Asus FX505G - no power to battery and won't turn on

[CptChronic]

Re: Asus FX505G - no power to battery and won't turn on

ACDRV is low, but not without voltage. Could point to faulty DC-IN Mosfets. Do you know howto check? Sadly we didn't this sanity measurements before...

Well that chip has definitely fixed some of it as I'm now getting voltage on the gates of those 2 mosfets and 20V is flowing through them. It wasn't before. I've traced the voltage and it stops at 2 other mosfets and turns into 0.2V on their outputs. These are located right next to the battery connection. Pics here: https://imgur.com/a/Hi0HOqw

[CptChronic]

Re: Asus FX505G - no power to battery and won't turn on

Remove the ~4k resistor that will be in series with the ACDRV pin and often is driving the gate pins of the 2 x DCin mosfets.

Do not lose the removed ~4k resistor.

Power up again. What is the voltage to ground now of the ACDRV pin?

I get 0 volts with that resistor removed

[mon2]

Re: Asus FX505G - no power to battery and won't turn on

Is the battery charged?

Remove all power from the power adapter. Use only the battery -> does the logic board power up on the battery power only?

[CptChronic]

Re: Asus FX505G - no power to battery and won't turn on

Is the battery charged?

Remove all power from the power adapter. Use only the battery -> does the logic board power up on the battery power only?

No the battery is dead unfortunately, it wasn't being charged by the circuit. I'm pretty sure it was at 10V on Friday but now it's 0V.

After refitting the resistor I'm now getting 25V on the ACDRV pin

[Sephir0th]

Re: Asus FX505G - no power to battery and won't turn on

That's perfect. Main power rail is fixed then. No need to look into the battery charging circuit without battery even present. The voltages you have measured there are useless and meaningless without battery.

You're saying it still doesn't turn on?

[CptChronic]

Re: Asus FX505G - no power to battery and won't turn on

That's perfect. Main power rail is fixed then. No need to look into the battery charging circuit without battery even present. The voltages you have measured there are useless and meaningless without battery.

You're saying it still doesn't turn on?

Brilliant.

This battery is strange, I fitted it and it started reading 9.5V, it did the same once disconnected. So I put everything back together and tried again but now the battery is back reading 0V both disconnected and connected

No it doesn't turn on either

[Sephir0th]

Re: Asus FX505G - no power to battery and won't turn on

Okay, next step would be to confirm, whether a) 20V are still present at the main power rail and b) the EC receives 3.3V from LDO Regulator. Maybe you even get 3.3V at the Power-Button right now.

[CptChronic]

Re: Asus FX505G - no power to battery and won't turn on

Okay, next step would be to confirm, whether a) 20V are still present at the main power rail and b) the EC receives 3.3V from LDO Regulator. Maybe you even get 3.3V at the Power-Button right now.

I'm getting 20V upto these mosfets here: https://imgur.com/a/Hi0HOqw it's the same with or without the battery connected.

I can't get to the button to check the voltage unfortunately, I'm guessing it is connected to one of the pins of the ribbon that comes in through the right hinge but I've no idea which. https://imgur.com/a/1ZIgJ7e

I've checked the voltage on the EC though, it's an IT8987 here's the pinout: https://imgur.com/a/juTs0Bo pin 11 is not receiving any voltage. Here's some more pictures of the surrounding area: https://imgur.com/a/T2MBpcy

Is this the LDO here? https://imgur.com/a/PfMxyn5 it's not receiving any voltage if so. Datasheet here: https://www.google.com/url?sa=t&sour...-V6P4fyzIYnwdo

[Sephir0th]

Re: Asus FX505G - no power to battery and won't turn on

I'm getting 20V upto these mosfets here: https://imgur.com/a/Hi0HOqw it's the same with or without the battery connected.

I can't get to the button to check the voltage unfortunately, I'm guessing it is connected to one of the pins of the ribbon that comes in through the right hinge but I've no idea which. https://imgur.com/a/1ZIgJ7e

I've checked the voltage on the EC though, it's an IT8987 here's the pinout: https://imgur.com/a/juTs0Bo pin 11 is not receiving any voltage. Here's some more pictures of the surrounding area: https://imgur.com/a/T2MBpcy

Is this the LDO here? https://imgur.com/a/PfMxyn5 it's not receiving any voltage if so. Datasheet here: https://www.google.com/url?sa=t&sour...-V6P4fyzIYnwdo

Almost.

The +3VA will be most likely created from the same controller who controls the buck converter for the +3VA_DSW (or however it is called here, basically the voltage at the coil) and on some ASUS devices the +3VA_EC has to be additionally enabled from a loadswitch via PS_ON signal, a switch as you showed in your pictures, thinking it is the "LDO". You might have +3VA "Input" from the controller on one side and +3VA_EC "Output" reching the embedded controller on the other side.

