Satellite A200 killed by accident.

[fabiog]

Have two Toshibas A200 one that only works with battery does not start with charger the leds just switch on and then off quickly.
since had another working A200 with same board I decided to measure voltages on both I figured out that the chip tps51120 seems to supply 19v,3v and 5v on the new one that is until I got a spark while I was measuring 19v on that chip on the new pc (must have touched two pins at once,not sure) long story short now the new computer has no life ,the fuses seem OK i tested them with no power and with multimeter showed 0.
On page 39 of the schematic there is no 3v and no 5v but still get 19v from the
tps51120 chip.
So something is not putting enough current or maybe the tps51120 chip has fried.

Any help would be appreciated.

[b700029]

Re: Satellite A200 killed by accident.

You say "no 3v and no 5v" but there are at least 2 3.3v and 5v rails --- 5vsb/3.3vsb and the main 5v/3v rails.

The TPS51120 has two linear regulators for the standby voltages. Do you get any voltage on pins 19 and 21? They should be 3.3v and 5v, respectively.

[fabiog]

Re: Satellite A200 killed by accident.

There is no current on those pins ,only pin 22 gets 19v and before Vref2 (pin 4) used to get 2v and the hdd light used to flash,now nothing.

[fabiog]

Re: Satellite A200 killed by accident.

Just to make sure I'm checking correctly I place red probe on one of the pins and the black on any ground source.
On page 35 where it states +5VALW TO +5VS ,U36 does not have 5v, +3VALW TO +3VS U38 has no 3v ,

[b700029]

Re: Satellite A200 killed by accident.

If I'm reading the schematic correctly and it's similar to other laptops, the 5VALW/3VALW rails are only powered when the laptop is turned on.

But no voltage on the TPS51120 LDO pins with an input voltage does mean the TPS51120 is dead --- and if you caused a 5-19V short (the 19V in and 5V out pins are adjacent), you may have damaged a lot of other stuff on the VL rail. The 3.3V LDO output being close by as well also means there's the potential to kill whatever is on that rail, although from the schematic it looks like there's... nothing connected to that one. It's intended for the RTC but that gets its power somewhere else.

[fabiog]

Re: Satellite A200 killed by accident.

So now the best chance is to replace that chip and see if it gets at least the power leds.
does it have to be the same chip or a similar one?

[fabiog]

Re: Satellite A200 killed by accident.

will need a heat station to remove this chip as a soldering iron will seem impossible.

[b700029]

Re: Satellite A200 killed by accident.

So now the best chance is to replace that chip and see if it gets at least the power leds.
does it have to be the same chip or a similar one?

If you want to substitute you will need to check the datasheets to ensure the pinouts and specifications are the same. There are several variants of the '51120 like Induastrial Commercial etc. temperature range and that shouldn't matter, but it must be a TPS51120.

[fabiog]

Re: Satellite A200 killed by accident.

I found a 51120 on another computer but the battery controller on the A200 was damged when I tried to remove it for another test.
If I replace the 51120 and remove the battery controller will the computer work but without the ability to charge the battery or does it need the battery controller in this case ISL6251 page 38 of schematic.

[b700029]

Re: Satellite A200 killed by accident.

It should still work from AC adapter without the charger.

[fabiog]

Re: Satellite A200 killed by accident.

I replaced the 51120 and the lights went on and then off ,there is now a short somewhere because when i plug in the power adapter into the DC jack there is a spark and the current no longer displays 19v only about 1v.
and some leds (power,battery) keep flashing blue and orange.

[fabiog]

Re: Satellite A200 killed by accident.

Will try to remove the DC jack cable and test it on it's own ,to make sure that it's not at fault.

[b700029]

Re: Satellite A200 killed by accident.

I replaced the 51120 and the lights went on and then off ,there is now a short somewhere because when i plug in the power adapter into the DC jack there is a spark and the current no longer displays 19v only about 1v.
and some leds (power,battery) keep flashing blue and orange.

You might've killed the replacement '51120 too, due to a shorted MOSFET. Check the one that the '51120 drives.

[fabiog]

Re: Satellite A200 killed by accident.

I'm not sure which one does that ,on page 39 of schematic which one do you think it is?
Thanks so far for your help on this.

[fabiog]

Re: Satellite A200 killed by accident.

I'm thinking that they are the PQ21-24 mosfets since they are linked to the DRV outputs.
Now if I remove them one by one hopefully the short will be removed.

[b700029]

Re: Satellite A200 killed by accident.

Yes, those are the ones.

You can open PJ18 and see if the short still persists; if it doesn't then the problem is in the circuit on page 39.

[fabiog]

Re: Satellite A200 killed by accident.

I removed all the mosfets pq21-24 and short still remains how do I open the PJ18?

[fabiog]

Re: Satellite A200 killed by accident.

PJ18 is a strip of solder.

[fabiog]

Re: Satellite A200 killed by accident.

OK I removed the solder and it's a curcuit underneath which was closed with the solder ontop of it.Removing the solder opened it like you said.
I opened it and still the short remains ,will remove the 51120 and see what happens.

[b700029]

Re: Satellite A200 killed by accident.

You opened PJ18... and where are you still seeing the short across? If it's across the adapter input then look somewhere else, because opening PJ18 disconnects the 51120 and the related rails from the rest of the power circuitry.