Samsung chromebook XE350XBA na płycie BA41-02748A / BA92-20198B, grzeje się 3483UK.

Pacjent jak w tytule bez oznak życia ( BA41-02748A - nadruk na laminacie, BA92-20198B - nadruk na naklejce), usterka powstała samoczynnie (ładowanie przez USB-C).

Namierzyłem mocno grzejący się układ 3483UK (czekam na przesyłkę), rezystancje na cewkach powyżej kOHM. Nie posiadam schematu, zastanawiam się czy to kwestia samego układu czy czegoś więcej.

Hello!

Measure the resistances to ground on points A, B, C.

Hello, thanks for your interest in the problem. Below are the measurements without the 3483UK, controller was disassembled:
A) 6 MOHM
B) 165 kOHM
C) 2.1 OHM
Is the capacitor at point "C" short-circuited?

Yes, exactly. There is a short circuit to ground on the capacitor "C".
Perform a short circuit test described here (lesson #3). Start with a voltage limit 1V. If you reached 1V and nothing heats up, rise up the voltage limit to 2V.

rezystancje na cewkach powyżej kOHM

Measurement error, two coils have low resistance, sorry (according to the photo below).

I did a 2V/1.4A short-circuit test, I did not find a hot capacitor, the RT5077A and the CPU heat up to a temperature of about 40C.

ppgg1 ha scritto:I did a 2V/1.4A short-circuit test

Did you performed this test on the point "C"?
If so, measure the resistances on all coils in reference to the point "C".

matic ha scritto:[ Obrazek ]

Point C = Point 1
I made two short-circuit tests, one at point C/ground, the other at point 1/ground. As I wrote above, in both cases the RT5077A and the CPU heat up to a maximum temperature of about 40C after a long time.
Point: C/3 15 kOHM
Point: C/1 0.3 OHM
Point: C/2 110 OHM
Point: C/5 0.88 kOHM
Point: C/4 54 kOHM

I received information that before the fault occurred, there were often problems with charging the battery or detecting the charger.

The chip RT5077A is damaged almost for sure. Remove it from the board and remeasure the resistance to ground on coil #1.

After removing the RT5077A chip, the resistance on coil number 1 is 180 kOHM.
The chips have been ordered and will be delivered in about 3 weeks.

After replacing the chips, the laptop still won't boot. I decided not to continue repairing the laptop, thank you for your help.