Acer Aspire E5-553-T7ZR clicking and not working

[giulio93]

Hi everyone. I have this laptop that has strange behavior. When I plug in the charger (no battery) I hear a clicking. I checked the first 2 mosfs tension and at the gate of the first the tension goes up and down and so all the rest of the tension are strange. I can't find the power mangament chip on this board.. I check the coils and the first 2 mosfet. The first mosfet D-S MOhm G-S 200Kohm, the second I can't measure, the multimeter is stuck at Ohm-Kohm range without showing a number. On the back of the board I noticed 2 strange things. 1) there is a hole in the smd crystal 2) on top of the board, above the battery socket CR2032 thereis a missing component and some corrosion. I will post the pics later. Can you help me with this guys?
Thank

[mon2]

So the 2nd mosfet and/or mated leg on the PCB are suspects.

Remove all power. Meter in resistance mode. Measure the resistance to ground of each of the pins on this 2nd DCin mosfet.

We are testing if the main power rail that follows the DCin mosfets are shorted or not which is causing the charger IC to halt the driving voltage on the gate pin of this same mosfet.

What are the exact measurements (in ohms) for the mosfet?

source (1-2-3)
gate (4)
drain (5-6-7-8)

Pick any pin from the groups for a measurement. Again, no power to the board. Either meter probe color on the pin to test; other meter probe to ground (metal shield is ok on the USB connector, etc.).

Do review the charger sticky bible by piernov (see above) which highlights that often, the 2nd DCin mosfet becomes defective. Still wish to know the resistance to ground of the main power rail. The charger IC should be near by and you can trace it by following the gate pin -> resistor (2k-4k ohms) -> charger IC which may be BQ series or Intersil / Renesas = ISL. Square QFN devices.

[giulio93]

So the 2nd mosfet and/or mated leg on the PCB are suspects.

Remove all power. Meter in resistance mode. Measure the resistance to ground of each of the pins on this 2nd DCin mosfet.

We are testing if the main power rail that follows the DCin mosfets are shorted or not which is causing the charger IC to halt the driving voltage on the gate pin of this same mosfet.

What are the exact measurements (in ohms) for the mosfet?

source (1-2-3)
gate (4)
drain (5-6-7-8)

Pick any pin from the groups for a measurement. Again, no power to the board. Either meter probe color on the pin to test; other meter probe to ground (metal shield is ok on the USB connector, etc.).

Do review the charger sticky bible by piernov (see above) which highlights that often, the 2nd DCin mosfet becomes defective. Still wish to know the resistance to ground of the main power rail. The charger IC should be near by and you can trace it by following the gate pin -> resistor (2k-4k ohms) -> charger IC which may be BQ series or Intersil / Renesas = ISL. Square QFN devices.

This mosfet has a strange form factor, I can see the legs. I just see 3 solderd areas, 2 on the DC in side and one on the current sensor side. The 2 on the DC in side (and 1 mosf side) are 2 MOhm the other is 53KOhm

[mon2]

Post a close up picture of the mosfet. It will be an industry standard device and often with 8 pins as referenced above. With the shared measurements to ground, the source / drain pins are not shorted to ground.

Remove all power. Measure the resistance across the same device:

source / drain
source /gate
gate / drain

Post each measurement. Now testing if the mosfet is leaking. A low resistance across these pins may mean the part is defective. Each should be hundreds of k ohms or higher.

[giulio93]

Post a close up picture of the mosfet. It will be an industry standard device and often with 8 pins as referenced above. With the shared measurements to ground, the source / drain pins are not shorted to ground.

Remove all power. Measure the resistance across the same device:

source / drain
source /gate
gate / drain

Post each measurement. Now testing if the mosfet is leaking. A low resistance across these pins may mean the part is defective. Each should be hundreds of k ohms or higher.

Meaby it not a mosfet either.
In the meanwhile I find the BQ chip, a BQ737. Here the tension:
1) up and down from 13,5 to 17,5
2) up and down from 13,5 to 17,5
3)0
4)0,05-0,09
5)0
6)2,75
7)0,11-0,18
8)3,27
9)3,27
10)0,1
11)0,42
12)up and down from 5,2 to 8
13)up and down from 5,2 to 8
14)0
15)0
16)6,1
17)up and down from 6,4 to 8,2
18)up and down from 5,2 to 8
19)up and down from 5,2 to 6,1

[giulio93]

Post a close up picture of the mosfet. It will be an industry standard device and often with 8 pins as referenced above. With the shared measurements to ground, the source / drain pins are not shorted to ground.

Remove all power. Measure the resistance across the same device:

source / drain
source /gate
gate / drain

Post each measurement. Now testing if the mosfet is leaking. A low resistance across these pins may mean the part is defective. Each should be hundreds of k ohms or higher.

What do you think about the pics and the voltage i post? Meaby It Is a BQ faulty? But what about the clicking?

[giulio93]

Post a close up picture of the mosfet. It will be an industry standard device and often with 8 pins as referenced above. With the shared measurements to ground, the source / drain pins are not shorted to ground.

Remove all power. Measure the resistance across the same device:

source / drain
source /gate
gate / drain

Post each measurement. Now testing if the mosfet is leaking. A low resistance across these pins may mean the part is defective. Each should be hundreds of k ohms or higher.

