IBM Thinkpad T43 hangs/can't boot when using power adapter but OK with batt

[spintop]

My T43 is facing some issue recently.

- Laptop works perfectly using the battery alone.
- When used with the power adapter with or w/o batt, it failed to boot some times. If it did boot to Windows, it will hang after awhile.
- The batt can charge when inserted into the laptop.
- F2 fuse is OK

Suspect issue with the MOSFET, but not too sure.
Seek some advice here.

[Tuomo]

Re: IBM Thinkpad T43 hangs/can't boot when using power adapter but OK with batt

My T43 is facing some issue recently.

- Laptop works perfectly using the battery alone.
- When used with the power adapter with or w/o batt, it failed to boot some times. If it did boot to Windows, it will hang after awhile.
- The batt can charge when inserted into the laptop.
- F2 fuse is OK

Suspect issue with the MOSFET, but not too sure.
Seek some advice here.

You need schematic first, then we can try to help you.

[spintop]

Re: IBM Thinkpad T43 hangs/can't boot when using power adapter but OK with batt

this should be it.
BTW, sometimes with the power adapter the laptop will beep 1-3-3-1. but still fail to boot. again with just the battery pack everything OK.

[spintop]

Re: IBM Thinkpad T43 hangs/can't boot when using power adapter but OK with batt

readings noted (refer to page 71)

With Power adapter (rated 16V, 4.5A) only, laptop don't boot usually, sometimes it boot, sometime beep, fan is running.
- Q36
Pin 1,2,3 = 16.5V
Pin 4 " = 1. (High impedance ? I am not sure what is this reading means on the meter)
Pin 5,6,7,8 = 16.5V (VINT16)

- Q13
Pin 1,2,3 = 0.1V
Pin 4 " = 0.1V (with no batt pack, this signal is disable by the controller, U61)
Pin 5,6,7,8 = 16.5V (VINT16)

With Batt pack (12V) only, laptop work perfect
- Q36
Pin 1,2,3 = 0.25V
Pin 4 " = 0V (Controller disable the FET, when no power adapter)
Pin 5,6,7,8 = 11.4V (VINT16)

- Q13
Pin 1,2,3 = 11.4V
Pin 4 " = 18.6V (signal is enable by the controller, U61)
Pin 5,6,7,8 = 11.4V (VINT16)

these 2 MOSFETs seem to be working fine.
I uncertain for the reading "1." in Q36, if this is an issue.

This main board most passive parts are not labelled, so finding them is abit tough.

[Tuomo]

Re: IBM Thinkpad T43 hangs/can't boot when using power adapter but OK with batt

readings noted (refer to page 71)

With Power adapter (rated 16V, 4.5A) only, laptop don't boot usually, sometimes it boot, sometime beep, fan is running.
- Q36
Pin 1,2,3 = 16.5V
Pin 4 " = 1. (High impedance ? I am not sure what is this reading means on the meter)
Pin 5,6,7,8 = 16.5V (VINT16)

- Q13
Pin 1,2,3 = 0.1V
Pin 4 " = 0.1V (with no batt pack, this signal is disable by the controller, U61)
Pin 5,6,7,8 = 16.5V (VINT16)

With Batt pack (12V) only, laptop work perfect
- Q36
Pin 1,2,3 = 0.25V
Pin 4 " = 0V (Controller disable the FET, when no power adapter)
Pin 5,6,7,8 = 11.4V (VINT16)

- Q13
Pin 1,2,3 = 11.4V
Pin 4 " = 18.6V (signal is enable by the controller, U61)
Pin 5,6,7,8 = 11.4V (VINT16)

these 2 MOSFETs seem to be working fine.
I uncertain for the reading "1." in Q36, if this is an issue.

This main board most passive parts are not labelled, so finding them is abit tough.

Those looks ok if those are measured values.

Can you try another Power Adapter.

Try measure CPU voltages during boot.

[spintop]

Re: IBM Thinkpad T43 hangs/can't boot when using power adapter but OK with batt

I tried 2 different power adapter, the problem is the same.

I read that the power up sequence is firstly VINT16 & VREG16 from the power source, then from there generate VCC3SW to start up PMH4. This will next generate the whole range of other voltages to startup the booting.

I measured VCC3SW at a stable 3.3V, I believe this good to start the 2nd stage of voltage generation to power up the laptop.

Any idea what ISYS and LPMODE signals are used for ? on the last page of schematics

thanks

[Tuomo]

Re: IBM Thinkpad T43 hangs/can't boot when using power adapter but OK with batt

I tried 2 different power adapter, the problem is the same.

I read that the power up sequence is firstly VINT16 & VREG16 from the power source, then from there generate VCC3SW to start up PMH4. This will next generate the whole range of other voltages to startup the booting.

I measured VCC3SW at a stable 3.3V, I believe this good to start the 2nd stage of voltage generation to power up the laptop.

Any idea what ISYS and LPMODE signals are used for ? on the last page of schematics

thanks

Unfortunately I am not familiar with this model schematic.

I can try looking it and try figure out how it works.

Are you sure at there is not nec tokin type capasitors, which cause this kind problem with Toshiba?

[Tuomo]

Re: IBM Thinkpad T43 hangs/can't boot when using power adapter but OK with batt

I tried 2 different power adapter, the problem is the same.

I read that the power up sequence is firstly VINT16 & VREG16 from the power source, then from there generate VCC3SW to start up PMH4. This will next generate the whole range of other voltages to startup the booting.

I measured VCC3SW at a stable 3.3V, I believe this good to start the 2nd stage of voltage generation to power up the laptop.

Any idea what ISYS and LPMODE signals are used for ? on the last page of schematics

thanks

I guess ISYS is coming voltage and LPMODE is Low Power Mode.

If ISYS voltage go low LPMODE is activated.

[spintop]

Re: IBM Thinkpad T43 hangs/can't boot when using power adapter but OK with batt

thanks !
I am running out of idea what is wrong in this laptop - works using battery, but cannot boot or hang on power adapter. already tried out 2 different power adapters.
Hope someone has a clue.

[spintop]

Re: IBM Thinkpad T43 hangs/can't boot when using power adapter but OK with batt

Tuomo, how does nec tokin type capacitors looks like ?

[Francisco.s]

Re: IBM Thinkpad T43 hangs/can't boot when using power adapter but OK with batt

Tuomo, how does nec tokin type capacitors looks like ?

Have a look to this pdf.

[spintop]

Re: IBM Thinkpad T43 hangs/can't boot when using power adapter but OK with batt

my laptop is back to life.
Found and replaced 2 components (resistor and ceramic cap) that seems to be corroded, and it worked ever since.
This is the second time i have this problem on the board.

Thanks for your help guys !!!!

[spintop]

Re: IBM Thinkpad T43 hangs/can't boot when using power adapter but OK with batt

someone asked me for a photo. As I have already assembled the laptop, so i wont be opening again anytime soon. In case if u are having the same thinkpad and same issue booting up, keep a look out for cold or corroded joints near the fan area, which is my case.
The difficult thing is spotting them since all the components are super tiny, and i used a magnify glass too. As to why it works on battery, i am not too sure too. Maybe with charger it runs at higher volt of 16V versus 12V on batt, causing the already weaker joints to break. But i am sure given time, the weak joint will break completely and will not boot even with battery.

[carlven]

Re: IBM Thinkpad T43 hangs/can't boot when using power adapter but OK with batt

can you add pics or value of capacitor and resistor?