Re: Lenovo N500 - No power
when i remove PQ5 same thing happen, voltages still osctilates
when i remove PQ5 same thing happen, voltages still osctilates
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...the quieter you become the more you are able to hear... -
Re: Lenovo N500 - No power
i try to remove PQ19 and now i have 0V on that rail that i have earlier oscilating voltages...the quieter you become the more you are able to hear...Comment
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Re: Lenovo N500 - No power
That's pretty peculiar. B+ is connected to PU10, and since removing PL12 stops the oscillation, and since removing PQ5 does not stop the oscillation, that suggests that any component between PL12 and PQ5 could be bad. So PC39, PC38, PC37, PC36, PC150, PR17, PC13, PC8, PC1, maybe even PU1 itself.
Or whatever the hell is connected to CHG_B+.
Again, I could be wrong! I'm no professional at this. It might be worth checking PQ32 and PQ34
EDIT: If it did work on battery PQ32 and PQ34 would be okay, actually. Which would also mean B+ is fine and it's something charger-related (I suppose CHG_B+ could still be at fault)Last edited by spleenharvester; 03-10-2014, 05:50 PM.Dell E7450 | i5-5300U | 16GB DDR3 | 256GB SSDComment
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Re: Lenovo N500 - No power
Just took another look, this isn't making much sense to me. Presumably, voltage would be flowing through those components while on battery anyway? And if it was indeed working on battery, this suggests the problem is elsewhere?Dell E7450 | i5-5300U | 16GB DDR3 | 256GB SSDComment
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Re: Lenovo N500 - No power
i found the problem, it was solder bridge on PQ19, now i have 17V on that rail, and 3V on BIOS...the quieter you become the more you are able to hear...Comment
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Re: Lenovo N500 - No power
uhh i will go crazy with this one, i have 16.9 and 17.10 oscilating voltage on that rail. Laptop still wont start...the quieter you become the more you are able to hear...Comment
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Re: Lenovo N500 - No power
there is a possible leaky capacitor or fet along the 19v rail. you should use your bench power supply to isolate it.Comment
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Re: Lenovo N500 - No power
Such a small variation should not interfere with startup. The b+ rail can be from 19v to battery voltage. But it indicates that something is wrong. On pg 46, the oscillation is at pq38 drain only or source also? +5alw and +3v exist and are stable?Comment
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Re: Lenovo N500 - No power
this is crazy i check now and i have stable 14.8V on drain of PQ38. Source is 19V.
On PU10 3V output is 0V and 5v output is oscilating 0-4v...the quieter you become the more you are able to hear...Comment
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Re: Lenovo N500 - No power
ahh now again oscilating voltage at PQ38...the quieter you become the more you are able to hear...Comment
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Re: Lenovo N500 - No power
have you ever tried to clean up these area? . insect pee sometimes leave no traceComment
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Vizio e601i-A3 - Has Sound and Display, But No Backlight - Bad Power Supply Board or Bad LED Bulbs ?I was given this TV from my great uncle. He said it just wouldn't turn on one day out of nowhere, replaced the TV, and gave it to me to possibly fix and use for myself.
Upon bringing it home and plugging it up, it showed a standby light.
I powered it on and without a flashlight, the display showed the "V" but the lighting is very dim, but visible.
The screen seems to blackout and stay black, but with a flashlight I can see the display.
With my Playstation 4 connected via HDMI, and running a game I can hear sound.
Assuming... -
Hi all!
I'm trying to troubleshoot a Microsoft Surface Pro (5th gen) model 1796 that won't power on. Motherboard model is M1007506-015. My priority is retrieving data, but the SSD is integrated so it looks like if I can't repair it it'll need to go to a data recovery company. I've done a little basic board repair before, but nothing this advanced until now. So please forgive my ignorance in advance. 😅
I found the boardview for this laptop in the forums here, and am able to open it on my PC with FlexBV.
https://www.badcaps.net/forum/troubl...-hardware-devi... -
Hi all,
TL;DR - this laptop is driving me nuts with the oddball power-related behaviors. Appreciate any insight you can provide!
I'm experiencing a power issue on an Asus Probook P5440UF-XB74. Although I've worked with electronics and computers for decades, this is my first attempt at getting into motherboard-level component troubleshooting. Any help the community can provide is greatly appreciated!
A few weeks ago I was using the laptop (on battery power) for a Zoom meeting. The battery was running very low (long meeting) but I wasn't worried about... -
Hi,
Try to repair a Thinkpad P72 EP720 NM-B723 MB with I7-8850H processor and N18E-Q1-KB-A1 (P3200) GPU with 6GB memory. Unfortunately there is noinfo what happened to the laptop. I got it disassembled with parts missing, like keyboard, battery.
Unfortunately I have no schematic available for me (requested in the sub porum) but got the boardview file.
Symptom: after connecting to the charger the power led light up for one-two second and switch off. After a couple secons the power led light up for half a second and switch off. No battery, no IO board, no... -
I have a lenovo ideapad 5 14itl05, board LA-K321P, That will only power up on Battery only, or with battery disconnected and power adapter only. If battery is connected and usb-c power plug connected. It only works on battery and will not charge. I can however force it to charge by connecting the battery from a disconnected state while the power USB c plug is powering the laptop.
Additionally....to add to this strange situation. The usb-c power plug ONLY works to power the laptop on one side when inserted into the boards power usb c plug. If you rotate it 180 degrees, the board gets...
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