Toshiba L855-10P Totally Dead

[laz]

Re: Toshiba L855-10P Totally Dead

Hello guys, I made measurements on U6000 (which is a TI bq24725A).
U6000 datasheet: https://cdn.badcaps-static.com/pdfs/...9485119ff4.pdf
Motherboard schematics (hansie55): https://www.badcaps.net/forum/attach...9&d=1407606750 (-->PAGE 5)

Laptop is dead, battery is not charging.
If you have any suggestions, please do it, i am on a dead end...

This is what I read:

[grahamw01]

Re: Toshiba L855-10P Totally Dead

Hello guys, I made measurements on U6000 (which is a TI bq24725A).
U6000 datasheet: https://cdn.badcaps-static.com/pdfs/...9485119ff4.pdf
Motherboard schematics (hansie55): https://www.badcaps.net/forum/attach...9&d=1407606750 (-->PAGE 5)

Laptop is dead, battery is not charging.
If you have any suggestions, please do it, i am on a dead end...

This is what I read:

Hi Laz,

Sorry the solution didn't work out for you.

I have very little knowledge of how electronics work so I can't help much. I had a quick look at the datasheet for U6000 though. You are not getting any voltage on pin 4 ACDRV because pin 6 ACDET needs to be between 2.4V and 3.15V but your pin 6 is 1.24V. My original value was 2.685V here. Maybe you can use the schematic.

ACDET comes straight from adapter through resistor R6002, voltage drop across R6002 (20.5K) because of R6003 (3.32K) is 16.8V, so if your adapter is 19.5V then ACDET should be about 2.7V. The only thing that can pull this voltage is Q6011 (which you have already replaced) or C6029.

Maybe you can check resistance and voltage on R6002, R6003, check C6029, D6002, Q6011.

I may just be talking nonsense though! I hope someone else can give better advice..

[laz]

Re: Toshiba L855-10P Totally Dead

Hi grahamw01, thanks a lot for the tip. Indeed I am getting 1,24V at R6002 (which was hard to discover). R6002 checked 20,5K. R6003 checked 3.3K. D6002 checked. Q6011 is replaced. My problem now is that i cannot find C6029 on the board.

[grahamw01]

Re: Toshiba L855-10P Totally Dead

Hi Laz, sorry, I hope someone else will respond with a solution because it is beyond me, hence why I asked here in the first place!

[hazardus]

Re: Toshiba L855-10P Totally Dead

I'd change that R6002.

[laz]

Re: Toshiba L855-10P Totally Dead

Hi Laz, sorry, I hope someone else will respond with a solution because it is beyond me, hence why I asked here in the first place!

Sure, no worries! Thanks again graham, I believe I am getting closer to the solution, but I also hope to find a good answer here...

[grahamw01]

Re: Toshiba L855-10P Totally Dead

hi hazardus, why do you say that? he has checked R6002 and R6003 they are the correct resistances, so doesn't that mean they are fine?

I have asked to borrow back the laptop I fixed, so we can compare a few voltages and resistances. I will take values on U6000 and Q6010-12, with and without battery and when its turned on etc.. hopefully we can find what it wrong!

[hazardus]

Re: Toshiba L855-10P Totally Dead

You are right. I didn't realize that he checked the resistance on R6002.

[laz]

Re: Toshiba L855-10P Totally Dead

I have asked to borrow back the laptop I fixed, so we can compare a few voltages and resistances. I will take values on U6000 and Q6010-12, with and without battery and when its turned on etc.. hopefully we can find what it wrong!

That's great news, if you manage to do it!!! I think that if that capacitor is partly short-circuited then the low voltage can be explained. But i still can't locate it.

[grahamw01]

Re: Toshiba L855-10P Totally Dead

Hi Laz, got the laptop, I'll try to take some values within the next hour or so.

[laz]

Re: Toshiba L855-10P Totally Dead

Hi Laz, got the laptop, I'll try to take some values within the next hour or so.

I have no words man..... Can you also try to locate C6029?

[grahamw01]

Re: Toshiba L855-10P Totally Dead

no battery not turned on

Q6010 pins 5-8 19.3V, pin 4 25.15V, pins 1-3 19.31V.

