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Repair guides and support for the Asus line of Chromebooks.

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No voltage at battery connector charger supplying 5 v

Hi , I have an asus C423NA notebook , I am trying to determine if I have a battery , charger or other issue . When I plug the charger I get no life , have tried the usual holding power button down etc .

My voltage current meter shows the charger is supplying 5 volts , confirmed on the charge socket pins ,also have 1.8 volts on 1 pin , see photo .

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I don't seem to have any voltage at all on the battery connector which i think is strange .

Update (10/18/23)

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Update (10/19/23)

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This is the location .

Ответ на этот вопрос У меня та же проблема

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@markparnell1972 if your AC adapter supplies the proper voltage (5V is just the lowest it needs to supply) and you have no voltage on the connector, check your USB C charge controller. That is an IC on your motherboard. We would need to know the exact model number for your board as well as see your board. Of course you measured that with your battery in place and you double checked your charger or tried a different one, just to rule it out.

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Thanks for the reply , I don't have another charger to try or another laptop to try the charger on , that's why I bought the voltage current meter hoping to diagnose a bad charger issue,

I measured the voltage at the pins with the battery disconnected , the meter showed 5 volts only with the laptop assembled. .

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I found a schematic but couldn't seem to find a boardview anywhere

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@markparnell1972 Most likely it starts with 5V to increase with the feedback from the computer. Let’s see what we’ll find

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I found a shorted mosfet

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A 0.2 ohm short across these 2 points

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these are the 2 on the bottom side of the board near the power connector

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@markparnell1972 what are the numbers on it? Time to desolder those and then measure the same solder pads and see if the short is gone.

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Short is gone on the pads , numbers on the chip are GA1 HD ,

I cant seem to find any info on them .

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@markparnell1972

Don't assume that the component is faulty i.e. s/c.

Looking at p.89 (71 of 71) of the schematic there are two 10mOhm (milli Ohm) sense (fusable?)resistors and also just straight links (in an 0201 smd package) in the power-battery charger circuit alone and perhaps more in other parts of the board, I didn't look. It's a bit hard to detect the difference between 10mOhms i.e. 0.01 Ohms and a s/c i.e. 0.00 Ohms with most Ohmmeters

Without a board layout it is difficult. Maybe check out p.42 of the schematic as this is the power in from the USB port which ends up going out on the PPVAR_USB_C0_VBUS and PPVAR_USB_C1_VBUS leads to the charger circuit power mosfets seen on p.89

There are 4 input charge power mosfets all of the same type which you may be able to find on the board as hopefully they will be grouped near each other. Equally they may be located near the 45 pin charge controller chip (although I doubt you'll see the pins) which would be physically bigger that a lot of the other ICs

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@markparnell1972 post one more picture but zoom out so we can see the component location on the board. I keep thinking we can probably find a similar board essentially with the same layout and components. We just have to go through a lot of them.

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@markparnell1972

If it is pin 13 it will also be connected to pin 24 and pin 40 and the other two capacitors will test the same as the one where the short is - if it is the correct one that is. (L4101 is an inductor which would have negligible resistance so C4101 should test the same). see image red, green and blue arrows - basically all are connected to the the same point i.e. between earth and pin 13, 24, and 40

Then it could be the chip or perhaps back in the PP3300_PD_A section but I think that this is getting too involved as it could be that it is a normal condition.

You would have to lift the IC off or find it's datasheet to know whether it is that end or not and if it isn't the IC and it is back towards the PP3300_PD_A section start removing components there. Not easy without a board layout.

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I thought I had made progress, I couldn't see any real problem with the other components so I ordered the chip, now the board is taking .47 amps and I have a blinking white light, but it still will not power on.

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@markparnell1972

You may have to start following the power flow chart as seen on p.3 of the schematic.

Also disconnect the battery and check what voltage is on the battery itself, just in case it is totally discharged etc as this can sometimes cause problems in laptops as the charger cannot do both, charge a flat battery and turn on and run the laptop.

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The battery has 7.5 volts on it, Its not easy to find anything to follow the flow chart without a boardview, there is not much marked on the board I see there is a power test pad for PPVAR_VNN but I don't see it anywhere.

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I have also noticed the charger only works one way around not sure if thats normal for usb c .

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@markparnell1972

USB-C should work either way as there's no wrong way to insert it, - see p.3 of the file for the pinout. The power supply is VBUS and GND.

Asides from the D+ and D- connections, what other pins are used can vary. It doesn't have to be all of 24 of them. But whatever pin is used on the top row (A) has to have a corresponding connection on the bottom row (B) in case the plug is inserted the other way. It depends on what the maker wants the port to be able to do.

Without a board layout it would be very difficult

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