go under the knife.
JoeVT and I have been doing this a long time. We both had PM8600's and we wanted to get the most out of them we could. I could not justify the expense of a newer Mac, so I just wanted to see what I could get out of the old Kansas board.
Joe still has his PM8600.
Joe made the Radeon 9100 PCI, which was just a PCI version of the Radeon 8500, work in our PCI machines, and we've kind have been hooked ever since. That was over two decades ago and here we still are pushing PCI Mac's beyond anything people would have thought possible.
It's not the useful, it's just cool, it's a labor of love, so you can see why we would not want to see a Yikes board lose it's life needlessly.😅