I have a Lenovo G40-45 (nm-a281p) motherboad which is dead. I measure there is only 0.9v in B+ while the Vin is 20v
Please help, where to start troubleshoot the problem, thanks.
Please help, where to start troubleshoot the problem, thanks.
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Re: Lenovo G40-45 Dead, low voltage on B+ Need help
Check charging pin -
Re: Lenovo G40-45 Dead, low voltage on B+ Need help
Check voltage sensing on PR and mosfet from dc port..Comment
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Re: Lenovo G40-45 Dead, low voltage on B+ Need help
And i read from the power sequence, that B+ created from PU401. But there is no PU401 in the schematic that I can find.
So, what created B+, or which component that created B+Comment
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Re: Lenovo G40-45 Dead, low voltage on B+ Need help
And weird thing I just noticed, even after i remove the charger, there is still voltage on B+ for a while and it is dropping from 0.9v to 0v very slowly.Comment
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Re: Lenovo G40-45 Dead, low voltage on B+ Need help
Try replace PQ7, I have got same problem with similar lenovo and this worked in my case.
"B+" is created from "VIN" through PQ6 and PQ7. PU401 uses it to power itself.Comment
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Hi,
my Lenovo 720 is dead. :-(
I guess i have found an issue on the 5V buck converter (**BAC7NH** from Silergy (also called SY8288C 5V)) but i am not completely sure so i want to ask here for some hints.
Here is a Schematic of the IC: https://prom.ua/p1498216381-sy8288c-...ac-bacxxx.html
When i attach the supply 19V, i only have 1.8V on the OUT (it should be 5V). The IC is getting hot.
The EN1 is completely off 0V, EN2 show 1.5V.
If i inject 5V on the EN1 the OUT goes up to 2.6V (but never reach 5V).
BS seams SHORT to the OUT.... -
This is my first attempt at troubleshooting a board like this, I know I could just buy a new board but I'm curious to figure out how this works. I've been testing different components in the evenings this week and I think the problem is with the IC failing to start up for some reason. When the board is plugged in there is no standby voltage.
Then today it randomly sprung to life like a zombie but shortly died thereafter. I have no idea why it would have done that and its the first time I've seen it running. I discharged capacitors on the board last night, then it was sitting today.... -
First of all, ive veen reading these forums for some time and its always veen very helpful, so i thank you all for this amazing comunity.
I have a lmq-2 13268-1 motherboard from a lenovo x1 carbon 3rd gen. And the MX25l12873f (U49) bios pin 8 is not getting voltage.
So far these are my diagnostics:
When given 19v trough power adapter, consumption reads 0.003 amps for about 5 seconds then nothing.
When power button pressed same result, and i get three green blinking lights from the pwr btn led. But foesnt turn on.
If i plug the battery... -
Hi everyone, I replaced this motherboard because it was important to get it working, but it's been with me for a very long time. Now I finally have time to figure out what the problem is,
I've never encountered something like this before;
No charging light, full dead
Lenovo Ideapad 330-17ICH- PL3102: 5 ohms
- PL3001: 3.2 ohms
- PL3101: 2 ohms
- PL5801: 3.5 ohms
- PL5501: 270 ohms
- PL701: 35 ohms
- PL501: 146 ohms
- PL503: 390 ohms
- PL402: OL (0.27V) +5VALW_P
- PL301: OL
- PL401: OL (0.03V) +3VALW_P
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Hi all,
I have a Lenovo Yoga 13 Panasonic here, when powered- both fans spins (the sconds starts with a bit of a delay), no image neither on HDMI nor the display
- most voltage rails seem OK (see image below, red labels)
- resistnace to ground mostly seem OK as well (blue labels)
- the resistance to ground is rather low (1.9ohm)
- when injecting the voltage (1V), it consumes around 200mA, seems OK to me (?)
I can't find a schematics for the board - can some of you gurus look at the voltages?...
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