HP 250 G5 X0Q77ES#ABU uszkodzony RT8243AZ pomyłka w lutowaniu.

Witam,
Laptop
HP 250 G5 X0Q77ES#ABU
Płyta BDL50 LA-D704P REV: 4

Wszystko było ładnie pięknie usterka wydawała się prosta 5V LDO uszkodzony okazał się układ PU2 RT8243AZ zwarcie do masy LDO5 p wylutowaniu układu rezystancja wzrosła do kΩ. zamówiłem nowy układ chwile to trwało zanim doszedł. Laptop leżał i czekał rozkręcony i czekał, po otrzymaniu układu nadszedł czas na wlutowanie nowego i tu pojawił się problem, przez pomyłkę zamiast wlutować układ w prawidłowe miejsce PU2, wlutowałem go w nieobsadzone miejsce PUW1. Po podłączeniu zasilacza moim oczom ukazał się dym z nowo wlutowanego układu. Po tym zabiegu płyta martwa rezystancja na rezystorze pomiarowym 2Ω udało mi się zlokalizować zwarcie na PQ8 po jego ściągnięciu rezystancja na rezystorze pomiarowym wynosi 2,86kΩ wydaję mi się że ok. Ale za to na PL8 wydaję mi się za nisko 4,6Ω nie mam schematu do tej płyty czy rezystancja na na PL8 jest poprawna, co jest zasilane przez tą linie. Poniżej pomiary rezystancji na cewkach oraz zdjęcie okolicy PL8 z naniesionymi Pomiarami.



PL1203 -12,2Ω
PL1205 -12,2Ω
PL1206 -22Ω
PL602 -1,5Ω
PL11 -600Ω
PL202 -20kΩ

Hello!

Perform a short circuit test described here on output pad of jumper PJP3 (the pad wit low resistance to ground). Limit the voltage to 5V.

Measure the resistance to ground on jumper PJP2.
Also remove the coil PL602 from the board and measure the resistance to ground on both pads on the place of that coil.

Hello,
I did a short circuit test last night at the output of PJP3 limit with a limit voltage 3V. KBC starts to heat slightly.
Resistance to the ground on the PJP2 13,5kΩ. Below measurement on the coil PL602 below. After removed KBC chip from the board, resistance at PJP3 is 320Ω, which I think still is too low for this line. Resistance was measured without PQ8 on the board.

Udało mi się płytę częściowo przywrócić do życia po wymianie RT8243, PQ8 ,ściągnięciu z płyty uszkodzonego KBC. Po podłączeniu zasilania napięcie 19V na PR203 obecne. obecne również napięcia LDO3 i LDO5. Martwi mnie niska rezystancja na PL8 320Ω. płyta bez KBC czekam dostawę. Przeszukałem forum i znalazłem że w tym miejscu powinno być w kΩ. Czy powinienem się martwić taką niska rezystancją w tym miejscu, jeśli tak to jak mogę zlokalizować przywierający element.

kamil1986 napisał(a):Martwi mnie niska rezystancja na PL8 320Ω.

Yes, this resistance seems too low.

The resistance to ground on output pad of coil PL602 (0,7Ω) is also too low. Perform a short circuit test on this pad. Limit the voltage to 1V.

The low resistance on both coils is unfortunately very likely caused by a damaged APU hybrid.

During the short circuit test at the coil PL602 the coil draw 1,3A. Apu does not heat at all. Also during the short circuit test at the coil PL8 no sign of heating elements on the mother board. I think the resistance is too high for the short circuit test. Is the only way to find shorting element is by lifting every chip, powered by this line? If, of course, APU does not cause a short circuit.

kamil1986 napisał(a):During the short circuit test at the coil PL602 the coil draw 1,3A.

At such current consumption something should be warm. Check the whole board for a warm component, but I'm afraid is is the APU.
If you still can't find anything warm, measure the voltage on the end of test wires (at the point, where they are soldered to the motherboard) during a short circuit test at 1V.

I found UC6 hot at the second short circuit test after removing the chip resistance at the coil PL602 increased from 0,7Ω to 32Ω " that sounds good to me". And at coil PL8 increased from 320Ω to 0,7kΩ, I think still too low at this point.

Yes, the resistance to ground on coil PL602 seems normal now.
The resistance to ground on PL8 is still a bit low, but it will be hard to find the shorted component for now.

Replace the damaged chips, solder all removed components back to the board and test the board.

I decided to lift one by one every chip powered by +5VALW, after lift UC5 the resistance at PL8 increased to 30kΩ, seems to be ok now. According to measurements, I hope the APU has survived. Resistances at all 3V lines are high in kΩ.

Nowy układ KBC dotarł. Czy mogę próbować uruchomić płytę bez układu UC6 w celach diagnostycznych, drugie pytanie czy KBC sam się zaprogramuje?

kamil1986 napisał(a):Czy mogę próbować uruchomić płytę bez układu UC6 w celach diagnostycznych

Yes, you can, but there will probably be no picture on the screen without this chip.

kamil1986 napisał(a):drugie pytanie czy KBC sam się zaprogramuje?

This chip does not support auto programming. It should be manually programmed with programmer.

New KBC on the motherboard after around 3s led beside charging port starts light in white colour. There is a motherboard reaction on the power button 3V, 5V, appears. Power consumption 0,011A after press the power button 0,030A Unfortunately do not have a programmer for KBC chips.

kamil1986 napisał(a):Unfortunately do not have a programmer for KBC chips.

The KBC chip needs to be programmed, the machine will not work without it.
You can buy a pre-programmed KBC chip for this board, or get/borrow the KBC programmer somewhere.

I Purchased SVOD3 programmer. KBC chip has been programmed, after press the power button motherboard starts work but still no picture on the screen, the motherboard power consumption is 100mA fan spinning for the first couple seconds then stops. I tried a couple of different bios files, Every time the motherboard stuck at 100mA.

Measure the voltages to ground on all coils, when the machine is turned on (power LED is turned on).

Hi Matic,
Most likely PU1101 (NCP81206) is damaged, short circuit in VCC pin(13) 20Ω to the ground. +5VS appears before the resistor PR1118, 0V at the PU1101 side. Performed short circuit test at the point marked in the diagram, the voltage was set 5V current consumption 0,2A PU1101 starts to heat. I lifted the chip from the motherboard resistance was increase to 320Ω at this line. I have a second same motherboard as broken one was fully working I decided to take PU1101 and solder it to broken motherboard but most likely I damaged the chip during soldering by hot air after soldering the chip still i had short circuit to the ground at VCC (pin13) then I return the chip to the fully working motherboard but the motherboard does not turn on, now at both motherboard, I have exactly same situation motherboards turns on, but both stuck at 100mA and fan stops spinning after couple second. I have NCP81208 but I am not sure if I can solder this chip instead NCP81206.

The chip PU1101 (NCP81206M) and resistor PR1118 (2,2Ω/5%, package 0603) are damaged almost for sure and needs to be replaced.

kamil1986 napisał(a):I have NCP81208 but I am not sure if I can solder this chip instead NCP81206.

No, these two chips are not interchangeable. Chip NCP81206 has 52 pins, while NCP81208 has only 48 pins.

resistor PR1118 (2,2Ω/5%, package 0603) are damaged almost for sure and needs to be replaced.

Confirmed, the resistance of resistor PR1118 is 52Ω instead 2,2Ω

After replacing NCP81206M and PR1118 laptop works ok, worries me a little bit the resistance at pin13 of NCP81206M is only 74Ω, is it correct resistance at this place?