I am looking at the schematics of the board. The gate of the first mosfet (PQ30) is the output of pin5 of the PQ1. PQ1 has this V:
1)19,2
2)up and down from 8 to 16
3)up and down from 8 to 16
4)GND
5)up and down from 0,7 to 1,6
6) up and down from 11 to 15
Here the Resistance
1) 316KOhm
2) 370 KOhm
3) 370 KOhm
4) 0
5) 43 KOhm
6) 206 KOhm
Based on the internal circuit of the schematics for this chip I don't think this behavior is normal. Can be this chip the problem?
The gate of the PD30 has something to do with the BQ24737?
Thank you

[giulio93]

Meaby it not a mosfet either.
In the meanwhile I find the BQ chip, a BQ737. Here the tension:
1) up and down from 13,5 to 17,5
2) up and down from 13,5 to 17,5
3)0
4)0,05-0,09
5)0
6)2,75
7)0,11-0,18
8)3,27
9)3,27
10)0,1
11)0,42
12)up and down from 5,2 to 8
13)up and down from 5,2 to 8
14)0
15)0
16)6,1
17)up and down from 6,4 to 8,2
18)up and down from 5,2 to 8
19)up and down from 5,2 to 6,1

20) 18,6

[giulio93]

Post a close up picture of the mosfet. It will be an industry standard device and often with 8 pins as referenced above. With the shared measurements to ground, the source / drain pins are not shorted to ground.

Remove all power. Measure the resistance across the same device:

source / drain
source /gate
gate / drain

Post each measurement. Now testing if the mosfet is leaking. A low resistance across these pins may mean the part is defective. Each should be hundreds of k ohms or higher.

I think the second component right after the 1 mosf it's a diod (PD6)

[mon2]

Correct on pd6.

ACOK is low and this is not ok. ACDET is ok but perhaps missing the pull up voltage on the pull-up resistor on ACOK. Locate this resistor and check.

[giulio93]

Correct on pd6.

ACOK is low and this is not ok. ACDET is ok but perhaps missing the pull up voltage on the pull-up resistor on ACOK. Locate this resistor and check.

PR47 has 100KOhm and 0V both sides. It is this one the resistor you ask me to check?

[mon2]

Yes. The pull-up voltage rail on this line is absent. Locate who is the source of this power rail. Could be the always on 3v3 regulator.

Remove all power. Meter in resistance mode. Measure the resistance to ground of this resistor. We are testing if the pull-up voltage rail is shorted. Of concern is that the pch (CPU) makes use of the same power rail.

[giulio93]

Yes. The pull-up voltage rail on this line is absent. Locate who is the source of this power rail. Could be the always on 3v3 regulator.

Remove all power. Meter in resistance mode. Measure the resistance to ground of this resistor. We are testing if the pull-up voltage rail is shorted. Of concern is that the pch (CPU) makes use of the same power rail.

12 KOhm and 112 KOhm on the BQ side. The source of this rail is the PU11? Here the tension on it
1)0
2)0
3)3,3
4)0
5)0
6) from 0,3 to 0,5 (up and down in loop)
7)0
8)0
9)2,27
10)0
11)0
12)from 11,8 to 17,6 (up and down in loop)
13)0
14)0
15)0
16)0
17)2,27
18)0
19) from 0,25 to 0,45 (up and down in loop)
20) from 0,3 to 0,5 (up and down in loop)

[mon2]

Go back to your DCin connector. Locate the diode right beside this part. Meter in DC volts mode.

What is the voltage to ground on this diode? Is the voltage stable? Testing if the adapter voltage is stable on the motherboard or is a part on the motherboard causing this voltage to fluctuate or power cycle.

You should have a stable adapter voltage here.

Next measure the same @ PD6 (test both sides to ground for a voltage). PD6 = diode.

Post each measurement.

[giulio93]

Go back to your DCin connector. Locate the diode right beside this part. Meter in DC volts mode.

What is the voltage to ground on this diode? Is the voltage stable? Testing if the adapter voltage is stable on the motherboard or is a part on the motherboard causing this voltage to fluctuate or power cycle.

You should have a stable adapter voltage here.

Next measure the same @ PD6 (test both sides to ground for a voltage). PD6 = diode.

Post each measurement.

On PD7 I have 19.25V stable.
On PD6 I have from 11 to 17V oscillating in each pin. But I think it is normal beacause I have the gate on PQ30 V that oscillate in the same way

[giulio93]

Go back to your DCin connector. Locate the diode right beside this part. Meter in DC volts mode.

What is the voltage to ground on this diode? Is the voltage stable? Testing if the adapter voltage is stable on the motherboard or is a part on the motherboard causing this voltage to fluctuate or power cycle.

You should have a stable adapter voltage here.

Next measure the same @ PD6 (test both sides to ground for a voltage). PD6 = diode.

Post each measurement.

The pull upped line we were talking before (the one at 0V now) should be generated from PU11, isn't it? From pin 7 of this chip. But I have 0 at this pin. Maeamby there is a problem with this chip or with some of the ENBL pin that switch it on?

[mon2]

Can you share the link to the schematic? My database has only the boardview file. Post in the schematic forum.

[giulio93]

Can you share the link to the schematic? My database has only the boardview file. Post in the schematic forum.

The schematics I'm using I find on the forum, but is not exactly for my motherboard. Can I share it here to check it?
For my problem, what's the next step?
Thank you so much