BOOSTA on cMP5.1 runs crazy

[handheldgames]

Does someone knows what a

nvram -c

does ?

Simple reset like holding alt opt p r - or a deeper reset ?

>sudo nvram -c
>reboot

You need the reboot to finish the process. This clears everything without having to go through the 4 restarts

 

[Ecca55]

Hi guys - I have the identical problem - cleaned, reseated and re pasted everything with no change - cannot control boostA fan with any tools either. Did you land a final solution?? Many thanks - Ecca55

 

[KeesMacPro]

did you test another fan ?

 

[Ecca55]

KeesMacpro - thanks for the feedback. I have swapped out the fan with a spare from another heatsink and the problem remained. So appears that the SMC is damaged or I have a short somewhere?? Do you know the 4 pinouts for the fan and 2 for sensor that plug into the cpu tray?? Ecca55

 

[KeesMacPro]

KeesMacpro - thanks for the feedback. I have swapped out the fan with a spare from another heatsink and the problem remained. So appears that the SMC is damaged or I have a short somewhere?? Do you know the 4 pinouts for the fan and 2 for sensor that plug into the cpu tray?? Ecca55

Hi Ecca55,

I've replaced all fans in the MP 4,1/5,1 by 3rd party fans, except for the CPU fan(s).
The OEM Delta fans for the CPU have an exceptional wide rpm range , so its hard to find an apropiate replacement.
I'm planning on testing some more though, but fact is i havent checked the pinout for the CPU fans yet.

Anyway, the fans are of a Apple 4-pin type , different from a PC 4-pin PWM .
In case you have a multimeter you could check the following on the connector:
pin1- ground
pin2- 12V constant (for a circuit inside the fan)
pin3- Tacho signal
pin4- V variable controlling the rpm
(I just called them 1-4, no pinout related)

In case e.g. the 12V constant is short circuited with the V variable, the fan will run fullspeed , no matter what the SMC dictates.

This way you could at least check if the SMC is still working correctly.

EDIT: as for the case of the OP, the sensor reading was correct, so no sensor fail , you could check with e.g.MacsFanControl if there's a correct sensor reading in your case.

 

[Ecca55]

Thanks - you can see that all the temps are fine, just that BOOSTA is maxed out - regardless of what I do with the custom setting. All other fans respond to any custom changes that I make, but not BOOSTA. I may just drop a pot/resistor into the 5v feed for the fan as a fix.

 

[Ecca55]

Just a quick update - the BOOSTA fan does spin down when in sleep mode and revs up as soon as out of sleep mode

 

[KeesMacPro]

Thanks - you can see that all the temps are fine, just that BOOSTA is maxed out - regardless of what I do with the custom setting. All other fans respond to any custom changes that I make, but not BOOSTA. I may just drop a pot/resistor into the 5v feed for the fan as a fix.

Just a quick update - the BOOSTA fan does spin down when in sleep mode and revs up as soon as out of sleep mode

Thx for the updates.

If you decide to make a voltage drop with a resistor, (obviously) the Boost A will not respond to the CPU A Temps anymore, resulting in too high T under (heavy) load or a Boost fan running constantly high...

I'm going to take a look at the fan pinout today and post it.
As a last resort , you could measure the voltage of Vc to be 100% sure the SMC is not working correctly for this fan ...

 

[KeesMacPro]

@Ecca55
I just installed a 3-pin Noctua fan as a replacement for the CPU fan, so I made a pinout of the connector, maybe it helps to check every possible cause for your issue (post#171).

Mac Pro (4.1/5.1) aftermarket fans WITH automatic SMC control

Hi, do you sell the adapter cables? :)

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