HP 250 G5 death

[shybear]

hi,
I've a weird problema with this laptop tha t mount a BDL50 LA-D704P rev:1.0 mainboard.
If I attach powerthe led near power connector doesn't light on and just sometimes its visible a periodic spike of 0,04A for a second next 0A again.
There is nothing burnt and if I test the voltage at PQ202 main mosfet I get 19V but on the exit of it there is nothing.
So without desolder it I just bypassed PQ202 putting 19V directly on PQ203 and alls works fine.
So I desoldered PQ202 that looked to be good with tester but I changed it anyway with a new one.
It doesnt' solve the issue and with the new one I've the same problem.
There isn't so much components mounted and the only thing that could be is that PC201 is shorted but on mainboard its not printed. So I tested capacitors around here but it seem to be all fine.
If I bypass PQ202 all works (I tested the boot too) but I think its not safe works without it.
I attach a picture of the zone and also the complete schematic for reference.

[mon2]

Re: HP 250 G5 death

Review the following voltages to ground:

REGN

ACDRV

ACOK

Of the charger IC at PU201. Post each measurement.

The fault is likely in PQ203.

[shybear]

Re: HP 250 G5 death

Review the following voltages to ground:

REGN =>5.73V

ACDRV => 0V

ACOK => 0V

Of the charger IC at PU201. Post each measurement.

The fault is likely in PQ203.

I also checked PQ203 (right now without desolder it) and it seems to be fine.
I just checked again all small capacitors around PQ202 and no shorts.

[mon2]

Re: HP 250 G5 death

Remove PR208 (~4k ohms) and check if the ACDRV voltage boosts to ~25 volts at the charger IC pin # 4.

[mcplslg123]

Re: HP 250 G5 death

How you are measuring PQ202/203?? In resistance mode set your meter to highest scale and measure between

01.PIN1-pin4
02.Pin1-Pin8
03.Pin4-Pin8

[shybear]

Re: HP 250 G5 death

How you are measuring PQ202/203?? In resistance mode set your meter to highest scale and measure between

01.PIN1-pin4
02.Pin1-Pin8
03.Pin4-Pin8

Thanks, yep if I'm right gate must be isolated from drain and source and also I tested between IN(pin5-pin8)- OUT(pin1-pin3) in diode mode.
I bought anyway PQ202 (same as the mounted one) even if the original one tested with tester was fine.

[shybear]

Re: HP 250 G5 death

Remove PR208 (~4k ohms) and check if the ACDRV voltage boosts to ~25 volts at the charger IC pin # 4.

Following your direction I removed PR208 (4,12K) but ACDRV is still 0V.
If I inject directly 19V on the OUT(pin1-pin3) of PQ202 I measure 25,6V on gate (pin4).

[mon2]

Re: HP 250 G5 death

Resistance mode, not diode mode.

Post each measurement.

Remove pq201 and test again. The 4k resistor should be put back on the ACDRV pin.

[shybear]

Re: HP 250 G5 death

Resistance mode, not diode mode.

Post each measurement.

Remove pq201 and test again. The 4k resistor should be put back on the ACDRV pin.

PQ201 its not mounted on this mobo!

[mon2]

Re: HP 250 G5 death

Resistance mode, not diode mode.

Post each measurement.

Also, for:

REGN =>5.73V

Where did you attach the adapter voltage ? Or is this with the bypass of PQ202?

Are you using the original and recommended power adapter for this laptop?

[mon2]

Re: HP 250 G5 death

What is the voltage to ground of ADP_SIGNAL ?

This voltage is used to detect if the correct adapter is mated to the dcin connector or not.

If it is the wrong range, then ACDRV will not be boosted.

The bypass trick is also bypassing this adapter checking logic.

[mcplslg123]

Re: HP 250 G5 death

The OP is drawing his own conclusion without mentioning the measurements going by the reply at post#6. Its not possible to suggest anything worth without suggestions not being answered completely/vaguely.

[shybear]

Re: HP 250 G5 death

What is the voltage to ground of ADP_SIGNAL ?

This voltage is used to detect if the correct adapter is mated to the dcin connector or not.

If it is the wrong range, then ACDRV will not be boosted.

The bypass trick is also bypassing this adapter checking logic.

Man you're a genius!!!
I didnt't know this type of adaptor is smart power and you're 100% right.
I just tried with an original power adapter for and HP Spectre and even if this one is just a 45Watt, if I connect it to power jack the led light on!
Really thanks so much for help!!!

[shybear]

Re: HP 250 G5 death

The OP is drawing his own conclusion without mentioning the measurements going by the reply at post#6. Its not possible to suggest anything worth without suggestions not being answered completely/vaguely.

First of all thanks! I know you wanted to know if I was right to say that mosfet are ok, so I was not so specific just to explain how I test these components.
Anyway for future reference help:
pin 1-2-3 => SOURCE
pin 4 => GATE
pin 5-6-7-8 DRAIN
so if the component is good GATE must be isolated for drain an source, so:
pin1-pin4 =>infinite
pin8-pin4 =>infinite
Between source and drain there is a junction so I usually test it putting tester under DIODE mode then:
pin1-pin8 must be around 0,5/0,6V direct and inifinite in the reverse.

[mon2]

Re: HP 250 G5 death

https://electronicsbeliever.com/how-...-is-defective/

[mcplslg123]

Re: HP 250 G5 death

First of all thanks! I know you wanted to know if I was right to say that mosfet are ok, so I was not so specific just to explain how I test these components.
Anyway for future reference help:
pin 1-2-3 => SOURCE
pin 4 => GATE
pin 5-6-7-8 DRAIN
so if the component is good GATE must be isolated for drain an source, so:
pin1-pin4 =>infinite
pin8-pin4 =>infinite
Between source and drain there is a junction so I usually test it putting tester under DIODE mode then:
pin1-pin8 must be around 0,5/0,6V direct and inifinite in the reverse.

Thanks for clarifying but still prefer to check mosfet in resistance mode and not diode mode. A slightly leaky mosfet(not shorted) can only be detected when you measure it in resistance mode.Diode mode readinf may misguide you at times.