Lenovo G50-80 Turns on and off within 4-5 seconds

[mcplslg123]

Model :Lenovo G50-80
M/b: NM-A361 Rev 1.0
Problem: Can turn on with power switch but turns off within 4-5 seconds, No display.

Observation:
1. No liquid spill or corrosion observed.
2. 3v/5v alw present.
3. All voltge rail rises for 3-4 seconds when turned on ,then laptop turns off.
4. NO coil is shorted to Ground.

I have replaced PU1207(TPS51716),still same.
I have flashed both EC & Main with various dumps,still same.

Following signals are present:
SYS_POWEROK
SUS_VCCP
PBTN_OUT#
PM_SLP_SUS#
pch_PRW_EN
PCH_PWROK
LID_SW
PM_SLP_S3#
PM_SLP_S4#

MAINON Signal is missing at pin 79 of IT8586E.

Any ideas friends

[mcplslg123]

Re: Lenovo G50-80 Turns on and off within 4-5 seconds

EC_ON PRESENT
EC_LID OUT PRESENT
EC_VR ON-MISSING
DPWROK-PRESENT
EC_RSMRST-PRESENT
PLT_RST-PRESENT
VCC-PRESENT
AVCC-PRESENT
SYS_ON-PRESENT.

So Far i have observed two signals missing from kbc- MAINON(PIN79) & EC_VR ON(PIN 125)

I could'nt find NM-A361 Rev 1.0 Schematics. Attaching NM-A362 schematics which is very close match.

[meritosari]

Re: Lenovo G50-80 Turns on and off within 4-5 seconds

Try to lift Codec_CX20752, maybe was broken audio controller

[meritosari]

Re: Lenovo G50-80 Turns on and off within 4-5 seconds

Btw, pin 79 wasn't mainon. Its MAINPWON. For S3- S0 signal need syson and susp#

[mcplslg123]

Re: Lenovo G50-80 Turns on and off within 4-5 seconds

Thanks meritosari for your response. I have already lifted audio/lan codec,still same. Yeh pin 79 is mainpwon, typing mistake. Syson and susp# appears when switching.

[smali]

Re: Lenovo G50-80 Turns on and off within 4-5 seconds

Are you checked Q23&Q24 (3vs&5vs) source side with ground short circuit how many ohms showing multimeter?

[mcplslg123]

Re: Lenovo G50-80 Turns on and off within 4-5 seconds

Are you checked Q23&Q24 (3vs&5vs) source side with ground short circuit how many ohms showing multimeter?

Q23 & Q24 is not shorted. Showing 570 in diode mode(black probe on gnd) for pin 1/2/3/5/6/7/8 and infinity on pin 4. I'm getting 3v and 5v on pin 1-2-3 and 19v on pin 4. Pin5-8 also showing 3v and 5v. So i dont think 3 and 5v VS line is shorted.

[mielta]

Re: Lenovo G50-80 Turns on and off within 4-5 seconds

Hi
check Powerbutton for contact resistance

[smali]

Re: Lenovo G50-80 Turns on and off within 4-5 seconds

Q23 & Q24 is not shorted. Showing 570 in diode mode(black probe on gnd) for pin 1/2/3/5/6/7/8 and infinity on pin 4. I'm getting 3v and 5v on pin 1-2-3 and 19v on pin 4. Pin5-8 also showing 3v and 5v. So i dont think 3 and 5v VS line is shorted.

OK..check LCD connector area specially LCD VDD filter capacitor (C7,C8,C43) or check Q9 drain L1 with ground may be when PCH enabling LCD VDD and if said capacitors short then your 3vs have a chance to drop otherwise you CPU ( processor) may be faulty.

[mcplslg123]

Re: Lenovo G50-80 Turns on and off within 4-5 seconds

LCD VDD filter capacitor are all ok. Q9 (all three pins) not shorted to ground.If it is processor----hmmm.....

[mcplslg123]

Re: Lenovo G50-80 Turns on and off within 4-5 seconds

Hi
check Powerbutton for contact resistance

checked, not shorted nor near continuity to GND.

[mielta]

Re: Lenovo G50-80 Turns on and off within 4-5 seconds

i woud check page52 PU201 circuit i think when it not ok
he says temp to high and than shut down
Mainpwon signal

[caspian]

Re: Lenovo G50-80 Turns on and off within 4-5 seconds

are the four GPU voltage rails are present?
how much voltage on pin1 of PU908?

[mcplslg123]

Re: Lenovo G50-80 Turns on and off within 4-5 seconds

i woud check page52 PU201 circuit i think when it not ok
he says temp to high and than shut down
Mainpwon signal

I too doubted it but PU201 is not populated on this mb.

[mcplslg123]

Re: Lenovo G50-80 Turns on and off within 4-5 seconds

are the four GPU voltage rails are present?
how much voltage on pin1 of PU908?

I have already mentioned that two signals are missing from sio-mainpwon and ec_vr on. Without Ec_Vr on there cannot be any voltage on pin1 of PU908.. However, i injected 5v on pin 20 of pu908 from 5v coil, switched mb and got core voltage on coils. So i think nothing wrong in PU908. I replaced it also from HP Y11 mb, still no luck.

