Lenovo G555 LA-5972P Martwy

Witam. Pacjent jak w temacie. Układ zabezpieczony.
Na PR302 mamy 14V.
Na bramkach PQ301 i PQ302 mam 19,77V
Profilaktycznie wymienione PQ301 PQ302 oraz PU301. Efekt bez zmian.
Proszę o pomoc w zlokalizowaniu usterki.

Obsada:

MB: LA-5972P
REV: 1.0
CPU: AMM320DB022GQ
GPU: 216-0749001
NB: 216-0752001
SB: 218-0660017
KBC: KB926QF E0

Battery connected?
Measure voltages on all pins of PQ302.

Battery connected?

Only Motheboard

PQ302
n.1,2,3-19,8V
n.4-19,8V
n.5,6,7,8-14V

Measure voltages on all pins of PU101.
3V RTC battery is charging?

PU101

n.1-2,96V
n.2-3,26V
n.3-3,84V
n.4-GND
n.5-2,95V
n.6-3,26V
n.7-0,07V
n.8-19.70V

RTC-3V

Measures the voltages in points indicated by a green circle.

Zmierz napięcia na drenach i bramkach PQ301 oraz PQ302.

EDIT: Nie zauważyłem, że wyniki już podałeś, przepraszam. Zrób próbę zwarciową w gałęzi B+ (napięcie 19V, prąd zacznij od 0,2A).

PQ301
n.1,2,3-19,8V
n.4-19,8V
n.5,6,7,8-20,3V
PQ302
n.1,2,3-19,8V
n.4-19,8V
n.5,6,7,8-13,9V

Nie ma zwarcia w linii B+

mmike napisał(a):PU101

n.1-2,96V

Correct value is 4V.

Remove PU101. If the voltage on pin 1 of PU101 remains the same it is probably bad zener diode PD102.

Po zdjęciu PU101 na n.1-3,25V

Check resistor PR109. It should be 10kΩ.
If it is ok replace zener diode PD102. It is 4.3V.

If you still get too low voltage measure resistance to ground on pad 1 of PU101.

Leave the PU101 desoldered from the board, until you get the correct voltage on pad 1.

PR109-10kOhm

Wymienione PD102 oraz PU101. Efekt bez zmian.

Measure resistance to ground on pin 1 of PU101.

8kOhm

Do the test described here on pin 8 of PQ302:
post5699.html#p5699

Machine

Zrób próbę zwarciową w gałęzi B+ (napięcie 19V, prąd zacznij od 0,2A).

Nie ma zwarcia w linii B+

Measure resistance to ground on power rail B+

It could be conductive path between power rail B+ and ground, which is not dead short, but resistance in range of 500Ω or so.

B+ -149kOhm

Measure resistance on resistor PR101 without desoldering it.