Staying at +3VA, simply pay attention to the EC Pins 26, 50, 92, 114, 121, 127. Do measures resistance to GND of these Pins without power afterwards

[CptChronic]

Re: Asus FX505G - no power to battery and won't turn on

Almost.

The +3VA will be most likely created from the same controller who controls the buck converter for the +3VA_DSW (or however it is called here, basically the voltage at the coil) and on some ASUS devices the +3VA_EC has to be additionally enabled from a loadswitch via PS_ON signal, a switch as you showed in your pictures, thinking it is the "LDO". You might have +3VA "Input" from the controller on one side and +3VA_EC "Output" reching the embedded controller on the other side.

Staying at +3VA, simply pay attention to the EC Pins 26, 50, 92, 114, 121, 127. Do measures resistance to GND of these Pins without power afterwards

Sorry for the delay, I had to go home last night.

So I've tested all those pins, they're all receiving 0.27V and are reading 2 Ohms each.

Guessing that's not good?

Where did you learn all this stuff if you don't mind me asking? Never would of gotten this far without you man

[Sephir0th]

Re: Asus FX505G - no power to battery and won't turn on

Youtube, Discord, Badcaps.

Yes, there is a short to GND and yes it is most likely the embedded controller. However, better to confirm by injecting 1Volts/1Ampere and see whether it will heat up. You are allowed to raise the current, if the board takes the full 1Amps and still nothing getting hot.

[CptChronic]

Re: Asus FX505G - no power to battery and won't turn on

Youtube, Discord, Badcaps.

Yes, there is a short to GND and yes it is most likely the embedded controller. However, better to confirm by injecting 1Volts/1Ampere and see whether it will heat up. You are allowed to raise the current, if the board takes the full 1Amps and still nothing getting hot.

I watch alot of Sorin and a few other guys on YouTube.

Is it a programmed EC? Or can I just swap it out for an off the shelf chip?
I hate to ask but where should I inject voltage? Better safe than sorry

[Sephir0th]

Re: Asus FX505G - no power to battery and won't turn on

I watch alot of Sorin and a few other guys on YouTube.

Is it a programmed EC? Or can I just swap it out for an off the shelf chip?
I hate to ask but where should I inject voltage? Better safe than sorry

You inject more or less at one of those pins where you have measured the 2 Ohms short before, or any connected point you can assume and verify by visual inspection/multimeter.

You might be lucky and the EC programs itself from the main BIOS flash, as on many other ASUS mobo's. But this will only work if the EC flash is "empty" and no guarantee, of course, as always.

[CptChronic]

Re: Asus FX505G - no power to battery and won't turn on

You inject more or less at one of those pins where you have measured the 2 Ohms short before, or any connected point you can assume and verify by visual inspection/multimeter.

You might be lucky and the EC programs itself from the main BIOS flash, as on many other ASUS mobo's. But this will only work if the EC flash is "empty" and no guarantee, of course, as always.

https://imgur.com/a/8Vmc0yc
It doesn't heat up excessively at 1A 1V - my power supply will only give it 0.27A though no matter what I set it to. It's rated for 10A

[Sephir0th]

Re: Asus FX505G - no power to battery and won't turn on

https://imgur.com/a/8Vmc0yc
It doesn't heat up excessively at 1A 1V - my power supply will only give it 0.27A though no matter what I set it to. It's rated for 10A

That's enough confirmation. Remove it and then measure the pads again which measured shorted before.

[CptChronic]

Re: Asus FX505G - no power to battery and won't turn on

That's enough confirmation. Remove it and then measure the pads again which measured shorted before.

Perfect, I have now removed it and the resistance rises rather than sitting at 2 Ohms. I stopped when it got to 90K.

Ill get one of these chips ordered and will update you once it arrives. Fingers crossed it programs itself like you said

Thanks again for all the help buddy!

[CptChronic]

Re: Asus FX505G - no power to battery and won't turn on

That's enough confirmation. Remove it and then measure the pads again which measured shorted before.

Got the new chip fitted today, the battery is now receiving 3.3V when plugged in and the black lit keyboard lights up but that's about it. The charging light isn't even lit up. The red output wires from the battery are still on 0.228V, I've managed to get that upto 9.XV by poking around the mosfets, I guess I turned one on by the gate but it made no difference and didn't stay that way for long.

The cpu is getting warm.

Do you think this is because the EC needs to be programmed? I've done a load of reading and watched some videos and apparently when they're new they shouldn't need to be programmed but I haven't a clue. I'm gutted, was really hopeful this was going to fix it