toshiba

[xpzone]

hi all
i have dead toshiba l650-108
-charger is ok
-power jack is ok
no power no led when put charger but when i mesure battery connector on motherboard i found v 3.4
- 18.5 v its ok on motherboard

plz help
thanks in advance

[tomodachi]

Re: toshiba

can you measure 3.3 or any other voltage on power on button ? and did you try clear CMOS ?

[mattbrad2]

Re: toshiba

5v rail is damaged probably. You'll probably need a variable power supply to "smoke" out the bad component(s).

[net2005]

Re: toshiba

5v rail is damaged probably. You'll probably need a variable power supply to "smoke" out the bad component(s).

can you give some instructions on how to perform this task? I have variable PS but not sure how to smoke out bad components with it.

[xpzone]

Re: toshiba

here attachement for toshiba
cmos cleared
explain me * 5v rail

[mattbrad2]

Re: toshiba

can you give some instructions on how to perform this task? I have variable PS but not sure how to smoke out bad components with it.

Turn both knobs on your power supply all the way down to 0. Connect your black to ground obviously then you'll probably have to solder a small wire to a point on the motherboard on the backside of its short circuit protection. You usually have a P-channel mosfet directly on the positive of the DC jack along with a ceramic cap or 2. Connect your power supply to the drain side of the mosfet or somewhere after that on the main rail. Slowly turn your voltage knob up while turning your amp knob even slower. The path of least resistance (or most resistance in this case I suppose) will be your shorted component. You're looking to have your power supply at about an amp of power at no more than 5 volts. This will really start to heat up the shorted component and it will be easily found with an IR heat gun (about $20 at the local auto parts store). More often than not you won't be able to hit an amp much less 5 volts. Don't worry.. it'll still be smoking hot somewhere on the board and it'll give you a good starting point to find that bad component.

[fabiog]

Re: toshiba

Turn both knobs on your power supply all the way down to 0. Connect your black to ground obviously then you'll probably have to solder a small wire to a point on the motherboard on the backside of its short circuit protection. You usually have a P-channel mosfet directly on the positive of the DC jack along with a ceramic cap or 2. Connect your power supply to the drain side of the mosfet or somewhere after that on the main rail. Slowly turn your voltage knob up while turning your amp knob even slower. The path of least resistance (or most resistance in this case I suppose) will be your shorted component. You're looking to have your power supply at about an amp of power at no more than 5 volts. This will really start to heat up the shorted component and it will be easily found with an IR heat gun (about $20 at the local auto parts store). More often than not you won't be able to hit an amp much less 5 volts. Don't worry.. it'll still be smoking hot somewhere on the board and it'll give you a good starting point to find that bad component.

The power supply I have has 3 outputs black ,green (ground) ,red. would one connect only the red and ground or all three negative+ground+positive.

[mattbrad2]

Re: toshiba

The green is simply a earth ground. It isn't connected to any electronics. Use your black and red only. The green is there for a ground reference. I would unplug that probe and let the power supply use itself as a chassis ground.

[net2005]

Re: toshiba

Turn both knobs on your power supply all the way down to 0. Connect your black to ground obviously then you'll probably have to solder a small wire to a point on the motherboard on the backside of its short circuit protection. You usually have a P-channel mosfet directly on the positive of the DC jack along with a ceramic cap or 2. Connect your power supply to the drain side of the mosfet or somewhere after that on the main rail. Slowly turn your voltage knob up while turning your amp knob even slower. The path of least resistance (or most resistance in this case I suppose) will be your shorted component. You're looking to have your power supply at about an amp of power at no more than 5 volts. This will really start to heat up the shorted component and it will be easily found with an IR heat gun (about $20 at the local auto parts store). More often than not you won't be able to hit an amp much less 5 volts. Don't worry.. it'll still be smoking hot somewhere on the board and it'll give you a good starting point to find that bad component.

Thanks for the tip

[fabiog]

Re: toshiba

The green is simply a earth ground. It isn't connected to any electronics. Use your black and red only. The green is there for a ground reference. I would unplug that probe and let the power supply use itself as a chassis ground.

Thanks for the reply ,I have a power supply here in the shop that was left behind by a previous owner and it doesn't seem complete it has a 3 pin wire with banana jacks on both black and red wire on one side and the other side is stripped with no connecter.
I also have various double sided alligator clipped cables ,I have seen on the net premade banana to alligator cables, would it work to just connect alligator cable to one of the stripped copper wires and the other clip to the board.Or must I first get banana jacks for those stripped wires and then connect alligator clip to the banana jack instead.(to be safer).

Thanks