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Old 06-23-2021, 07:23 PM   #21
kalilinux25
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Default Re: Acer No power A4WAB LA-C341P REV 1.0

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Originally Posted by mon2 View Post
PR316 is bad.

Power down and check the resistance of this resistor.
I tried to check the resistor by removing it outboard I got the exact value 316k but after putting it back to the board Ive lost the 3.3v to the pin 2 of PR316

Checking the pin 10 of PU301 ilim- 0v

Last edited by kalilinux25; 06-23-2021 at 07:39 PM..
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Old 06-24-2021, 12:40 AM   #22
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Default Re: Acer No power A4WAB LA-C341P REV 1.0

Check pr317 and the cap pc320. One of these must be shunting the voltage to ground. If the ic is soldered ok and is not defective then this rail should not be zero volts.
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Old 06-24-2021, 02:58 AM   #23
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Default Re: Acer No power A4WAB LA-C341P REV 1.0

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Check pr317 and the cap pc320. One of these must be shunting the voltage to ground. If the ic is soldered ok and is not defective then this rail should not be zero volts.
Resistor shows 87 kilo ohms out of the board
the caps is not shorted
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Old 06-24-2021, 04:06 AM   #24
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Default Re: Acer No power A4WAB LA-C341P REV 1.0

Then the ic must have a short. This pin is an input and the external resistor voltage divider must present a non-zero value to denote the max amount of current for this regulator.
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Old 06-24-2021, 07:26 PM   #25
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Default Re: Acer No power A4WAB LA-C341P REV 1.0

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Then the ic must have a short. This pin is an input and the external resistor voltage divider must present a non-zero value to denote the max amount of current for this regulator.
I need to change the BQ24735RGRR ? pu301
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Old 06-24-2021, 07:42 PM   #26
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Default Re: Acer No power A4WAB LA-C341P REV 1.0

1) PR317 should be 100k 0402 1% tolerance.

2) Based on the same page in the schematic, with 100k & 316k voltage divider using +3VALW, this configures this charger IC to support 3.966A of current.

This will only occur if there is a non-zero value at the middle junction of these 2 resistors.

Currently (no pun) you have 0 volts at this common pin # 10 (ILIM).

3) Confirm that the pin #10 of PU301 is not shorting to something else under the chip. Perhaps even consider to flux and reflow this IC. Then check the voltage on this pin again.

4) Aside from the above, believe that you should consider sourcing a fresh IC and replace this PU301 and then test again.

5) As a test, you can remove PU301 but also remove PL302 and then power up and check the voltage at the pad for Pin # 10.

Based on the 2 resistor values, this pin must be a non-zero voltage value.

I would also source a 100k 0402 1% resistor to replace the 87k one on the logic board.

The reason to remove the PL302 is to prevent any voltages from being sent downstream in the absence of this PU301 IC. Thought is that PU301 is now strapping the Pin #10 to ground, either due to a solder short and internal defect.
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Old 06-24-2021, 08:31 PM   #27
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Default Re: Acer No power A4WAB LA-C341P REV 1.0

Quote:
Originally Posted by mon2 View Post
1) PR317 should be 100k 0402 1% tolerance.

2) Based on the same page in the schematic, with 100k & 316k voltage divider using +3VALW, this configures this charger IC to support 3.966A of current.

This will only occur if there is a non-zero value at the middle junction of these 2 resistors.

Currently (no pun) you have 0 volts at this common pin # 10 (ILIM).

3) Confirm that the pin #10 of PU301 is not shorting to something else under the chip. Perhaps even consider to flux and reflow this IC. Then check the voltage on this pin again.

4) Aside from the above, believe that you should consider sourcing a fresh IC and replace this PU301 and then test again.

5) As a test, you can remove PU301 but also remove PL302 and then power up and check the voltage at the pad for Pin # 10.

Based on the 2 resistor values, this pin must be a non-zero voltage value.

I would also source a 100k 0402 1% resistor to replace the 87k one on the logic board.

The reason to remove the PL302 is to prevent any voltages from being sent downstream in the absence of this PU301 IC. Thought is that PU301 is now strapping the Pin #10 to ground, either due to a solder short and internal defect.



I tried the option to remove the PU301 and the PL302

Checking voltage at

PQ302
5. 19V
1,2,3, - 0V
4 -0V

PIN 10 of pad #10 0v

maybe it has no voltage beacause it wont allow the PQ302to passs the 19v?
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Old 06-24-2021, 10:02 PM   #28
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Default Re: Acer No power A4WAB LA-C341P REV 1.0

No. If the 316k is mated to +3v3Alw which it is and the 100k is truly to ground (confirm this) then you have a resistor based voltage divider. For this reason, this cannot be 0 volts unless one of these resistors is defective or not as connected in the schematic.

Google "resistor voltage divider calculator" and punch in the 3.3 volts; 316k, 100k value to see the expected voltage value.

https://ohmslawcalculator.com/voltag...der-calculator
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Old 06-24-2021, 10:52 PM   #29
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Default Re: Acer No power A4WAB LA-C341P REV 1.0

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Originally Posted by mon2 View Post
No. If the 316k is mated to +3v3Alw which it is and the 100k is truly to ground (confirm this) then you have a resistor based voltage divider. For this reason, this cannot be 0 volts unless one of these resistors is defective or not as connected in the schematic.

