Re: Troubleshooting: Lenovo Motherboard
that very low value for +1,35v line , check pq501 and pq502
that very low value for +1,35v line , check pq501 and pq502
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Re: Troubleshooting: Lenovo Motherboard
I have a hard time testing these mosfets
Resistance measurement keeps increasing forever or keeps decreasing forever or else it just changes value like crazy (since I have it set on auto range, sometimes it even switches between kohms and mohms). Can't understand why this happens. Maybe I'm just doing something wrong.
I am just trying to follow this. Is this the correct way or am I getting crazy?
1. Black on Source and Red on Drain
2. Red to Gate momentarily
3. Black on Source and Red on Drain
EDIT: Probably red should be on source (checked the diode symbol here)
In the meantime I've measured the voltage:
PQ501:
D > 19V
S > 0V
PQ502:
D > 0V
S > 0VLast edited by DanFen; 03-18-2020, 10:25 AM.Comment
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Re: Troubleshooting: Lenovo Motherboard
when power on check +3VALW_SOC (Q26 pin1 -Drain) +1.0VALW (PJ702) +1.8VALW (pj602) VR_+1.0VALW_PWRGD (pin 5 of PU701 )
and SYSON signal on PU501 pin 16 (S5)
with simplicity :
N-channel : (diode mode)
1-red (source),black(drain) 0500~0600
2-black(source),red(drain) Open
3-and test if source and gate short together or not
P-channel : (diode mode)
1-red (drain),black(source) 0500~0600
2-black(drain),red(source) Open
3-and test if source and gate short together or notLast edited by kiraro; 03-18-2020, 01:49 PM.Comment
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Re: Troubleshooting: Lenovo Motherboard
Thanks for the clarification
+3VALW_SOC (Q26 pin 1 - Drain) = 3.3V
+1.0VALW (PJ702) = 1V
+1.8VALW (PJ602) = 1.8V
VR+1.0VALW_PWRGD (PU701 pin 5) = 3.3V
SYSON signal on PU501 pin 16 (S5) = 0V
PQ501 (n):
Source (red) to Drain (black) = 0.554
Source (black) to Drain (red) = 2.9
no cont between gate and source
PQ502 (n):
Source (red) to Drain (black) = 0.08
Source (black) to Drain (red) = 0.370
no cont between gate and source
Last edited by DanFen; 03-18-2020, 03:11 PM.Comment
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Re: Troubleshooting: Lenovo Motherboard
check pj201 +20VSB (pin1 PQ210)Comment
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Re: Troubleshooting: Lenovo Motherboard
Syson and susp# are the enable signals for PU501.
Syson enable Pu501 to generated 1.35V. Susp#enable Pu501 to generated 0.675V.
In the power sequence , before this steps (suson and susp#) we have to check PM_SLP_S3# and PM_SLP_S4# at UE1 pin 18 and 21.Comment
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Re: Troubleshooting: Lenovo Motherboard
- UE1 Pin93 EC_RSMRST#
-all pins voltage QC11 and QC12Last edited by kiraro; 03-20-2020, 05:22 AM.Comment
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Re: Troubleshooting: Lenovo Motherboard
It seems that your S3 state won't be complete ,did PU501 get hot ! try to use a good known ram (DDRL)
What's the voltage on pin 12 !
Try to flash your bios .Comment
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Re: Troubleshooting: Lenovo Motherboard
In such case, since it's not a high end motherboard, I think it makes more sense to simply order another one.
Just want to thank all of you guys who supported me with this, I definitely learnt some new stuff
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Friends. I beg you to help me in this situation.
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Hello,
I need your help with an issue I'm encountering while diagnosing a NM-D471 REV 2.0 motherboard from a Lenovo laptop. The laptop won’t power on. I started by checking the power rails, including the main power line and the 3.3V and 5V rails.
I do have a proper 3.3V across the line, including at the chip responsible for managing 3.3V/5V—same goes for the 5V rail. I haven’t tried to simulate a power-on yet, since the main issue still needs to be resolved.
I have full access to the boardview, but I’m not sure what to check next to isolate the problem.
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