La-a999p Anyone have boardview ?

[baddjavo]

Here is schematic if anyone need. La-a999p

Anyone have boardview ?

Problem is after pressing pwr btn led just goes off. If i remove solder-jumper on 5valwp, led stays on. Probably short , need boardview to trace it.

[mon2]

Re: La-a999p Anyone have boardview ?

To check for a short, remove all power. Meter in resistance mode. Measure the resistance to ground of the pin that may be shorting. Post the measurement.

Do you have an adjustable power supply?

If yes, using the power supply at 1volt (not higher!!), you can inject with red power supply probe at short pad, black to ground.

The shorting part will heat up.

[baddjavo]

Re: La-a999p Anyone have boardview ?

i know. Right. But let me show you problem.
After remove pj303 solder jumper. Laptop have normal 3.3 and 5v etc.
So problem iz after that jumper, but where ? 22x places to go. Maybe less.
Its not short. Tried already with lab power supply, no current.

[mon2]

Re: La-a999p Anyone have boardview ?

Remove all power -> measure the resistance to ground of each coil / inductor on the board. Someone is causing an excessive current draw to shutdown the +5VALWP rail.

[AL._.EX]

Re: La-a999p Anyone have boardview ?

Check resistance after Q21, Q22, US2, US1, QV12, QV15, PUM1.

Very similar boardview LA-A998P

[baddjavo]

Re: La-a999p Anyone have boardview ?

Cant open that .brd in boardviewer22 , any easy software recommend ? I will check those, guess manually for now. Just found Q21 ...

[baddjavo]

Re: La-a999p Anyone have boardview ?

After removing J4 jumper after Q21 (voltage on output pins 13, 14 is 5volts) , 3 and 5 always voltage present.

Resistance after J4 is zero. short

[mon2]

Re: La-a999p Anyone have boardview ?

J4 is marked with an '@' symbol which usually means that it is NOT shorted = should be left open.

Was there a factory short on your logic board ?

[baddjavo]

Re: La-a999p Anyone have boardview ?

Yeah, its factory shorted. Found hot spot using lab voltage supply, 4 ampers near UA1 chip. Finger burnt.

[mon2]

Re: La-a999p Anyone have boardview ?

UA1 = audio codec ALC3227 ?

You can remove it and test again. It is only for sound support.

[baddjavo]

Re: La-a999p Anyone have boardview ?

UA1 right. But not that chip, capacitor on picture, just moved cap left him on board. Cap connected on pin 46 of UA1.
Uploaded picture of motherboard just to confirm J4 is factory shorted.
Laptop is working now !

Thx mon2, and AL._.EX appreciate help.

[mon2]

Re: La-a999p Anyone have boardview ?

Good job! Your feedback and closure will help future techs.

[AL._.EX]

Re: La-a999p Anyone have boardview ?

Boardview LA-A998P open Allegro 16.6