PowerBook 2400c clock chipping

[Franklinstein]

I was entertaining the thought of experimenting on a 2400c, and the only thing stopping me is the fact that I can't figure out how the clock frequency of the microprocessor is controlled. I'm hoping it's a series of resistors or something similar located on the processor board, but none of them seem to be laid out in a fashion similar to other machines like my WallStreets.

Any thoughts?

 

[alk]

Danger, Will Robbinson!

2400c parts are precious. It is your machine, so clearly you can do with it what you like, but I wouldn't. The 2400c parts are expensive enough already, so unless you have some spares on hand just in case, I don't think it's worth the risk.

If you do have any spares, wanna sell me a keyboard? Mine's missing the F4 key.

Peace,

Drew

 

[Franklinstein]

I'm not noob enough not to realize the rarity of parts for the 2400c. I have another one with a bad power board that I need to fix and/or replace. Any thoughts on what may be bad on that?

I'm only experimenting because I have a processor board with a bad processor. I'm good enough that I can remove and replace the bad chip with a faster one, thus I would like to know how to change the clock frequency accordingly. No sense using a 300MHz 603e if it'll only run at 180MHz (although it might run comparatively cooler than the original).

No spare keyboards, I'm afraid. Except for my close-to-pristine prototype model, all of my 2400 keyboards are noticeably worn anyway.

 

[Byrd]

Ideally you'd want to compare the PCB of both the 180Mhz part to the 240Mhz part - to see if a block of resistors exist that allow you to adjust the mutiplier. Since most 603e-era Macs are overclocked this way, I'd be hopeful that this is the case.

On the other hand, with the 2400c being very similar to the 3400c, the only thing I could find on 3400c overclocking was on replacing the clock crystal (perhaps easier to achieve?):

http://www.danpalka.net/hooper/

Another consideration is the 603e's don't overclock that well, so even if you did find a way to do this, overclocking the stock CPU will only give 10 - 15% increase at most. As for replacing the CPU - so you have access to an SMD rework station?

With regards to your faulty power board, the same SMT fuses that cause the infamous "GLOD" on 2400c also exist on the power board, so run a continuity test over them to see if they are working or not.

Do you have any pics of your prototype 2400c? Love to see it. I was lucky enough to repair two 2400cs earlier this year (required painful SMT fuse replacement), and kept one, which has become my most treasured Mac of all - very very few in Australia.

JB

 

[alk]

The fact that there isn't any information on the web about overclocking a 2400c doesn't mean it can't be done. The same applies to the resistor matrix on the 3400c.

On the 3400c, I'll bet you real money right now that the resistors you need to move around are R163 - R177. They reside beneath the PMU on the main logic board. In fact, maybe I'll take a crack at it and post my results on my webpage like I did the 5300...

Marc Schrier's page is always a good place to look for information on overclocking. http://homepage.mac.com/schrier/mhz.html I just looked, but I didn't find any information about the 2400c there. The 3400c overclock info that he has is about changing the bus speed, not the multiplier.

I've got what is purported to be a 2400c/240 prototype (actually, it appears to be a developer's seed model - it is a 240 MHz unit, but it is labeled as a 180 MHz unit, and it has the MacMedics and PowerBook Development Team stickers on the bottom). I haven't cracked it open yet. I'm actually a little intimidated by it - 2400cs are just so precious, and it took me years to find a 240 MHz model...

FWIW, I've learned to take Dan Palka's claims with a grain of salt. There were plenty of people before him who overclocked their PowerBooks (just see Marc Schrier's page for proof). What is more, he didn't take the time to buz out the resistor matrix. He could have had a far more impressive hack (a coup de grace if you will) if he had done the double whammy bus overclock and multiplier adjustment to squeak out max bus speeds and CPU speeds at the same time.

Peace,

Drew

 

[Franklinstein]

I have no problem posting pix of my proto-2400c. I just kind of need somewhere to do it, so question: should I create a Flickr account? How many other people on here have one? I already have a MySpace, but I typically use it to rant about stupid people, computers, video games, and zombies, so nobody ever goes there (I only have 10 "friends"...). I don't have a reason to open my own web site, but if I did, I would definitely have multiple shrine-pages to awesome things, like the PowerPC 750, MiniDisc, Kei cars, cars I've owned, cars I lust after, and Half-Life.

As for o/c'ing my 2400, I'm afraid it's most likely going to be like the 1400: multiple resistors spread all over the place in no readily discernable fashion. I may be able to figure out what pins on the 603 chip accepts the clock signals and work backwards, but it might be hard to trace traces on a multi-layer circuit board... I unfortunately don't have a 240MHz model to look at, so a comparison is out (unless some kind soul posts a picture of theirs).

I did some voltage tests on the old power board, and it had some odd readings at the power jack. On the same pins, the bad power board registers approx. 25v, while a good board reads about 16v. There are other anomalies near the motherboard connector, but that's the biggest one. I don't think it's just a simple fuse, unfortunately. These computers have more post-production factory modifications than almost any other Mac I've ever seen, so it's possible that one of those might have come undone.

 

[defor]

I'd love to see pics of a proto 2400c... flicker would be the best route i'd suggest, especially given the few of us posting to the prototype apple pool:

http://www.flickr.com/groups/apple_prototypes/

 

[tomlee59]

On the 3400c, I'll bet you real money right now that the resistors you need to move around are R163 - R177.

Details on the 3400c can be inferred from here:

http://mywebpages.comcast.net/macdan/images/pb3400resistors.jpg

It shows configurations for 4.5x, 5x, and 6x multiplication ratios. The bus speed is controlled directly by the crystal. Although I don't know for a fact that there's no other way to change bus speed, I strongly suspect that changing the crystal itself is the only method, as ratios close to 1:1 are inconveniently generated.

 

[Trash80toHP_Mini]

BUMP! :lol: LOL!!!! I found this thread Googling info on chipping a QFP 180MHz 603e! 8-o

Does anyone know if the 603e came in QFP at speeds faster than 180MHz and a relatively inexpensive source for such a beast of a QFP Proc? However if I can find a faster part that'd be way cool! On second thought, HOT might be a better adjective for it! [}] ]'>

Mostly, I'm interested in what Kluged Multiplier to use on the 180MHz 603e I've already sourced to get the most out of it on a (native 3x Multiplied) 33MHz Bus.

Got info? :?: