Power Mac 6100 Crescendo Hack

[Phipli]

I've read that some guys did it successfully ...

If we check this reference web page, it seems to be almost impossible: https://kan.org/6100/cpu.html

This page has useful info :

Clock Chipping

www.applefool.com

Including stats on how well people did overclocking.

 

[Trash80toHP_Mini]

I've read that some guys did it successfully ...

If we check this reference web page, it seems to be almost impossible: https://kan.org/6100/cpu.html

You guys got me interested enough to pull the 6100/60 out from under a pile of binders and other crap. So far I only see physical limitations to the G3/HPV combo due to cubic interference with the standard 3.5" HDD mentioned in the docs. One look when I popped the lid had me remembering plans to use one of my 2.5" SCA drives a decade ago. No problem in terms of cubic there, but SD developments over the years negate power/cooling budget concerns I had at the time related to use of the little server drive.

Clock Chipping
Including stats on how well people did overclocking.

Overclocking stats seem to be related to OEM CPU constraints. No concerns there when using a G3 card AFAIK? The 601 sleeping on the logic board doesn't enter into the equation at all with the G3 card present.

Power/cooling remains an issue, but that doesn't look to be much of a problem given 3D printing developments since I last looked into this. Plenty of cubic is available behind the blank section of the backplane plate adjacent to the HPV's DA15 connector. A printed replacement for that plate incorporating mounting points for a centrifugal blower (squirrel cage) ducted for exit at the rear takes strain off the OEM fan, improving cooling significantly. Ducting on the intake side pulling air straight across the G3 Card's heat sink directly from the intake vents underneath the HDD bay should make things much better on the cooling front.

Centrifugal blower tech has come a long way in terms of efficiency and noise dampening. They're in everything now including your laptop today. No worries there. The original SE's cooling utilized a bypass fan, not a "Squirrel Cage" design, so don't bring up that example.

In terms of SD card and air dam induced by the dog legged cable run to CD/HD and above mentioned interference with the OEM 3.5: HDD, we can do a lot better I think. Looking into a carrier board for an SD solution that plugs directly into the internal SCSI connector that provides for a straight, flat cable passthru run to the CD connector makes sense to me. Eliminating SCSI cable to the HDD bay will improve airflow.

Implementing a sensor on the G3 heat sink with speed control circuit for the rear blower mod seems like a nice project as would be coming up with the printed bracket. Such would be implemented on the SD carrier/passthru PCB. I don't do the modeling/printing or electronics sides of these things, I just come up with crazy ideas.

Dunno, I think we have solutions available now that render HPV fitment problems mentioned in the docs moot, even improving upon power/cooling budget limitations of the stock 6100.

 

[Phipli]

Overclocking stats seem to be related to OEM CPU constraints. No concerns there when using a G3 card AFAIK? The 601 sleeping on the logic board doesn't enter into the equation at all with the G3 card present.

Ocerclocking doesn't only overclock the CPU, it overclocks other parts on the logic board. But... what you've done there is gone to the page about the 6100 when I linked a site that includes overclocking Sonnet Nubus upgrades

Centrifugal blower tech has come a long way in terms of efficiency and noise dampening. They're in everything now including your laptop today. No worries there. The original SE's cooling utilized a bypass fan, not a "Squirrel Cage" design, so don't bring up that example.

I'm not sure I'd call the fan in a laptop a squirrel cage? They're centrifugal, but not squirrel cage. Squirrel cage fans are called that because they look like a cage for squirrels, same as squirrel cage motors, independently, do. This is a squirrel cage fan :


From my house heating system. It has a shaded pole motor on the left - very reliable but inefficient. The bearings have worn out in these ones so I've been replacing them.

But fans is off topic and reminds me too much of the job I just quit.

Edit: For comparison, this is what most laptop fans look like inside (stolen internet picture) :

 

[Trash80toHP_Mini]

Bypass Fan like your HVAC fan.

Laptop fan is a Squirrel Cage Fan, AKA Centrifugal Blower.

Components on a 6100 board would be the same as on 7100/8100 boards I think? Economies of scale would be in effect. Putting anything else on a 6100 board would be far more expensive.

I'll take another look at the docs you linked, thanks. Appeared more an available driver for different generations of the G3 cards at first glance. Mines a NewerTech, but I have Sonnets as well.

 

[Phipli]

Bypass Fan like your HVAC fan.

Laptop fan is a Squirrel Cage Fan, AKA Centrifugal Blower.

Sigh.

 

[Trash80toHP_Mini]

Sigh as in yea or nay?

 

[Trash80toHP_Mini]

Quick search for HPV mounted blower in the 6100/G3/HPV study: https://www.ebay.com/itm/175242979363



It's a perfect size at 15mm thick as the backplane opening is 16mm wide. With the intake side pointed downward it a great fit. Can't imagine a need for it running at more then 10-20% capacity, so simple rheostat adjustment PWM controller, adding a resistor to the power line or running a two wire version at 5V should do the trick for running it without being too noisy? What's the db output rating of the SE/30 replacement fans?

I'll print it out to size at work later to do a paper model.

edit: reasons for HPV mounted blower proposal.

Finally, I emailed Sonnet myself and received the following statement:
All our cards work with the AV cards in the 61XX machines. We do not support the HPV card since it was never designed to go into the 61XX machines. We don't recommend it's use and it's design tends to cause crashing as well as overheating since it's bigger than the AV card. It cuts the air circulation down in a machine that is already not very well ventilated.

Bracket/backplane design looks like it acts as an intake vent given space around the AV card coverplate. Turning it into an outflow aux cooling setup pulling additional air through the grating underneath the HDD bay and across the G3 heatsink and HPV should alleviate HPV induced air circulation problems mentioned in Sonnet's reply?

 

[greystash]

Interesting! I've just ordered some capacitors so will experiment with fans once I've recapped it. I'll let you know how I get on

 

[Trash80toHP_Mini]

It's looking very promising. The 50mmx15mm from factor will fit easily w/o interference with the caps.





Looking into using a 60mm x 15mm blower tonight. It has higher CFM at lower dB spec. and will sit nicely atop the caps while remaining aligned with the exit.

 

[Trash80toHP_Mini]