Lenovo G50-80 Not ON Charger (no led) but Battery OK (ACLU3/ACLU4 UMA NM-A362)

[zakiyy]

Hello,
Lenovo G50-80 (ACLU3/ACLU4 UMA NM-A362) Rev 1.0
With battery laptop work perfectly ! But with charger no power and not charging ! What can be the problem??

Direct from Charger PIN no connect to laptop: 20.v

PQ301 (4407A)
Drain: 20v - 19v 17v fluctuating
source: 19v - 18 -16v fluctuating
Gain: 19v - 18 -16v fluctuating

PQ302(4483a)
Drain: 2.5v then 5 then 10v then 11v sometimes18 then again 2.5v again and again..
source: 19v - 18 -16v fluctuating
Gain: 19v - 18 -16v fluctuating

[zakiyy]

Re: Lenovo G50-80 Not ON Charger (no led) but Battery OK (ACLU3/ACLU4 UMA NM-A362)

When remove PQ302(4483a)
Drain pin - 0.886 stable
Source PIN: 20v stable
Gain pin: 5.05v Stable

PQ301 (4407A)
Drain: 20v
source: 20v
Gain: 5v stable

When do Jumper the laptop does not power on !

[lapfix]

Re: Lenovo G50-80 Not ON Charger (no led) but Battery OK (ACLU3/ACLU4 UMA NM-A362)

Start with usual steps .With no power try :
Diode mode : measure PQ 301/302
Diode mode at PR301 and at all coils to confirm if there's or no a short !.
If no short to ground proceed to take voltages of PU301 :
Pin 20/6/5/16

UE1 :
pin 72 = ADAPTER_ID voltae !

[Sametbey]

Re: Lenovo G50-80 Not ON Charger (no led) but Battery OK (ACLU3/ACLU4 UMA NM-A362)

According to your voltage measurements, your PU301 and inlet mosfets are intact. Possible short circuit at the + B point at the exit or after. You can start check to PU904 or PU905 + 3v.

[zakiyy]

Re: Lenovo G50-80 Not ON Charger (no led) but Battery OK (ACLU3/ACLU4 UMA NM-A362)

Diode mode : measure PQ 301/302 - NO SHORT
Diode mode at PR301 and at all coils to confirm if there's or no a short !. - NO SHORT
If no short to ground proceed to take voltages of PU301 :
Pin
20: 20v
6:2.5v
5: ov
16: 5.95v

UE1 :
pin 72 = ADAPTER_ID = 0v

PLEASE NOTE
is remove PQ302(4483a)

[zakiyy]

Re: Lenovo G50-80 Not ON Charger (no led) but Battery OK (ACLU3/ACLU4 UMA NM-A362)

PU904 Short

PL 303 SHORT.. even remove it still short on the PIN.. where can i find the fault !

[Sametbey]

Re: Lenovo G50-80 Not ON Charger (no led) but Battery OK (ACLU3/ACLU4 UMA NM-A362)

You can remove the PU904 and determine which foot has a short circuit. ITE IO can short circuit over power jack from hinge fault. You can detect the heated part by giving the PJ303 a voltage starting from 1V. or PU904 from 5 pins

[salawayon]

Re: Lenovo G50-80 Not ON Charger (no led) but Battery OK (ACLU3/ACLU4 UMA NM-A362)

I got a dead NM-A361 board and no short circuit on it. with ff details so far,

LENOVO G50-80_DISCRETE_NM-A361
= PQ301_4407A
PIN5678 = 19.7V
PIN123 = 19.7V
PIN4 = 19.52V

= PQ302_4483A
PIN5678 = 0.89V ***?
PIN123 = 19.7V
PIN4 = 19.52V

= PU301_BQ737
PIN5 = 0V
PIN6 = 2.59V
PIN16 = 6V
PIN20 = 19.7V

= UE1_IT8586E
PIN72 = 0V

tried already replacing the ff:
= PQ302 twice
= PU301
= UE1

[mcplslg123]

Re: Lenovo G50-80 Not ON Charger (no led) but Battery OK (ACLU3/ACLU4 UMA NM-A362)

PQ307,PIN5 Voltage?? Remove PQ304 & PQ305 and measure PQ301,pin4 voltage. Why un-necessarily change so many components??

[salawayon]

Re: Lenovo G50-80 Not ON Charger (no led) but Battery OK (ACLU3/ACLU4 UMA NM-A362)

PQ307,PIN5 Voltage?? Remove PQ304 & PQ305 and measure PQ301,pin4 voltage. Why un-necessarily change so many components??

= PQ307_K27
PIN1 = 0V
PIN2 = 3.28V
PIN3 = 0V
PIN4 = 0V
PIN5 = 3.28V
PIN6 = 0V
= PQ301_PIN4 = 19.52v without PQ304 and PQ305

[mcplslg123]

Re: Lenovo G50-80 Not ON Charger (no led) but Battery OK (ACLU3/ACLU4 UMA NM-A362)

PQ307 is working fine and so your voltage divider for PQ301 gate should've wokred but somehow not working. Remove PR303/307 and check resistance out of circuit. Do they match schematic values?? PQ301 is not shorted??

[salawayon]

Re: Lenovo G50-80 Not ON Charger (no led) but Battery OK (ACLU3/ACLU4 UMA NM-A362)

PQ307 is working fine and so your voltage divider for PQ301 gate should've wokred but somehow not working. Remove PR303/307 and check resistance out of circuit. Do they match schematic values?? PQ301 is not shorted??

* PQ301_AO4407A = had a very low resistance reading between DRAIN and SOURCE pins, just 26ohms only. had it replaced but still the same status (dead unit)
* PR303/PR307 = had it removed and values were the same with the schematics... after putting back both resistors with hotair, PQ302 pin5678 gives an output of 19.7v but after cleaning the flux it went back to 0.89v. so, i decided to reflow all resistors near PQ307 and PU301 and by luck it's now alive... but i noticed another problem, it shutdown after a few seconds after power ON when battery and charger were both attached. but sometimes it works normal with both battery and charger attached but it won't charged the battery. after using another charger a smell of burning component came out from the laptop. one AO4466 mosfet near the battery terminal got busted. unit is now in normal status after replacing the AO4466 mosfet.

thank you very much for your tutorials and time...

[mcplslg123]

Re: Lenovo G50-80 Not ON Charger (no led) but Battery OK (ACLU3/ACLU4 UMA NM-A362)

@salawayon, great to know you fixed it but keep your fingers crossed. Since it worked after applying heat it may begenuine cold solder but it can be a bad resistor/cap/ic nearby. So just observe the unit for next 7 days. If it survives a week or so, hopefully its fully fixed.

[Bartoloni]

Re: Lenovo G50-80 Not ON Charger (no led) but Battery OK (ACLU3/ACLU4 UMA NM-A362)

i received today another laptop like this one.. with PU904 becoming Hot... the EC seems fine, not shorts on nearby capacitors and no short on center pin of power connector, injecting on pin 5 of the PU904 the CX20752 (digital audio amplifier) starts heating, can be nice to remove the audio IC ... but customer wan't pay for a motherboard repair