Now I have a really insane question, if I do the plumbing right, could I run my system using only one pump?

Yes one of the pumps just up and died on my after the PCB released the magic smoke and burnt itself (see pictures). Now I think that I have found a replacement PCB, but I would like some help identifying if it will work and also if anyone might have some spare units or something like that, or even a place I can get the parts cheap(ish, basically not $70 to $400).

In the mean time I got to thinking and believe that I have mapped out a loop that could feed both loops from one pump, now I know that there might need to be some wiring modifications done, but I was just wanting to know if I would be able to pull this off and have it run just fine, or if it would burn the motor out? Also would adding a resistor to the wires to bring the voltage down to 10v - 11v be OK too?

OK!!! Update this is my plan for a single pump dual loop. Please excuse how crude it is, I am needing to get proper tubing (and maybe fittings and joints and maybe even pipe), but I want to know if this would work at all. So I will just do a quick test to see if it can pump water through it.

Please if anyone knows if this will work please let me know ASAP.

I did find some other threads in google of other people using alternate pumps (other part numbers), but I have not seen anyone convert a dual pump to single pump. In theory it should work as long as the pump can keep going. @HrutkayMods has several G5 videos on Youtube about converting LCS to air cooled as well.

>> phunguss said:

I did find some other threads in google of other people using alternate pumps (other part numbers), but I have not seen anyone convert a dual pump to single pump. In theory it should work as long as the pump can keep going. @HrutkayMods has several G5 videos on Youtube about converting LCS to air cooled as well. Click to expand...

What pumps can I use? Is it able to be any type of pc pump? Also where would I get the air cooled heatsinks?

>> phunguss said:

I did find some other threads in google of other people using alternate pumps (other part numbers), but I have not seen anyone convert a dual pump to single pump. In theory it should work as long as the pump can keep going. @HrutkayMods has several G5 videos on Youtube about converting LCS to air cooled as well. Click to expand...

Also it was kinda working bleeding the system is a nightmare. And I also found out that the pmv PCBs die because of a particular component.

I will look into the pump options.

>> Cyclone740 said:

What pumps can I use? Is it able to be any type of pc pump? Also where would I get the air cooled heatsinks? Click to expand...

There is a ton of stuff out there...

http://tenfourfox.blogspot.com/2021/07/and-now-for-something-completely.html
https://forums.macrumors.com/threads/comprehensive-guide-to-servicing-g5-quad-lcs.2455017/
https://68kmla.org/bb/index.php?threads/quad-g5-lcs-overhaul-pump-replacement-pwm-dependant.39750/
https://inverary.net/LCS/Power Mac G5 Quad LCS Restoration, A-Z Guide, v1.0.pdf

Air cooled conversion would likely require salvage from another air cooled G5, or parts units off your favorite reseller site.

>> phunguss said:

Air cooled conversion would likely require salvage from another air cooled G5, or parts units off your favorite reseller site. Click to expand...

There's a couple Quad G5 air cooling threads on MacRumors. They use third party air coolers - 92 mm.

>> joevt said:

There's a couple Quad G5 air cooling threads on MacRumors. They use third party air coolers - 92 mm. Click to expand...

Could you maybe link that thread?

>> Cyclone740 said:

Could you maybe link that thread? Click to expand...

These are the recent ones:
https://forums.macrumors.com/threads/because-i-can-air-modding-a-quad-with-pc-coolers.2427612/
https://forums.macrumors.com/threads/air-cooling-a-late-2005-g5-quad.2455900/
https://forums.macrumors.com/thread...to-converting-g5-quad-to-air-cooling.2457994/

Maybe you can google other sources that I don't remember.

>> joevt said:

These are the recent ones: https://forums.macrumors.com/threads/because-i-can-air-modding-a-quad-with-pc-coolers.2427612/ https://forums.macrumors.com/threads/air-cooling-a-late-2005-g5-quad.2455900/ https://forums.macrumors.com/thread...to-converting-g5-quad-to-air-cooling.2457994/ Maybe you can google other sources that I don't remember. Click to expand...

Thank you so much for this information, I am sorry for asking this information of you when I should be able to find it myself, the problem is that I find it very difficult to sift through information effectively without going down like 5 different rabbit holes.


Also if you don't mind me asking, do you know if the replacement PCBs from DIYINHK with the PWM will work as drop in replacements for the old ones? And if not is there a write up or a guide showing or explaining how to make it work with the G5 PWM? Like is it just a matter of swapping a chip from the old board onto the new one? Or what do I do?

>> Cyclone740 said:

Also if you don't mind me asking, do you know if the replacement PCBs from DIYINHK with the PWM will work as drop in replacements for the old ones? And if not is there a write up or a guide showing or explaining how to make it work with the G5 PWM? Like is it just a matter of swapping a chip from the old board onto the new one? Or what do I do? Click to expand...

I don't know anything about that. The PCBs from DIYINHK are not mentioned in the air cooling links I posted.
They are mentioned here:
Past summer project - G5 Quad LCS rebuild
LCS Issues Late 2005 Quad