ASUS ROG GA502D missing 19v

[jeweemiah]

Re: ASUS ROG GA502D missing 19v

First Input mosfet:
Drain: 20v
Source: 0v
Gate: 0v

Second Input mosfet:
Source: 0v
Gate: 0v
Drain: 4.3v

Charging IC


Charging IC

PIN 1 = 4.7 V
PIN 2 = 4.7 V
PIN 3 = 0 V
PIN 4 = 0 V
PIN 5 = 1.3 V
PIN 6 = 2.4 V
PIN 7 = O V
PIN 8 = 0 V
PIN 9 = 0 V
PIN 10 = 0 V
PIN 11 = 1.6V
PIN 12 = 0 V
PIN 13 = 0 V
PIN 14 = 0 V
PIN 15 = 0 V
PIN 16 = 0 V
PIN 17 = 4.2 V
PIN 18 = O V
PIN 19 = 4.2 V
PIN 20 = 4.2 V
PIN 21 = 0 V
PIN 22 = 0 V
PIN 23 = 0 V
PIN 24 = 0 V
PIN 25 = 0 V
PIN 26 = 0 V
PIN 27 = 1.7 V
PIN 28 = 19.4 V

[mon2]

Re: ASUS ROG GA502D missing 19v

measure and post the voltage readings of EACH pin on the charger IC. List the voltage list in order so that it is easier to review.

[jeweemiah]

Re: ASUS ROG GA502D missing 19v

Sorry my bad this is the compelete one

Charging IC

PIN 1 = 4.7 V
PIN 2 = 4.7 V
PIN 3 = 0 V
PIN 4 = 0 V
PIN 5 = 1.3 V
PIN 6 = 2.4 V
PIN 7 = O V
PIN 8 = 0 V
PIN 9 = 0 V
PIN 10 = 0 V
PIN 11 = 1.6V
PIN 12 = 0 V
PIN 13 = 0 V
PIN 14 = 0 V
PIN 15 = 0 V
PIN 16 = 0 V
PIN 17 = 4.2 V
PIN 18 = O V
PIN 19 = 4.2 V
PIN 20 = 4.2 V
PIN 21 = 0 V
PIN 22 = 0 V
PIN 23 = 0 V
PIN 24 = 0 V
PIN 25 = 0 V
PIN 26 = 0 V
PIN 27 = 1.7 V

[mon2]

Re: ASUS ROG GA502D missing 19v

Has the charger IC been replaced?

If yes, apply flux and low air pressure but high heat till the ic swims onto the pcb pads.

If the IC has not been replaced, suggest to source a fresh part for this repair.

The charger IC has a fixed voltage regulator on pin #24 (REGN). See the datasheet above for full details. You have 0v on the output of this LDO, it should be ~6 volts.

[jeweemiah]

Re: ASUS ROG GA502D missing 19v

I replaced the IC and got the 6V. Here is the new measurement


PIN 1 = 4.3 V
PIN 2 = 4.3 V
PIN 3 = 0 V
PIN 4 = 0 V
PIN 5 = 5.9 V
PIN 6 = 2.7 V
PIN 7 = O V
PIN 8 = 0 V
PIN 9 = 0 V
PIN 10 = 0 V
PIN 11 = 0 V
PIN 12 = 0 V
PIN 13 = 0 V
PIN 14 = 0 V
PIN 15 = 0 V
PIN 16 = 0 V
PIN 17 = 1.2 V
PIN 18 = O V
PIN 19 = 1.2 V
PIN 20 = 1.2 V
PIN 21 = 0 V
PIN 22 = 0 V
PIN 23 = 0 V
PIN 24 = 6 V
PIN 25 = 6 V
PIN 26 = 0 V
PIN 27 = 0 V
PIN 28 = 19.4 V

Still only got 4.3v on the main power rail.

[mon2]

Re: ASUS ROG GA502D missing 19v

Pins 11 & 12 are I2C (SMBUS) lines that require a pull up resistor on each pin.

Find these resistors and post pics of them.

One side of the resistor should be to sda pin and the other side to an always on 3v3 rail.

Same for the SCL pin.

You are showing the I2C lines to be 0v so either the resistors are missing/defective or the always on rail is defective.

Find the resistors to confirm the issue.

Also, it appears that you have a battery connected?

Remove it and test only with the adapter for now.

[mcplslg123]

Re: ASUS ROG GA502D missing 19v

@mon2 When 19V is not available on CLR, How +3VLP(LDO) will generate?? So SDA/SCL will be zero.

[mon2]

Re: ASUS ROG GA502D missing 19v

Sorry - what is CLR ?

[jeweemiah]

Re: ASUS ROG GA502D missing 19v

So after replacing the IC again. I now have 20v on my power rail

But still laptop won't turn on with or without the battery connected.

What are the next steps after this then? is this a bad fault?

[mon2]

Re: ASUS ROG GA502D missing 19v

I now have 20v on my power rail

Excellent.

With the adapter connected (no battery), measure the voltages again on each pin of the charger IC. Post the readings.

