Toshiba L755-13N no power.

[rickybucalan]

hello everyone i need your help.

i got this L755 i3 laptop with no power. can't find right schematic diagram (DA0BLGMB6D0).

I found shorted fets nikos P1203ED replace with new one but it still get shorted too.

pls. see attached picture of some test i made.

[ala_borbe]

Re: Toshiba L755-13N no power.

try this

[meritosari]

Re: Toshiba L755-13N no power.

try this:

[rickybucalan]

Re: Toshiba L755-13N no power.

hello guys i found shorted line that suppose to be not.

on page 36. system 5v/3v PU5 pin 6VIN is shorted

i already remove PU5 it still shorted

i also remove some caps PC85, PC74 on the same line still got shorted. dont no were to find more.

need help tnx...

[meritosari]

Re: Toshiba L755-13N no power.

so 19v all short-circuit path. try searching in the scheme of the word "vin". from page 37 onwards. so many caps in the vin lines.

I saw in the scheme have been marked with a line box D3B

[rickybucalan]

Re: Toshiba L755-13N no power.

so 19v all short-circuit path. try searching in the scheme of the word "vin". from page 37 onwards. so many caps in the vin lines.

I saw in the scheme have been marked with a line box D3B

i still cant find the fault component. here i attached file on page 36,37,38,39 and 41. i mark red line that are shorted and even though i removed all caps in the line including ics U3, PU4 PU1,PU8,PU5 and mosfets that mark O.

any idea. gu

[meritosari]

Re: Toshiba L755-13N no power.

+vtt rails short?

did you try isolate by remove PL4, so we focus on vin rails?
maybe pq13,pq18, pq23 are short too

[rickybucalan]

Re: Toshiba L755-13N no power.

+vtt rails short?

did you try isolate by remove PL4, so we focus on vin rails?
maybe pq13,pq18, pq23 are short too

+vtt is short

yeah.i removed that also but the short is still on +vtt line

PQ13, PQ18 PQ23 is not shorted.

[meritosari]

Re: Toshiba L755-13N no power.

I still can not understand, if from page 36 to page 41 + vin has a short-circuit, should pq20 on pins 4 and pq15 on pin 3 is also a short-circuit

quickly find a short-circuit path usually use a PSU that has a current and voltage limits

to isolate pu8 of rail + vin try to lift pr42, because small parts I used to simply shift course and avoid the loss of these components. I often use two pieces of solder to slide

[rickybucalan]

Re: Toshiba L755-13N no power.

I still can not understand, if from page 36 to page 41 + vin has a short-circuit, should pq20 on pins 4 and pq15 on pin 3 is also a short-circuit

quickly find a short-circuit path usually use a PSU that has a current and voltage limits

to isolate pu8 of rail + vin try to lift pr42, because small parts I used to simply shift course and avoid the loss of these components. I often use two pieces of solder to slide

its really confusing why it still shorted even i removed everything in this line...

from PQ15, PQ20,Pc136, pc132, pr46, pr47, pq1....

[Ramee]

Re: Toshiba L755-13N no power.

Could be shorted everywhere, if that's the case. intel chip responsible.
Try to check big coils and those smd caps under intel chip, if they are shorted.

[ktmmotocross]

Re: Toshiba L755-13N no power.

if u dont wanna removing capacitors one by one, get a PSU and put some power to that rail to show shorted components

[rickybucalan]

Re: Toshiba L755-13N no power.

I still can not understand, if from page 36 to page 41 + vin has a short-circuit, should pq20 on pins 4 and pq15 on pin 3 is also a short-circuit

quickly find a short-circuit path usually use a PSU that has a current and voltage limits

to isolate pu8 of rail + vin try to lift pr42, because small parts I used to simply shift course and avoid the loss of these components. I often use two pieces of solder to slide

tnx guys it look quiet good for now i found and solve the issue for VIN rail. but i still have short in +vtt line.

[ktmmotocross]

Re: Toshiba L755-13N no power.

vtt is for cpu so remove processor and coil

[rickybucalan]

Re: Toshiba L755-13N no power.

vtt is for cpu so remove processor and coil

cpu romoved and PL4 including Pc142, pc21, pc143 and pc 139 and its still shorted to ground.

it could might be +1.05v line?

[meritosari]

Re: Toshiba L755-13N no power.

How many ohm you call is short, if like 0.010 ohm I think its ok for +1.05V rails
Try search on this forum about +1.05 rail

[rickybucalan]

Re: Toshiba L755-13N no power.

How many ohm you call is short, if like 0.010 ohm I think its ok for +1.05V rails
Try search on this forum about +1.05 rail

im using digital multimeter. checking Caps

when testing in diode mode from ground to pin it reads 0.009v and 0.000v other side.

when testing in continuity mode from ground to pin its beeps both end

in ohms mode it reads from ground to pin 022.5 ohm and 000.0 ohm

which one is the best way to find short?

[rickybucalan]

Re: Toshiba L755-13N no power.

again after i found shorted caps on VIN line and tested it. it short again this time in PL8 get shorted. lifted up short goes to +3vpcu

removed Caps pc145 and pc226 still shorted.

[v11]

Re: Toshiba L755-13N no power.

try this

Thank you for schematic....



BR

[borbooroski]

Re: Toshiba L755-13N no power.

who cam help me read all motherboard faulty's i really need help?