Acer E1-571G No Power

[boyebaran]

Hi
please advice me about this problem.e1-571g no power
i have not 3alwp and 5alwp.
RT8205 and bq24725 replaced.KB9012 reprogrammed and not change.
which point need to check?please help me.
tnx

[smali]

Re: Acer E1-571G No Power

first check Adopter 19v DC or Battery voltage on +B line...if OK then check +3VLP and 5VL on RT8205 PIN#8 and 17 then check 3v volt on switch and post the status.

[boyebaran]

Re: Acer E1-571G No Power

tnx
19 v is ok.3&5 vl is ok too.3.3 volt is ok on switch

[boyebaran]

Re: Acer E1-571G No Power

PQ21:
pin1 = 3.3v
pin2 = 0v
pin3 = 0v

PQ21
pin3 & 6 = 1.71v
the pin 2 & 5 = 0V
the pin 1 & 4 = the GND

PU5
pin1 = 1.71
pin3 = 1.98
pin6 = 1.71
pin8 = 3.3
pin9 = 5v
pin13 = 3.7v
pin16 = 19v
pin17 = 5
pin22 = 5

[smali]

Re: Acer E1-571G No Power

OK..just for checking remove PQ20 double FET and check always volts if not.
Then short to ground PIN 6 and 3 ( drain) of PQ20 and check the 3 and 5 always on coil and post the status.

[boyebaran]

Re: Acer E1-571G No Power

tnx smali
shorted pin 6 to Gnd and 5 volt coming.but if i shorted pin 3 to gnd than not only 3.3 volt is not ok but also 5 volt gone to zero.
i tested PL6 and PL7 ohm to gnd and PL6 have 800 ohm to gnd.i think 3.3 line have a problem

[smali]

Re: Acer E1-571G No Power

PQ21:
pin1 = 3.3v
pin2 = 0v
pin3 = 0v

PQ20
pin3 & 6 = 1.71v
the pin 2 & 5 = 0V
the pin 1 & 4 = the GND

OK check short on both coils but you are missing something if PQ21 pin1 (collector) has 3.3v then PQ20 pin2&5 has definitely 3.3 voltage because both are directly connected but i think you count pin wrongly please confirm.

[boyebaran]

Re: Acer E1-571G No Power

sorry my mistake pin1 pq21 is zero.pin2 have 3.3 volt

[boyebaran]

Re: Acer E1-571G No Power

pin2 of pr79 have 5v but pin1 is zero

[smali]

Re: Acer E1-571G No Power

yes pr79 0v poit is connected to transistor collector and that transistor pulled to ground.
ok install pq20 and remove only only pq21 transistor and check.

[boyebaran]

Re: Acer E1-571G No Power

after removing pq21 the pin1 is about 4.7 volt and pin 2 is 3.3v

[smali]

Re: Acer E1-571G No Power

now check voltage on coils 3&5

[smali]

Re: Acer E1-571G No Power

remove the transister and check 5 and 3 volts on coil

[smali]

Re: Acer E1-571G No Power

install pq20 and remove pq21 and check 5 and 3 volts on coils

[boyebaran]

Re: Acer E1-571G No Power

pl 3&5 is 19 volt . without pq21` no voltage 3.3&5 v in coil

[boyebaran]

Re: Acer E1-571G No Power

my friend i have seem working motherboard and if u need measuring some voltage in ok motherboard please tell me.
thank you very much for your time

[smali]

Re: Acer E1-571G No Power

PL5 and pl3 are +b voltage thats ok. are u installed pq20 and removed pq21?
how many ohms to ground of pl6 and pl7?

[boyebaran]

Re: Acer E1-571G No Power

OK check short on both coils but you are missing something if PQ21 pin1 (collector) has 3.3v then PQ20 pin2&5 has definitely 3.3 voltage because both are directly connected but i think you count pin wrongly please confirm.

i connected external 3.3 v to the coil(pl6) for short test and every things is normal(no Warm up any part )

[smali]

Re: Acer E1-571G No Power

also check the FETs pq16 and pq18 if you spears that FETs try to replace.

[boyebaran]

Re: Acer E1-571G No Power

PL5 and pl3 are +b voltage thats ok. are u installed pq20 and removed pq21?
how many ohms to ground of pl6 and pl7?

pl6 to gnd is about 800 ohm
pl7 to gnd about 13 kohm
in normal motherboard pl6 to gnd is about 5 k ohm