[jeweemiah]

Re: ASUS ROG GA502D missing 19v

Here it is


PIN 1 = 19.6 V
PIN 2 = 19.6 V
PIN 3 = 0 V
PIN 4 = 0 V
PIN 5 = 5.9 V
PIN 6 = 2.7 V
PIN 7 = O V
PIN 8 = 0 V
PIN 9 = 0 V
PIN 10 = 0 V
PIN 11 = 0 V
PIN 12 = 0 V
PIN 13 = 0 V
PIN 14 =0V
PIN 15 = 0V
PIN 16 =0V
PIN 17 = 0.1 V
PIN 18 = O V
PIN 19 = 0 V
PIN 20 = 0.1 V
PIN 21 = 0.6 V
PIN 22 = 0 V
PIN 23 = 6 V
PIN 24 = 5.8 V
PIN 25 = 6 V
PIN 26 = 0.3 V
PIN 27 = 0.1 V
PIN 28 = 19.7 V

As for pin 11 and 12 the track goes to other parts of the board no resistor along the pins.

[mon2]

Re: ASUS ROG GA502D missing 19v

Measure the voltage on each pin of the first 2 mosfets with the adapter connected, no battery.

Post the readings.

[jeweemiah]

Re: ASUS ROG GA502D missing 19v

Here its

1st mosfet =
Drain: 20.2 V
Source: 20.1 V
Gate: 26 V

2nd mosfet =
Source: 20.1 V
Gate: 26 V
Drain: 20.1 V

[mon2]

Re: ASUS ROG GA502D missing 19v

The mosfet voltages look good and gate is the expected voltage (~DCIN+6 volts to turn on).

However, do not see the same gate voltage in your post # 31.

Can you measure each voltage on the charger IC and post the list again ?

[jeweemiah]

Re: ASUS ROG GA502D missing 19v

here you go brother

PIN 1 = 20.1 V
PIN 2 = 20.1 V
PIN 3 = 0 V
PIN 4 = 0 V
PIN 5 = 5.9 V
PIN 6 = 2.7 V
PIN 7 = O V
PIN 8 = 0 V
PIN 9 = 0 V
PIN 10 = 0 V
PIN 11 = 0 V
PIN 12 = 0 V
PIN 13 = 0 V
PIN 14 =0 V
PIN 15 = 0 V
PIN 16 =0 V
PIN 17 = 0.1 V
PIN 18 = O V
PIN 19 = 0 V
PIN 20 = 0.1 V
PIN 21 = 0.6 V
PIN 22 = 0 V
PIN 23 = 6 V
PIN 24 = 5.8 V
PIN 25 = 6 V
PIN 26 = 0.3 V
PIN 27 = 0.1 V
PIN 28 = 19.7 V

[mon2]

Re: ASUS ROG GA502D missing 19v

The new list still does not show the proper voltage for ACDRV. However, the gate voltage is correct so the charger IC is spitting out the proper boosted voltage to turn on the mosfet.

Carefully check again as the list is important for a proper review.

Specifically, you must have ACDRV pin # 4 @ 26v since this is reaching the gates of the mosfet. It is the charger IC that will take in the DCIN voltage and the boost it up to the required ~26v to turn on the N-channel mosfets.

[jeweemiah]

Re: ASUS ROG GA502D missing 19v

The track of pin#4 goes immediately inside the board

[mon2]

Re: ASUS ROG GA502D missing 19v

That is fine but when using your meter, red lead on pin # 4 of the charger IC and black lead to ground - are you able to read the same voltage as on the GATE of the mosfet ?

Just trying to establish that you are properly measuring the voltages on the charger IC.

There are many 0v readings on the charger IC and do not believe the readings are accurate.

Use the red meter directly on the pin of the charger IC - I think you should be able to find a close solder / shiny PCB pad to take these measurements.

[jeweemiah]

Re: ASUS ROG GA502D missing 19v

I resoldered again the IC appplying enough solder so it covers each pad so that my leads can have a test point directly on each side of the pin.

And now my 20v can't even get to the board. My charger goes in to protection mode when I plug it in lol.

Tried replacing the IC and still charger goes to protection mode.

So Im back to my problem at the beginning but worse

[mon2]

Re: ASUS ROG GA502D missing 19v

Apply flux onto the IC -> ample heat -> low air pressure and remove the IC.

With the charger IC removed, check the first 2 mosfets for possible defects with the resistance checks - see many earlier posts on the process.

Then use flux again + low temp solder to coat each pad of the PCB where this IC is to be soldered. Take your time and be sure to not damage the IC pads.

Then use desoldering braid to remove the excess solder off the PCB - to flatten the solder bumps as much as possible.

Then use IPA to clean up the pads and locations you have just worked.

Check the bottom side of the charger IC to be sure it is clean of any shorts.

Apply flux again and apply the charger IC back onto the board. Very little solder is required to solder down SMD parts so the 'tinning' of the solder on the IC should be enough.

If the reworked IC is not working then you probably have a short somewhere.