Lenovo g475 shuts off in 3minutes

[String2016]

Hi everyone I need help and advise i have lenovo g475 la-6775p laptop turns on after 3minutes shuts off.boots fine but after 3minutes shuts off.anyone please help thanks in advance

[String2016]

Re: Lenovo g475 shuts off in 3minutes

I need help please laptop turns on but after 3minutes shuts off and then when i turn it back again it turns on then a minute shuts off again and again.please

[String2016]

Re: Lenovo g475 shuts off in 3minutes

And also when i plugged in the battery there is no battery indicator and cannot charge

[subroto]

Re: Lenovo g475 shuts off in 3minutes

Possible problem-

i)Graphics chip(if has)
ii)BIOS
iii)CPU core voltage
iv)Main power Vin section(along with charge controller and MOSFET)

At first start with BIOS.

[dspok]

Re: Lenovo g475 shuts off in 3minutes

This is thermal related issue not thermal IC, last time I faced this problem with dell 4030. Everytime you start machine it will remain for less time e.g 1st time it stays for 3mins, later for 2mins, and later 1min, last it will start for few seconds.

[String2016]

Re: Lenovo g475 shuts off in 3minutes

Thanks for the response i think this is not thermal issue because i already done replace thermal paste at cpu.it just starts happens when custumer use wrong charger.what should i do should i reflashed first the bios?please advise and help please

[String2016]

Re: Lenovo g475 shuts off in 3minutes

I measured PQ301 pin 2 to 4 all 19volts and 5 to 8 are 0volts and also i measurex a PU101 pin 1 to 5 are 0.25 volts and pin 6 2.45 vols and 7 0volts and 8 19 volts.i have attached the image

[subroto]

Re: Lenovo g475 shuts off in 3minutes

Do you have schematic bro? Then chrck short or leackage capacitor in DC_Batout or Vin(I don't no exactly the signal name for this mobo) section. Ensure output voltage 18.5-19v. Then go through BIOS.

[String2016]

Re: Lenovo g475 shuts off in 3minutes

thanks for the response i will check the short capacitor on dc battout I have attached bro subroto the schematic thanks

[String2016]

Re: Lenovo g475 shuts off in 3minutes

I measured the capacitor around dc batt c956 polymer capacitor there is no voltage check also PL101 fluctuating voltage and PL201 no voltage. anyone please help before laptop when plugged in charger led light showing and also battery charging but now when I plugged in the charger there is no led light and also if i connect the battery no charging light. laptop turn on then after 3minutes shuts off anyone please help

[subroto]

Re: Lenovo g475 shuts off in 3minutes

measure the gate voltage of of PQ301 I mean pin nmber 4 of both PQ301 and PQ302. The gates of the two MOSFET is the same. If it's 0v then check PACIN signal at PR318 and also the gate og PQ308B.
Most probably B+ and CHG_B+ are not generated in your unit. trace them.

[String2016]

Re: Lenovo g475 shuts off in 3minutes

I measured gate pin 4 of pq301 its 19 v and i cannot find pq302 i found only pq303 and measured pin 4 is 0volts.

[String2016]

Re: Lenovo g475 shuts off in 3minutes

I have attched the image of the board

[String2016]

Re: Lenovo g475 shuts off in 3minutes

Anyone please help on this

[subroto]

Re: Lenovo g475 shuts off in 3minutes

According to your schematic of page 38, check the source voltage of PQ301(P2 point voltage) and check the gate voltage of PQ302. If here is no voltage, then short the two gate of PQ301 and PQ302. You will find B+ voltage perfectly.

[subroto]

Re: Lenovo g475 shuts off in 3minutes

This is PQ302 in your pic.

[String2016]

Re: Lenovo g475 shuts off in 3minutes

Thanks for the response bro subroto i done checked both pin 4 gate of pq301 and pq302 its 19.9 volts both and checked also as you mentioned pin 2 source of pq301 its also 19.9 volts.should i short the pin2 of pq301 and pin4 of pq302?please help thanks

[String2016]

Re: Lenovo g475 shuts off in 3minutes

anyone please help

[String2016]

Re: Lenovo g475 shuts off in 3minutes

please help

[subroto]

Re: Lenovo g475 shuts off in 3minutes

How much voltage at P3 point?