Q6011 pins 5-8 19.3V, pin 4 25.15V, pins 1-3 19.3V.

Q6012 pins 5-8 19.3V, pin 4 3.1V, pins 1-3 3.1V.

U6000;
pin 1 19.3V
pin 2 19.3V
pin 3 19.3V
pin 4 25.2V
pin 5 3.4V
pin 6 2.7V
pin 7 0
pin 8 3.4V
pin 9 3.4V
pin 10 1.54V
pin 11 3.1V
pin 12 3.1V
pin 13 3.1V
pin 14 cant get to
pin 15 think 0 (difficult to get to)
pin 16 6V
pin 17 6V
pin 18 cant get to
pin 19 3.1V
pin 20 19V

[grahamw01]

Re: Toshiba L855-10P Totally Dead

I will post the results as I do them, BTW by the looks of it C6029 should be in between R6002 and R6003 on the board but its not, I guess its not really required

[grahamw01]

Re: Toshiba L855-10P Totally Dead

also D6002 (still no battery and not turned on) the 2 pins not connected to R6003 are 19.3V

[grahamw01]

Re: Toshiba L855-10P Totally Dead

charging battery not turned on

Q6010 pins 5-8 19.3V, pin 4 25.15V, pins 1-3 19.3V.

Q6011 pins 5-8 19.3V, pin 4 25.15V, pins 1-3 19.3V.

Q6012 pins 5-8 19.3V, pin 4 12.3V, pins 1-3 12.3V.

U6000;
pin 1 19.1V
pin 2 19.1V
pin 3 19.1V
pin 4 25.0V
pin 5 3.4V
pin 6 2.7V
pin 7 400mV
pin 8 3.4V
pin 9 3.4V
pin 10 1.54V
pin 11 12.34V
pin 12 12.34V
pin 13 12.34V
pin 14 cant get to
pin 15 think 0 (difficult to get to)
pin 16 6V
pin 17 18.75
pin 18 cant get to
pin 19 12.6V
pin 20 18.7V

D6002 pins not connected to R6003 are 19.3V

[grahamw01]

Re: Toshiba L855-10P Totally Dead

charging battery and turned on

Q6010 pins 5-8 19.0V, pin 4 24.9V, pins 1-3 19.3V.

Q6011 pins 5-8 19.0V, pin 4 24.9V, pins 1-3 19.3V.

Q6012 pins 5-8 18.9V, pin 4 12.5V, pins 1-3 12.5V.

U6000;
pin 1 19.1V
pin 2 19.1V
pin 3 19.1V
pin 4 25.0V
pin 5 3.4V
pin 6 2.7V
pin 7 600mV
pin 8 3.4V
pin 9 3.4V
pin 10 1.5V
pin 11 12.34V
pin 12 12.34V
pin 13 12.34V
pin 14 cant get to
pin 15 think 0 (difficult to get to)
pin 16 6V
pin 17 18.75
pin 18 cant get to
pin 19 12.6V
pin 20 18.7V

D6002 pins not connected to R6003 are 19.3V

[grahamw01]

Re: Toshiba L855-10P Totally Dead

I don't understand why you only get 1.24V on pin 6! Are you sure your Vin is 19V? Maybe it's just U6000 is broken..

[laz]

Re: Toshiba L855-10P Totally Dead

graham thanks again for this valuable effort.
So far I notice an absence of voltage at many pins.

My values with no battery.
Q6010: pins 5-8: 19V. All others 0V
Q6011: all pins are 0V
Q6012: pins5-8: 0V pins1-3: 0,42V pin4: 0,2V
D6002: pin3:0,62V pin1:0V pin2:1,24V

U6000 (I've posted them)
pin14 is ground
pin15 is pin4 Q6001
pin18 is pin4 Q6000

[khaahk]

Re: Toshiba L855-10P Totally Dead

The many voltages are absent because the ACDET is low. In this case, as you have checked the resistors, then the U6000 is the most likely failed part. What is the resistance from ACDET to GND?

[laz]

Re: Toshiba L855-10P Totally Dead

Maybe U6000 has internal leak? ACDET to GRND is 3,2K.