Bad news: MacClip Jr tanks with 601 card

[ClassicHasClass]

I was hoping that the 601 Power Macintosh card in my Quadra 800 would go from 66 to 80MHz when I clockchipped the Q800 from 33 to 40 (since it will run at 80 in the 840AV). Alas, after a startup sound and a pause, it then goes into the chimes of death.

(Incidentally, since I don't see this documented anywhere: for the 4-DIP Mac Clip Jr, the 4 switches correspond to the leftmost 4 in the clock speed chart in the manual, starting with 38MHz { all down }, so 40MHz is dn up dn up.)

However, 8.1, 7.6 and A/UX are all very happy with the 40MHz upgrade -- even though Clockometer crashes in A/UX, Speedometer indicates an appropriate boost. So rather than having a crummy PPC running 8.6 occasionally, I'll just stick with a kick-ass 68040 running A/UX and 8.1 most of the time (and maybe 7.6 now and then).

 

[trag]

I was hoping that the 601 Power Macintosh card in my Quadra 800 would go from 66 to 80MHz when I clockchipped the Q800 from 33 to 40 (since it will run at 80 in the 840AV). Alas, after a startup sound and a pause, it then goes into the chimes of death.

Well, if it makes you feel any better, I found that the Turbo601 would not run any faster than about 34 - 35 MHz bus speed in the IIci. To overclock it I had to change the clock multiplier to the PPC601 chip.

Your case is more unexpected, given that the same card will operate faster in a different machine, but perhaps the logic is detecting its host and adjusting a PLL accordingly.

 

[ClassicHasClass]

That's the only thing I could think of. I was really hoping the card simply had a 2x multiplier on the board clock signal, but it appears this is not the case.

 

[ClassicHasClass]

Interesting: http://lowendmac.com/chip/quadra.html alleges if you run the main oscillator a bit slower (38MHz is a valid setting on the MacClip Jr), the PPC card will work at around 77MHz. That's worth trying except I've got the Q800 all happy in its new enclosure. Anyone tried this?