On 2003-02-16 05:08, "Andrew Kershaw" <[EMAIL PROTECTED]> wrote:
>> Damn. All this talk of 500-series PowerBooks is making me want to go to the >> attic and put my NetBSD running, 68040 upgraded, 90 MHz 540C back into >> action, instead of writing code, like I should be doing... :-P > > Whoa, did you say 90MHz? Do you mean 90/45 (as usual speed nomenclature for > 68040s is 50/25MHz, 66/33Mhz, 80/40Mhz, core clock be 2x the bus interface) or > do you mean your CPU is genuinely running at 90MHz?! If so, how'd you manage > that? Even the 68060 didn't go that fast. Besides, the '040 doesn't support > clock multipliers like the PowerPC, so you'd also need a 90MHz bus to run a > 90MHz CPU (all '040 macs run 1:1) Okay, I should explain. It is indeed, as you said, running at 90/45 Mhz. Less, even, but I like to round things in my favour. :-P > It should be noted that the 68040's clock input runs at 2x the actual speed of > the CPU, hence the dual speed nomenclature. A 66/33MHz 68040 is really only a > 33MHz part. I know. I just list it as 90 MHz to get a *wow* effect... I also still say the CRT monitor I use at work is a 17" one, even though it only shows 15.8 inches of true screen real estate. > Still, intriguing. I'll bet you clocked your bus to 45MHz with a 80/40MHz > 68040 installed. ;-) That's exactly it. The process is pretty much outlined here: <http://www.wwc.edu/~frohro/520_Fixes/520_&_540.htm> Although I would recommend that you don't try to unsolder the old 68LC040; instead just take a very sharp knife and cut off its legs. The old part is useless anyhow, and you'll be less likely to destroy any circuit traces by heating them for too long with a soldering iron. I used to work at a place where we used QFP 68040's in production, and I can assure you we didn't pay $216 a piece for them! And I didn't pay anything for mine... It was pretty much old stock they were getting rid of. I did get to use their nifty hot-air SMD soldering equipment, although the job could just as well be done with a very fine-tipped soldering iron. Overclocking is done by replacing the oscillator crystal on the daughter card with a 20-22.5 MHz part. 22.5 MHz results in the maximum speed of 90/45 MHz, but you might want to go a little lower if you get freezes and crashes. Basic info is here: <http://homepage.mac.com/schrier/mhz.html> I seem to remember there was more elaboration on how to do it on the 500 series, but that may have been on another site. It's a long time ago, memory is fussy on those things. I did it after moving up to a 1400, and I am now on an iBook which is about to be replaced by a 12" AluBook... So I haven't given the matter much thought lately. I seem to recall Sonnet at one time selling 80/40 MHz 68040 upgrades for the 500 series... Can anyone confirm this, or was I dreaming at the time? I can's imagine they sold a whole lot of those, since the PPC upgrades were available too, by that time, but it would have made sense... After all, the 840AV (80/40 68040, fastest 68K Mac ever) was faster than the early PowerMacs when running 68K code. ,xtG .tsooJ -- 011110010110111101110101 011000010111001001100101 01100100011101010110110101100010 -- Joost van de Griek <http://www.jvdg.net/> -- PowerBooks is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Enter To Win A | -- Canon PowerShot Digital Cameras start at $299 | Free iBook! | Support Low End Mac <http://lowendmac.com/lists/support.html> PowerBooks list info: <http://lowendmac.com/lists/powerbooks.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive: <http://www.mail-archive.com/powerbooks%40mail.maclaunch.com/> Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
