Acer Aspire 5750 no B+ voltage

[ahmetozay]

Hi, i have 19v on pq7 but only 1v output thus no 3.3v nor 5.0 v always voltages and the system is dead at the moment. in the attachment i measured the voltages at start of the B+ rail. Any advices welcome

Motherboard model is P5WE0 LA-6901P REV 2.0

[multiplexer]

Re: Acer Aspire 5750 no B+ voltage

Measure the voltages on pins 1, 2, 8, 23, 24 of PU1
Measure the voltages on all the pins of PQ14

[ahmetozay]

Re: Acer Aspire 5750 no B+ voltage

Measure the voltages on pins 1, 2, 8, 23, 24 of PU1
Measure the voltages on all the pins of PQ14

Thanks for the reply

pu1
1=5.1v
2=1.35v
8=0v
23=0
24=18.5v

PQ14
1=0v
2=0v
3=0v
4=0v
5=0v
6=6.1v

[ktmmotocross]

Re: Acer Aspire 5750 no B+ voltage

u must have short to ground on B+ rail

remove all PJP and check which powerrail is shorted

[ahmetozay]

Re: Acer Aspire 5750 no B+ voltage

u must have short to ground on B+ rail

Thanks for the reply

i thought of that and shorted the pin 1 and 8 of PQ7 but there was no short. But after your message i tried to short 1 and 8 pin of pq7 but this time with 19v and the motherboard worked ok. Thus i changed the pq7 with the new one but still output is 1v, very strange

[multiplexer]

Re: Acer Aspire 5750 no B+ voltage

Measure the voltages on all the pins of PQ19

[ktmmotocross]

Re: Acer Aspire 5750 no B+ voltage

check resistance to ground on pin 5-8 on pq7

[ahmetozay]

Re: Acer Aspire 5750 no B+ voltage

Measure the voltages on all the pins of PQ19

PQ19
1=2.6v
2=0v
3=ground

[ahmetozay]

Re: Acer Aspire 5750 no B+ voltage

check resistance to ground on pin 5-8 on pq7

Resistance is reading in mega ohms so definetely no short

[ktmmotocross]

Re: Acer Aspire 5750 no B+ voltage

did u use exactly the 4407?

[ahmetozay]

Re: Acer Aspire 5750 no B+ voltage

did u use exactly the 4407?

it was 4459 and i used 4435 instead

[ktmmotocross]

Re: Acer Aspire 5750 no B+ voltage

on your picture it is 4407

but 4459 can handle TRIPLE current than 4435 so u probably burn that 4435

[ahmetozay]

Re: Acer Aspire 5750 no B+ voltage

it was 4459 and i used 4435 instead

this board is rev 2.0 4407 is in the rev 0.1

[ahmetozay]

Re: Acer Aspire 5750 no B+ voltage

on your picture it is 4407

but 4459 can handle TRIPLE current than 4435 so u probably burn that 4435

no its not burnt still output is 1v

[atsio]

Re: Acer Aspire 5750 no B+ voltage

Thanks for the reply

pu1
1=5.1v
2=1.35v
8=0v
23=0
24=18.5v

PQ14
1=0v
2=0v
3=0v
4=0v
5=0v
6=6.1v

You have 19v and acset voltage to the charger but not acprn signal. Replace charger ic. I always replace and the fets, so I suggest replace and pq15 and pq16

[ahmetozay]

Re: Acer Aspire 5750 no B+ voltage

You have 19v and acset voltage to the charger but not acprn signal. Replace charger ic. I always replace and the fets, so I suggest replace and pq15 and pq16

Thanks for the reply

changed charger ic but there was no difference. so charging i is ok. any other advice?

[multiplexer]

Re: Acer Aspire 5750 no B+ voltage

Measures PQ19 taken according to this numbering?
See Annex
Voltages do not add up
Considering the numbering as an attachment
PQ19 pin 1 connected to pin 23 of PU1 (0V correctly stated)
pin3 PQ19 (must essera to about 3V) connected to pins 2, 5 PQ14 (0V incorrectly stated)
Pin 2 to ground PQ19
Check that the pin 2 of 3 PQ19 are not short.

[atsio]

Re: Acer Aspire 5750 no B+ voltage

I posted without reading ISL's datasheet. ACPRN should be low.
What is the voltage on pin 4 of PQ6 and PQ7? What is the voltage on pins of PQ14?

[multiplexer]

Re: Acer Aspire 5750 no B+ voltage

I posted without reading ISL's datasheet. ACPRN should be low.
What is the voltage on pin 4 of PQ6 and PQ7? What is the voltage on pins of PQ14?

Hi, i have 19v on pq7 but only 1v output thus no 3.3v nor 5.0 v always voltages and the system is dead at the moment. in the attachment i measured the voltages at start of the B+ rail. Any advices welcome

Motherboard model is P5WE0 LA-6901P REV 2.0

See attached first post

Thanks for the reply

pu1
1=5.1v
2=1.35v
8=0v
23=0
24=18.5v

PQ14
1=0v
2=0v
3=0v
4=0v
5=0v
6=6.1v

Here are the steps required

[ahmetozay]

Re: Acer Aspire 5750 no B+ voltage

Measures PQ19 taken according to this numbering?
See Annex
Voltages do not add up
Considering the numbering as an attachment
PQ19 pin 1 connected to pin 23 of PU1 (0V correctly stated)
pin3 PQ19 (must essera to about 3V) connected to pins 2, 5 PQ14 (0V incorrectly stated)
Pin 2 to ground PQ19
Check that the pin 2 of 3 PQ19 are not short.

i've checked PQ19 but only 1 pin is shorted to groun other pins are not shorted