[SOLVED] Weird behaviour in motherboard repair

[mlefe]

Hi guys, i'm trying to repair a laptop that has a fan that doesn't work.
When I measure resistance between an IC pin and the VFan_OUT pin on the fan connector I have a short (as expected) but when I connect the fan and measure again I can read more than 50K and raises until it OLs the meter (like if I was measuring a cap)... this is completely unexpected as I don't see how adding something can change the previous short... what am i missing? Thanks!
 

[Shock]

Hi guys, i'm trying to repair a laptop that has a fan that doesn't work.
When I measure resistance between an IC pin and the VFan_OUT pin on the fan connector I have a short (as expected) but when I connect the fan and measure again I can read more than 50K and raises until it OLs the meter (like if I was measuring a cap)... this is completely unexpected as I don't see how adding something can change the previous short... what am i missing? Thanks!

So are you saying, you're measuring a low resistance trace on the PCB and getting an odd measurement when you connect the fan?

Do you have a link to the schematic and is there any power/battery connected to the circuit or charged caps etc?

[IanMacdonald]

Sounds like a residual voltage upsetting the meter.

[amyk]

You have the leads touching something slightly different, and a cap is being charged up by the meter's test voltage.

[mlefe]

I feel embarrassed, it was a very dodgy connection, nothing else 

Thank you all!