TX2 motherboard 504466-001 low voltage

[learnix]

Hi,

i have HP touchsmart tx2 laptop , identified as per below screenshot the voltage at the PQ36 is coming low 1V but not sure can someone confirm if i am on the right track

Emitter is 18+ , Base and Collector are not giving 5V .. can someone please advise as per the picture.

secondly this motherboard was previously repaired and some other transistor is in place not "IRFR3709" but before i go and purchase i want to make sure i am right about the voltage i have confirmed with another TX1 board and on that the voltage at this transistor is In 18V Out 5V which is making me think that this is the faulty transistor.

please advise thanks a lot

[learnix]

Re: TX2 motherboard 504466-001 low voltage

forgot to add the screenshot.

[u271D]

Re: TX2 motherboard 504466-001 low voltage

I don't see PQ36 on your upload, and you said its not IRFR3709, so what do you have?

[learnix]

Re: TX2 motherboard 504466-001 low voltage

sorry its PQ37 getting voltage from charger to the IC i have inserted second screen as well. as for IRFR3709 , i need to go back and check on that transistor i will add the voltages that are out as well but after few hours thanks a lot

[cyberhack]

Re: TX2 motherboard 504466-001 low voltage

page 39 pq37 is zener check if short if remove it

[learnix]

Re: TX2 motherboard 504466-001 low voltage

thanks my question was raised after reading from this schematic do you understand PG 39 voltages and how to confirm expected voltages on point 1 / 4 / 3 on PQ37 just to identify if this is working as expected or not .

regards.

[cyberhack]

Re: TX2 motherboard 504466-001 low voltage

pin 4 should have input 19v
pin 1 control voltage
pin 3 output 19v
control voltage comes from pu9
you could short pin 4,3 to see

[learnix]

Re: TX2 motherboard 504466-001 low voltage

hi i have 15N03GH , i do not understand replacement transistor but the voltages are 1 volt on 2 pins and 19V

[learnix]

Re: TX2 motherboard 504466-001 low voltage

Adding transistor pic