kjchatman
Badcaps Veteran
Last Activity: Yesterday, 11:25 AM
Joined: 12-28-2012
Location: spring lake/ north carolina
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reattaching the PCH to the dell la-k452p
i've done a lot of smaller bga chip replacments but the pch attachment on this board is proving to be nearly impossible without better equipment. does anyone have tips on getting good alignment of the chip? i've reattached it a few times and always end up with at least one shorted power rail -
la-k452p dell m15 r6 board won't power up but power light occasionally glows and flashes
when it's plugged in the PCH glows under the thermal camera and the battery charges. the coil PLG1 for +vccin_aux reads 1.8vLast edited by kjchatman; 09-09-2025, 08:27 PM. -
apple configurator restore did the trick -
820-01700 motherboard charges but does nothing else
2019 16" macbook pro that came to me for a diagnostic. it charged the battery up without a problem but doesn't power up. and with the battery detached it will show 20v and 0 amps on a usb-c amp meter. i went around the board looking for a short but found nothing obvious -
i'm sure the cpu is the problem because the capacitors on the cpu for that power rail are shorted....Leave a comment:
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do you think i can swap that ryzen 7 5800h with a 5800u. That's the only spare cpu i've gotLeave a comment:
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i ended up removing the cpu after removing PQA1 AND PUZ1. and that seemed to be the issue with that power rail but APU_CORE is still 4.8 ohms even with the cpu removedLeave a comment:
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+APU_CORE_SOC has 0 ohms resistance to ground. Does anyone know the resistance on a working board?Leave a comment:
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la-l031p acer has 0v on +APU_CORE_SOC
i received this laptop as a backlight issue but i noticed that it wasn't posting. It turns out that the cpu power rails are not working and +APU_CORE_SOC has no resistance to ground. Can someone tell me the resistance to ground for this power rail? -
it boots...Leave a comment:
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was a bad capLeave a comment:
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12.38v is stable on #1. direct short to ground on #2. 0.3 ohmsLeave a comment:
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820-02020 a2338 motherboard has a ppbus short to ground
this machine came to me as DOA and immediately found the issue as a 12v short to ground. Is it okay to inject voltage into that rail or does it have a potential path to the cpu or something? -
can't get the camera to focus on tiny objects but it's an sot23 with R1 as the top marking. CJ3401 is an sot23 also with R1 as the top marking but not sure if it's a matchLeave a comment:
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identifying sot23 on backlight cirucuit of 17" razer rz09-0423
this laptop was damaged by a roof leak at the repair shop that it was at while waiting for a replacement cpu fan. It was given to me to try to save the motherboard which wouldn't power up anymore. The only issue now is that an sot23 marked R1 is missing one of it's three legs. I cannot find schematics for this model but I found a mosfet that has the same label but i'm not sure if it's an actual match. CJ3401 is the one that I found but I have no clue about the true identity of the damaged one. -
it doesn't sound like it is stuck in tablet mode if the touchpad is workingLast edited by kjchatman; 07-07-2025, 07:55 AM.Leave a comment:
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before you do any hardware fixes you should try disabling the ymc.exe service. That is the yoga mode control and sometimes that enough. make sure that the keyboard and mouse will work outside of windows or otherswise it might not be a sensor issue at allLast edited by kjchatman; 07-05-2025, 08:34 AM.Leave a comment:
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check if LID_360D_SW# is 3.3v or no. i think that's the signal for disabling the keyboard/ trackpad when in tablet or tent mode. there is likely a sensor near the camera that isn't working correctly so just look for the resistor with the 3v rail on the other side and run a wire to both sides and that will override and keep LID_360D_SW# at 3.3vLast edited by kjchatman; 07-02-2025, 08:34 AM.Leave a comment:
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a1502 820-4924 doesn't post and won't power up with the charger alone
this computer has no signs of liquid damage. It will power up with both the charger and the battery attached but it doen't start with the 60 watt charger without the battery being attached. When it starts up the vcore shows up for a few seonds then it's powers down and then powers up again. it does seem to charge the battery.. It's hard to troubleshoot because the battery is glued to the casing. -
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