Dell xps m1330 fan diode shorting

[Isakosh]

Hi,
I had the usual C10 problem with the motherboard.
After replacing it i found out that the fan is not starting on power-up.
I found out that removing D27 diode fixes the problem.

as far as i can see from the schematic the diode is for protection.
am I right? can i work without it? (the fan now works and the computer boots).

Schematic attached
View attachment dell1330_7069.pdf
Thanks.

 

[BradtheRad]

Your link is to a large document which contains a great many diagrams. It would be better if you extract one or two schematics, and post those. Then readers will have an easier time in answering your query.

 

[betwixt]

Its on page 24.

The diode is only for protection but I would be wary of leaving it out. I think it's purpose is to prevent the fan 'overspin' generating a reverse voltage back to the driver IC. If removing it fixes the fan problem then either the diode is shorted or fitted backwards. Note that it is a Shottky barrier diode with Vf of 0.37V so don't replace it with a normal silicon diode.

Brian.