Acer aspire 4349 shorted

[sasser]

i got one acer aspire 4349 shorted somewhere till now i cant trace.
i feel hot when touch with finger on PQ23 (AOL1413) and i found this mosfet already blown. i know blown when i test with continuity test and i got beep sound. i think rail 19v was shorted

i try replace with AO4433 for testing and also hot when touch with finger. i dont know how to trace where short. please help me.



please refer attachement

[bicalov]

Re: Acer aspire 4349 shorted

To give an idea follow the link.
https://www.badcaps.net/forum/showthread.php?t=46853

[sasser]

Re: Acer aspire 4349 shorted

To give an idea follow the link.
https://www.badcaps.net/forum/showthread.php?t=46853

lastly i need to learn howto inject power to find hot component. commonly brown caps, till now i cant see which cap or damage component

[bicalov]

Re: Acer aspire 4349 shorted

Didn't want to offend you.
It was not only about inject, also trace a short, which was your question

[sasser]

Re: Acer aspire 4349 shorted

Didn't want to offend you.
It was not only about inject, also trace a short, which was your question

my question is in first post. i dont know how to start but i give some info when im measure the component. u give me to link of your thread and i know i need to do jumper or inject power to find shortage or hot component. if u can help me thanks so much . im also can share what i learn from my case and update for others forumer here

[bicalov]

Re: Acer aspire 4349 shorted

As you can see in my thread, I'm stuck for the moment, because I am building lab psu to inject current. When ready I have to connect the 3.3V and start with low current on the last PQ23 I took out. As the instructions go, I have to increase the current little by little till I find the component which get hot (=shortcut)
For me the first time I going to do this, so it is exciting to find out.

[sasser]

Re: Acer aspire 4349 shorted

As you can see in my thread, I'm stuck for the moment, because I am building lab psu to inject current. When ready I have to connect the 3.3V and start with low current on the last PQ23 I took out. As the instructions go, I have to increase the current little by little till I find the component which get hot (=shortcut)
For me the first time I going to do this, so it is exciting to find out.

i may to try with 15v on leg 5 PQ23

[meritosari]

Re: Acer aspire 4349 shorted

i may to try with 15v on leg 5 PQ23

Don't do that!! too high. its more safely start from 0.5V and 0.5A and don't high than 1.0V

[sasser]

Re: Acer aspire 4349 shorted

hye meritosari im remove pq23 and now i injected 5.0v only and i found mosfet on PQ26 was hot.


for measure on others parts more info
1. im removed PQ23 and then check for short to gnd PL5 and PL3 the value is = 243.4 ohm
2. check for short in PR122 i got 20.1ohm
3. im check for short to gnd on PQ23 pin 5 also i got 20.5ohm

[meritosari]

Re: Acer aspire 4349 shorted

hye meritosari im remove pq23 and now i injected 5.0v only and i found mosfet on PQ26 was hot.


for measure on others parts more info
1. im removed PQ23 and then check for short to gnd PL5 and PL3 the value is = 243.4 ohm
2. check for short in PR122 i got 20.1ohm
3. im check for short to gnd on PQ23 pin 5 also i got 20.5ohm

be carefull. i telling you 0.5v (500mV) i've got bad experience cause too high inject voltage more than 1.0v. you look pq26 its for vcc_core. you know voltage for cpu core just 1.0V.

look like still shorted in this rail. once again no high than 1.0v, more safely if just reach 0.8v

did you test pq26 shorted after you pull out?

[bicalov]

Re: Acer aspire 4349 shorted

i may to try with 15v on leg 5 PQ23

I also was instructed by Atsio not to exceed the original voltage, go a little lower and raise the current little by little.

Follow Meritosari, he is explaining you good.
I will follow the procedures closely, but it is your thread.

[dellxps15]

Re: Acer aspire 4349 shorted

that's not the way to spot a short.

if pq23 is getting hot, remove it and with multimeter in diode mode, check wich side is shorted. i say that because on pin 5 of pq23 u have the VIN rail, and if that is the one shorted, u have to remove all vin unductors that supply all chip.

i repeat, for short dont use lab psu (u can burn a caps and damage board, u can burn caps not visible and u will never know wich one it was). use the normal one component at time remove and use brain to localize it.

i did that practice with an acer and was able to remove short and fully fix the board with a short on the +vin 19volt rail. it was a 0805 caps. replaced it and all was ok.

[bicalov]

Re: Acer aspire 4349 shorted

Now a newbe is completely knocked of his socks

[sasser]

Re: Acer aspire 4349 shorted

I agree with you , last experience with acer almost short with 0805 caps. Now im still localize which make shorten. Any update i will tell here. Fyi im use psu lab with 5v and im already try to remove 0805 caps around pq23 but still no clue.

that's not the way to spot a short.

if pq23 is getting hot, remove it and with multimeter in diode mode, check wich side is shorted. i say that because on pin 5 of pq23 u have the VIN rail, and if that is the one shorted, u have to remove all vin unductors that supply all chip.

i repeat, for short dont use lab psu (u can burn a caps and damage board, u can burn caps not visible and u will never know wich one it was). use the normal one component at time remove and use brain to localize it.

i did that practice with an acer and was able to remove short and fully fix the board with a short on the +vin 19volt rail. it was a 0805 caps. replaced it and all was ok.

[dellxps15]

Re: Acer aspire 4349 shorted

wich pin of pq23 is shorted after removing it ?

[sasser]

Re: Acer aspire 4349 shorted

wich pin of pq23 is shorted after removing it ?

pin 5

[sasser]

Re: Acer aspire 4349 shorted

update after inject power apply pq26 is shorted. now im remove and no short. without pq26 and i place back pq23 the was no short and ampere increase 0.6600A with stabile 19v.


*next i need to replace pq26 (AON6414AL) also PQ23(AOL1413).

[sasser]

Re: Acer aspire 4349 shorted

be carefull. i telling you 0.5v (500mV) i've got bad experience cause too high inject voltage more than 1.0v. you look pq26 its for vcc_core. you know voltage for cpu core just 1.0V.

look like still shorted in this rail. once again no high than 1.0v, more safely if just reach 0.8v

did you test pq26 shorted after you pull out?

meritosari i didnt found any shorted component after pull out pq26

[sasser]

Re: Acer aspire 4349 shorted

yes finally im solved the problem. the shorted component is PQ26 its not pq23. now the display is come into normal.

what i do
1. place back PQ23
2. replace Pq26 with AO4406 same channel (not sure for compabality)
3. its not any brown cap always i has seen before, its upper mosfet line 19v rail

thanks to all together help me.

[brotherCPScom]

Re: Acer aspire 4349 shorted

where to find power pins injek component hot, pin 5 or 1?