LENOVO U330 DA0LZ5MB8B0 Quanta LZ5 REV:D

[kokono]

Hi all
i have this board with strange problem
when i received this laptop ,i found a bad capacitor , i removed it
now, when power on motherboard, nothings
i checked +PWR_SRC , about 0.7 volt
when one side of PL6 ist float ,i measuring about 7 volt , this voltage ist normal ?
any opinion ?

[BlueMidnight]

Re: LENOVO U330 DA0LZ5MB8B0 Quanta LZ5 REV

+PWR_SRC serve a dual purpose. It charges the battery, and it is also the main power rail for the rest of the board. But, everything connected to +PWR_SRC can run off of 7V just fine. I don't have one of those boards to compare it too, but that doesn't sound terrible.

On a perfectly working board, the output of the charging buck regulator should be slightly higher than the battery voltage (probably up to ~8.4V). With no battery connected, it certainly might be configured to output just 7V.

So, right now the problem just seems to be a short of some kind pulling down the rail voltage when PL6 is connected.

[SMDFlea]

Re: LENOVO U330 DA0LZ5MB8B0 Quanta LZ5 REV

Could you upload the schematic

[kotnatan]

Re: LENOVO U330 DA0LZ5MB8B0 Quanta LZ5 REV

http://**************/load/noutbuki/.../307-1-0-39765

http://**************/load/noutbuki/.../307-1-0-39764

[SMDFlea]

Re: LENOVO U330 DA0LZ5MB8B0 Quanta LZ5 REV

http://**************/load/noutbuki/.../307-1-0-39765

http://**************/load/noutbuki/.../307-1-0-39764

Thanks for the links.I`ve tried to join remont-aud before but i can`t use the site with google translate.

[BlueMidnight]

Re: LENOVO U330 DA0LZ5MB8B0 Quanta LZ5 REV

Schematic attached.. [MOD EDIT] link to schematic - https://www.badcaps.net/forum/troubl...ev-d-schematic

[SMDFlea]

Re: LENOVO U330 DA0LZ5MB8B0 Quanta LZ5 REV

Thanks for the schematic .

[kokono]

Re: LENOVO U330 DA0LZ5MB8B0 Quanta LZ5 REV

+PWR_SRC serve a dual purpose. It charges the battery, and it is also the main power rail for the rest of the board. But, everything connected to +PWR_SRC can run off of 7V just fine. I don't have one of those boards to compare it too, but that doesn't sound terrible.

On a perfectly working board, the output of the charging buck regulator should be slightly higher than the battery voltage (probably up to ~8.4V). With no battery connected, it certainly might be configured to output just 7V.

So, right now the problem just seems to be a short of some kind pulling down the rail voltage when PL6 is connected.

thx for reply and sorry for my delay
i tested all part and wont cant find any element that be short circuit

[BlueMidnight]

Re: LENOVO U330 DA0LZ5MB8B0 Quanta LZ5 REV

Something must be dragging down that power rail.

In situations similar to this, sometimes there is a shorted high side FET in one of the buck regulators (the FET connected between +PWR_SRC and the output power rail). These can be found with diode mode measurements across the FET.

It may also be useful to measure the voltage on all the coils. You may even find that ~0.7V getting onto one of them. Measuring resistance to ground on all the coils may provide clues as well.

You can inject a very small voltage onto +PWR_SRC using a bench power supply (if you have one). With enough current, the bad component may get hot. Or not. Depending.

And it's not easy on this particular board, but as a last resort you can desolder other components to isolate parts of the board (just like you desoldered PL6).

[kokono]

Re: LENOVO U330 DA0LZ5MB8B0 Quanta LZ5 REV

i checked all mosfet in board and measure ohm model for short circuit.
all things is ok

[BlueMidnight]

Re: LENOVO U330 DA0LZ5MB8B0 Quanta LZ5 REV

It's also possible for there to be a problem with PU7 or the surrounding components. For example, it may not be changing the duty cycle to compensate for loading on the output. It's easy enough to just measure all the pins of PU7 and look for anything strange. This should be done with PL6 connected.

[kokono]

Re: LENOVO U330 DA0LZ5MB8B0 Quanta LZ5 REV

i changed PU7 and nothings

[kokono]

Re: LENOVO U330 DA0LZ5MB8B0 Quanta LZ5 REV

and is it possible describe about ACDC_ID pin.
whats this ? how much voltage ?

[BlueMidnight]

Re: LENOVO U330 DA0LZ5MB8B0 Quanta LZ5 REV

The actual voltage readings for all these checks you are doing are important. I can only help in the most vague terms without them.

The ACDC_ID signal identifies the wattage of the AC adapter to the motherboard. It is the center point of a voltage divider consisting of 2 resistors in series between 3.3V and ground.

The first resistor is 750 ohms and is connected between 3V and the ID pin. The second resistor is built into the AC adapter itself (in the plug) and connects the ID pin to ground.

Different wattage adapters have different resistors inside them. This creates different voltage levels on the ID pin. The voltage level identifies the wattage, and will obviously be somewhere between 0V-3V.

There will be no voltage on the ID pin if the 3V switching regulator on the board isn't powered up. And yours won't be since your main power rail isn't working.

[kokono]

Re: LENOVO U330 DA0LZ5MB8B0 Quanta LZ5 REV

i removed PU6 , PU5 , PU1and PQ2
but dont change .i checked all PWR_SRC line ,all things ist ok and for sure i removed Pu6, pu5 pu1 pq2 . nothings
any opinion ?

[BlueMidnight]

Re: LENOVO U330 DA0LZ5MB8B0 Quanta LZ5 REV

With PL6 connected, the AC adapter connected, and the battery disconnected, what are the voltages on all pins of PU7?

[SMDFlea]

Re: LENOVO U330 DA0LZ5MB8B0 Quanta LZ5 REV

Whats the voltage on PQ21 pin 5 ,have you tested PR102,PR106,PR107,PC96,PC97, and have you tried with the CMOS battery

[kokono]

Re: LENOVO U330 DA0LZ5MB8B0 Quanta LZ5 REV

All pin in PU7 :

1 >19.6v
2 >19.6v
3 >18.3v
4 >20v
5 >3.3v
6 >2.6v
7 >0
8 >0
9 >0
11 >0.7v
12 >0.8v
13 >0.8v
15 >0
16 >6v
17 >5.6v
18 >0.8v
19 >0.8v
20 >19.4v

[kokono]

Re: LENOVO U330 DA0LZ5MB8B0 Quanta LZ5 REV

Whats the voltage on PQ21 pin 5 ,have you tested PR102,PR106,PR107,PC96,PC97, and have you tried with the CMOS battery

PQ20 :G ,D ,S 20v
PQ21 :G ,D ,S 20v
in PU7
ACN & ACP 19.6v

[SMDFlea]

Re: LENOVO U330 DA0LZ5MB8B0 Quanta LZ5 REV

What voltage are you getting on +3.3V_ALW2 ,and have you attatched the (good 3V) CMOS battery