[smali]

Re: Lenovo G50-80 Turns on and off within 4-5 seconds

I have already mentioned that two signals are missing from sio-mainpwon and ec_vr on. Without Ec_Vr on there cannot be any voltage on pin1 of PU908.. However, i injected 5v on pin 20 of pu908 from 5v coil, switched mb and got core voltage on coils. So i think nothing wrong in PU908. I replaced it also from HP Y11 mb, still no luck.

I am confused with your statement as highlighted why you injected 5v on pu908 pin 20 because there is already present 5valw through PR9346( 0 ohm) is this resistor ok

[mcplslg123]

Re: Lenovo G50-80 Turns on and off within 4-5 seconds

PR9346 was ok but still was not getting 5v at pin 20, so injected just to test the IC.

Anyway, friends thanks for your support and time. customer was i hurry and took away the laptop unrepaired. So we can treat this thread as closed.

[Wilbert61b]

Re: Lenovo G50-80 Turns on and off within 4-5 seconds

Hi mcplslg123 and Smali,

I've got a simular problem. I have a lenovo G50-80 laptop with ACLU3/ACLU4 UMA NM-A362 rev.1.0 mobo. Whenever I plug on the power the power led starts burning for 4-5 seconds, fan and harddrive make a few turns but then everything dies. Tried al kind of stuf I found on the internet but nothing. So I opened it up. No water damage etc etc. Battery chargers works ok! I have taken the mobo out and I am testing it without ram, wifi, hdd etc etc. Just the mobo and power line. I Have read everything you to wrote and understand almost everything accept the part about all the signals and about lifting the codec (always thought that is software). Don't know how to check that. I Have taken the scheme you posted altough it is a rev4 mobo.I have checked PO 202 and PO 301. Both work fine. 20v on the drain and source and 5v on the gate. next I have checked Q23 and Q24. 5volt and 3Volt on pens 8-7-6-5, 0 volt on pen 4 and 0 volt on pen 1-2-3. Q25 gives me 0volt on all three points Q26, Q27, Q28 are printed on the board but not occupied (is that correct English). In the scheme I see at the gate of Q26 in red SUSP. I cant find the resistors on the motherboard. (R148,R149,R153 R147, R151, R152).

Now I have a few Questions. Hope you can help me out.
* Is there somewhere a component layout so I can find the parts?
* Is the SUSP marking in the scheme a signal coming from somewhere else and what does it?
* What do the abbreviations ALW (5valw) and S (5vs) stand for?
* Any suggestions where to look now?

Thanks!

Wilbert

[piernov]

Re: Lenovo G50-80 Turns on and off within 4-5 seconds

* Is there somewhere a component layout so I can find the parts?

I think you're looking for a boardview, but it seems not to be available for this motherboard.

* Is the SUSP marking in the scheme a signal coming from somewhere else and what does it?

SUSP is created from SUSP#, it is the same signal but inverted by Q6A. SUSP# comes from the EC, and it turns on the regulators for +5VS, +3VS, +1.5VS and +0.675VS.

* What do the abbreviations ALW (5valw) and S (5vs) stand for?

VALW are power rails that are always present. In fact, they're usually not present when the computer is off and the AC adapter is not connected, but they are present when the computer is off and the AC adapter is connected.
VS are power rails that are present when the computer is on, I guess S stands for suspend but in fact they are not present in suspend S3 mode, only in S1 and S0.
You can see that on the power state table on page 3.

* Any suggestions where to look now?

Check on page 47 the power sequence, and check which signal is missing. You know that you're missing SUSP# at step 9 so you can go backwards from there.

[Wilbert61b]

Re: Lenovo G50-80 Turns on and off within 4-5 seconds

Dear Pearnov,

Thanks for the reply. Just been reading and measuring. I get the following:

1. DPWROK_EC pin 35 --> 3.3 volt
2. PCH_PWR_EN# pin 97 --> 3.3 volt
3. + 3V_PCH couldn't find this one. Q25 has 5 volt on the source and 0 on gate and drain. according to the scheme that is correct because it switches 5VALW to 5VS. So I guess I am missing something here
4. PCH_RSMRST# couldn't find this one. Read page 44 again and again, blow it up to 200% but I guess my eyes are getting old ;-)
5. PBTN_OUT# pin 86 --> 3.3 volt
6. PM_SLP_S3# pin 18 --> 0 volt
PM_SLP_S4# pin 21 --> 0 volt
PM_SLP_S5# pin 106 --> 3.3 volt
PM_SLP_SUS# pin 87 --> 3.3 volt
7. SYSON pin 107 --> 3.3 volt
8. SUS_VCCP pin 34 --> 3.3 volt
9. SUSP# pin 124 --> 0 volt

I have been looking to find the PCH. Maybe I am to much a newbe at this stuff. I understand (google) it is the Platform Controller Hub and it it handels the signals to the hardware like display, sound etc. What ic is this here and on what page did I miss it.

Thanks again for answering and teaching me!

Wilbert