mdd 1.25 cpu to dual 1.25 no boot problem

[toadstr]

I have a working 1.25ghz mdd g4 that i want to put a dual mdd 1.25 cpu into. When i try booting with the dual installed all I get is a black screen, fan speeds up after 10-15 sec. I got the cpu on ebay, it was listed as pulled from a working unit. I have tried resetting the pmu? with no luck, batt. is good. Any ideas?

thanks for any help you can give...
toadstr http://images.macrumors.com/vb/images/smilies/cool.gif

 

[pm7300]

Hi. I did the same thing on my G4mdd 1,25 single. I removed cpu card and
put a dual 1,42 from a fw800. The machine runs perfectly, on first boot I remember I just zapped Pram, but booted fine and sysprof reports now dual cpu G4 @1,42Ghz 2mb L3 per cpu. Though I was sure the cpu was right working, when I did it I crossed my fingers.....
Does your Mac make any acoustic signal when you try to boot?
Have you tried by re-install the old cpu, start, shut down and then going again to the new one?

Rob

 

[toadstr]

Yes the old cpu works fine when reinstalled, I even tried the same thing you did with yours and no joy. No noise on boot just black screen. All the bus speed settings should be the same correct? All I should have to do is install the cpu and reboot, right? again thanks for any help you can give
toadstr

 

[pm7300]

Hi again. Yes, it should be just a plug and play,If your Mac with the old cpu shows 167mhz bus speed. If speed is the same I suggest you to return the card to the seller because not working, return even if speed doesn't match because this case isn't compatible with your mdd.
You can look at Sonnet MDX dual 1,8 for upgrade. I think boosting up from a single 1,25 to a dual 1,8 would be a good deal. I should like to do the same with my G4, but it's a dual 1,42 2mb L3 per cpu, so the difference with dual 1,8 MDX (without L3) will change nothing or too few, and it's not worth the cost. I'm still waiting to know about Newertech upgrade G4 7448, some months ago they told me there's a slight chance they'll produce an upgrade
for mdd's like yours and mine.
Rob