dell latitude e6540 fan solderpad gone.

[techcraze]

so i've got a dell laptop here and after about half a year i decided i'm done with the 100% fan speed 24/7
lil information this is a dell latitude e6540 revision 2016

(cause is a broken fan header solder pad on the motherboard)

the fan works fine. reporting of rpm works fine (indicated by the lovely 9.5k rpm the fan reports)

but the pwm header is broken. i removed the fan header carefully and indeed. the pwm solder pad is completely gone from the motherboard.
(no this is not my fault by removing the header. i put some jumper wires on them manually before messing with removing the header and comfirmed that it conducts from the fan to the pad beneath the header)
so i'm looking for schematics for the laptop to figure out where this trace leads too.
since this pad doesnt seem to have a visible trace running from it i cant simply follow a piece and scratch some off to solder a wire manually back to the fan.
(i'm new with reading schematics so if anyone can perhaps pinpoint me a location to where it heads that would be lovely too)

see attached pic.

black/red is the power

yellow is rpm reporting

and blue is the pwm control cable.

tomorrow i wil try to carefully scratch off some of the white paint on the board as it seems to be *easy enough* to get off to get a more clear view of the area

i have repaired boards by using jumper wires before with quite a bit of patience so i'm quite sure i can fix the pwm stuff once i find out a location i can work with

thank you all alot in advance for any tips and information about fixing this issue

 

[Diggs]

There may be something wrong with fan speed reporting. I've never seen a fan that can run at over 9,000 RPM. That's crazy fast. Personally I'd just replace the fan with something slower and quieter.

 

[NETWizz]

I would have just replaced the laptop or motherboard.

 

[Larry Sabo]

There's a schematic here but the fan circuitry seems to indicate it's wired for constant speed. You could try jumping from JFAN1 pin 2 to R30 or pin 3 to R38 to see if that reduces the speed but it's at your own risk.

 

[techcraze]

ok so i found the board id wich is la-9413p a 2014 revision actually (my old motherboard was a 2016 revision i thought dell replaced it with the same)

 

[techcraze]

There's a schematic here but the fan circuitry seems to indicate it's wired for constant speed. You could try jumping from JFAN1 pin 2 to R30 or pin 3 to R38 to see if that reduces the speed but it's at your own risk.
View attachment 11270

i wil look into it. first wanna validate that it wont short anything and break it