Toshiba L670 power problem

[elerepair]

Hello folks!

So - I have this Toshiba L670 with a power problem. Laptop came in with corrupt BIOS, reflashed BIOS, laptop booted fine, and eventually it came in for repair again.

Symptoms - AC only - Adapter light ON, when trying to power up - Power led blinks, and it resets to beginning.
With battery and AC - sometimes it powers up, eventually shuts down due to battery being empty (Bat led blinks, and beeps. !! charger still connected!!)

Scope measurements -- everything is fine til VIN is converted to B+ (schematic page 36 (S:36)
VIN is nice straight 19.1V, but after 3 resistors it starts to oscillate. (*)
+5VALW and +3VALW is present.
when power button is ðressed - B+ drops down to 0 and resets.

I cannot find the problem. Is the "PU6" (S:39) defective, shorting something out, or the problem is somewhere else ? Any help ?

(*) --- I could try to take pics of my scope, if that helps.

Thanks in advance!

P.S. -- this mobo has BIOS and EC, as far as I know, is that right ?
If so -- where to get dump for EC ?

[elerepair]

Re: Toshiba L670 power problem

nobody?

[alihomee]

Re: Toshiba L670 power problem

check ec chip for voltages and also on battery connector

[ravi_1617]

Re: Toshiba L670 power problem

plug charger and charge battery fully in off condition laptop,then disconnect charger & run on battery only .see what happens

[atsio]

Re: Toshiba L670 power problem

Probably problem with charger circuitry.

[ravi_1617]

Re: Toshiba L670 power problem

is it working fine in battery power.If yes then its NEC TOKINE problem

[atsio]

Re: Toshiba L670 power problem

is it working fine in battery power.If yes then its NEC TOKINE problem

That's a compal board, not an Inventec, where you usually can find the Nec Tokin.

[dj_ricoh]

Re: Toshiba L670 power problem

find pu5 and post the values from there. ISL6251 AHAZ

with charger and battery
with charger without battery
only with battery.

[elerepair]

Re: Toshiba L670 power problem

find pu5 and post the values from there. ISL6251 AHAZ

with charger and battery
with charger without battery
only with battery.

AC only:
19=15.7V
20=15.5V
22=1.5V
(rest is mV or 0)

AC + BATT
1=5.11V
2=5V
3=2.89V
5=5V
6=5V
8=2.3V
10=0.5V
11=0.6V
15=5.1V
16=4.7V
17=4.7V
18=3.5V
19=11.3V
20=11.3V
21=3.5V
22=3.5V
24=11.3V
=====================
BATT pin -- 3.5V
as per schem -- PQ17 -- AO4466. board has AO9636
but has 11.4V as on charger circuit.

[elerepair]

Re: Toshiba L670 power problem

looks to me that charger circuit is working fine. low voltage might been due to shitty battery.

Will check EC when I get back home.
and whats up with B+ ? on scope it looks like normal DC voltage, but has a bump down every second or so. and when Button is pressed it drops dramatically ?

[atsio]

Re: Toshiba L670 power problem

AC only:
19=15.7V
20=15.5V
22=1.5V
(rest is mV or 0)

Yes everything is fine

[dj_ricoh]

Re: Toshiba L670 power problem

Yes everything is fine

so DCIN its 0? do you think its ok?
dcin needs to be 19v with ac only and battery

[dj_ricoh]

Re: Toshiba L670 power problem

check the fets near the dc connection and see if one its culprit!

[atsio]

Re: Toshiba L670 power problem

so DCIN its 0? do you think its ok?
dcin needs to be 19v with ac only and battery

That is what I am saying in my reply. The donkey is dead and they are trying to resurrect it. Problem in charger circuit.

[elerepair]

Re: Toshiba L670 power problem

Yes everything is fine

yeah -- DCIN is 0v as it's only charger. And PQ11 is off.
I get 16V on PQ11 without battery -- and it drops down to 10V with battery.

What I'm concerned of - is the B+
check image for more.


is there a short in volt rails ?

[fddizon]

Re: Toshiba L670 power problem

could be. check b+ vs grnd