Google "resistor voltage divider calculator" and punch in the 3.3 volts; 316k, 100k value to see the expected voltage value.

https://ohmslawcalculator.com/voltag...der-calculator
trying to reflow the resistors then tried a new reissitor same issue no 3.3v present
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Old 06-25-2021, 04:30 AM   #30
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Default Re: Acer No power A4WAB LA-C341P REV 1.0

Check the resistance on the 100k resistor. Is it zero ohms at the pin that mates with the 316k?

Is the other pad of the 100k really mated to ground?

Remove the cap in this area to rule out the cap as a short.
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Old 06-25-2021, 07:33 PM   #31
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Default Re: Acer No power A4WAB LA-C341P REV 1.0

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Originally Posted by mon2 View Post
Check the resistance on the 100k resistor. Is it zero ohms at the pin that mates with the 316k?

Is the other pad of the 100k really mated to ground?

Remove the cap in this area to rule out the cap as a short.
Yes everything is mated to ground the cap was remove then tried to plug power no voltage reading again to the resistors
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Old 07-23-2021, 03:31 AM   #32
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Default Re: Acer No power A4WAB LA-C341P REV 1.0

Quote:
Originally Posted by mon2 View Post
Check the resistance on the 100k resistor. Is it zero ohms at the pin that mates with the 316k?

Is the other pad of the 100k really mated to ground?

Remove the cap in this area to rule out the cap as a short.

I now tried to change thePU301 blinking LED at the power led the charging light and the blue light its taking only 6 amps unstable..


PQ302

pin 1- 0v
pin 2-4- 0v
pin 5 20v

PU301

PIN 1 -20V
PIN 2 - 20V
PIN 3 - 10-11V not stable
PIN 4 - 11, 12, 13 not stable
pin 5- 1v not stable 1.1v
pin 6 - 2.7v stable
pin 7 -0v
pin 8 - 3.3v
pin 9 - 3.3v
pin 10 - 0v
pin 11- 24v
pin 12 - 20v
pin 13 - 20v
pin 14 - 0v
pin 15 - 0v
pn 16 - 6.0v stable
PIN 17 -20V STABLE
PIN 18 - 20V STABLE
PIN 19 - 20V
PIN 20- 20V


PL402 - 3.3V
PL404 - 5V
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Old 07-23-2021, 05:25 AM   #33
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Default Re: Acer No power A4WAB LA-C341P REV 1.0

First of all, your AC power supply must be working properly. charge control voltages are in the picture. The IO needs to receive +3V LDO and AC_OK signal to work. By sending EC_ON after the IO AC_OK signal, +3v and +5v are activated. ILIM is not so important, it can be 0. If there is no short circuit in the +B19 line, the PU301 charge control voltages should be as follows.
Attached Images
File Type: jpg BQ24738.jpg (212.0 KB, 15 views)
File Type: jpg System.jpg (147.4 KB, 13 views)
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Old 07-23-2021, 08:29 PM   #34
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Default Re: Acer No power A4WAB LA-C341P REV 1.0

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Originally Posted by Sametbey View Post
First of all, your AC power supply must be working properly. charge control voltages are in the picture. The IO needs to receive +3V LDO and AC_OK signal to work. By sending EC_ON after the IO AC_OK signal, +3v and +5v are activated. ILIM is not so important, it can be 0. If there is no short circuit in the +B19 line, the PU301 charge control voltages should be as follows.
Yes but Unit still no power sir why its causing it what to test and change\
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Old 07-31-2021, 03:20 AM   #35
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Default Re: Acer No power A4WAB LA-C341P REV 1.0

Hi hope someone can help me?
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Old 07-31-2021, 08:02 AM   #36
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Default Re: Acer No power A4WAB LA-C341P REV 1.0

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Hi hope someone can help me?
SW4 BI SW .Press the switch in .
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Old 08-02-2021, 09:43 PM   #37
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Default Re: Acer No power A4WAB LA-C341P REV 1.0

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SW4 BI SW .Press the switch in .
how can I test it sir?
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Old 08-03-2021, 10:17 PM   #38
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Default Re: Acer No power A4WAB LA-C341P REV 1.0

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SW4 BI SW .Press the switch in .
I already tried the switch same issue
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Old 08-03-2021, 10:20 PM   #39
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Default Re: Acer No power A4WAB LA-C341P REV 1.0

If the board is plug without power press I only have 5V present @ PL404 I dont have 3V @ pl402 . Ive check resistance of PL402 around 3kilo ohms PL404 5KILO OHMS. If I press power it will produce a stable 3.3v and 5v but it only takes 8milliamps to 10 milliamps
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Old 08-04-2021, 01:31 AM   #40
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Default Re: Acer No power A4WAB LA-C341P REV 1.0

Quote:
Originally Posted by Sametbey View Post
First of all, your AC power supply must be working properly. charge control voltages are in the picture. The IO needs to receive +3V LDO and AC_OK signal to work. By sending EC_ON after the IO AC_OK signal, +3v and +5v are activated. ILIM is not so important, it can be 0. If there is no short circuit in the +B19 line, the PU301 charge control voltages should be as follows.
Hi sir can you send me a clear image
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