asus k53s (motherboard k53sv rev 3)

[pippostino]

Hi everyone, I have a question to solve on an asus k53s laptop (motherboard k53sv rev 3), in essence I have about 14.4 v on the battery connector, after about 5 minutes that it is charging (measured with battery inserted). Are 14.4v normal or exaggerated? I state that I opened the PC because it did not charge the battery, I found a burnt resistance of 0.020 ohm that connected with the battery connector and which I assume is part of the charging circuit. The IC of the circuit is the BQ24740. I can't find the PC service manual. Now I wonder how can the correct functioning of the charging circuit be verified and also without battery? It's possible? Another detail that I noticed is that the charge indicator LED is always orange and never green and then goes off after about 30 minutes, every now and then it flashes briefly and after 1 hour it switches off completely; the voltage measured on the battery is 12.19 volts. The charge indicator icon says to replace the battery. I apologize for taking a little longer. I attach the photo of the circuit where I replaced the resistance. Thank you !
Ps: I'm afraid to put a new battery, I wouldn't want to ruin it!

[Techtiger]

Re: asus k53s (motherboard k53sv rev 3)

Hi everyone, I have a question to solve on an asus k53s laptop (motherboard k53sv rev 3), in essence I have about 14.4 v on the battery connector, after about 5 minutes that it is charging (measured with battery inserted). Are 14.4v normal or exaggerated? I state that I opened the PC because it did not charge the battery, I found a burnt resistance of 0.020 ohm that connected with the battery connector and which I assume is part of the charging circuit. The IC of the circuit is the BQ24740. I can't find the PC service manual. Now I wonder how can the correct functioning of the charging circuit be verified and also without battery? It's possible? Another detail that I noticed is that the charge indicator LED is always orange and never green and then goes off after about 30 minutes, every now and then it flashes briefly and after 1 hour it switches off completely; the voltage measured on the battery is 12.19 volts. The charge indicator icon says to replace the battery. I apologize for taking a little longer. I attach the photo of the circuit where I replaced the resistance. Thank you !
Ps: I'm afraid to put a new battery, I wouldn't want to ruin it!

That Resistor is not burned it’s a CLR current limited Resistor that is not your problem what is the Voltage you get in Battery connector all pins with battery with out Battery

[pippostino]

Re: asus k53s (motherboard k53sv rev 3)

Hi techtiger, thanks for the prompt reply, then, first of all, the limiting resistor was burnt and I replaced it; without battery pack I have no voltage, with battery pack, the voltage varies from a minimum of 12v to 14.5v and at that point also stops the charge of the pc but the battery does not fully charge. the question I ask myself is this: is it normal for the voltage to rise to that value? shouldn't it be limited to 12.6v? another detail is that the charging indicator goes impulsively, that is, it turns on and off, it does not always stay on, consequently the LED is on, there is voltage, the LED is off, there is the residual battery voltage (about 30% of the total voltage). thanks again and good day.
forgive my english now i am using google translator

[pippostino]

Re: asus k53s (motherboard k53sv rev 3)

the battery connector has 9 pins, starting from the negative side, the first two are the negative, on the next pin (let's call it 3) there are 0v, on the next (4) there are 3.24v, oscillating at 3.27v, on the next ( 5) same situation (these should be given and clocked) the next pins (6 and 7) are 0v, and on the next pins (8 and 9) there is the battery voltage: 12.19 v if it is not charging , Oscillating 14.4v [as I explained before] if it is charging. This situation is with battery connected. If there is no battery, on the connector I have the following condition:
pin 1 and 2 = 0v
pin 3 = 3.26v
pin4 and 5 = 3.29v
pin 6 and 7 = 0v
pin 8 and 9 = + 1.26v
tanks.

[pippostino]

Re: asus k53s (motherboard k53sv rev 3)

NB: Correct: pins 4 and 5 should be DATA and CLOCK

[kropotkin]

Re: asus k53s (motherboard k53sv rev 3)

If you can not find schematics - just use commonly accessible datasheet for charger
This resistor serves for current sensing of either current cunsumption by whole laptop, either for battery charging/discharging only (there are two separate).
Which way resistor was burnt - actually, it had infinite resistance? In this case breackage of this current sensing resistors causes loss of charger's functionality.

Sometimes it can go further on...

[pippostino]

Re: asus k53s (motherboard k53sv rev 3)

hi Kropotkin, what that resistor is for is known; I don't know how it burned. The resistance had infinite value, therefore completely open;

[kropotkin]

Re: asus k53s (motherboard k53sv rev 3)

Hi! If it was originally of black color, not green which is on photo now, than those black ones tempt to mecanically loose the contactof solderingto their top along one of sides. Meet such defects few times on Asus and Samsung boards.
If you know for what this resistor serves - you can imagine that upon breakage of it all the voltage of battery/adaptor will be applied to current-measuring inputs of charger. Consequencess may be different, one photo in preview post - is Asus1215b where such black schunt due to bad contact killed newly installed charger IC in already assembled device. Later on when I met such situation I've studied it under microscope - it do was the case

[kropotkin]

Re: asus k53s (motherboard k53sv rev 3)

I have few such bords, they have green resistor, probably it is not the case. Any case, "aximum difference voltage ACP–ACN, SRP–SRN, AGND–PGND –0.5 to 0.5V" - says TI datasheet. Hardly it stay alive

[pippostino]

Re: asus k53s (motherboard k53sv rev 3)

Hi, the original resistor was green. I am interested in knowing a 3 cell 10.8 / 11.1v battery, if the voltage I find is excessive or it should be maximum 12.6V. thanks and how to check the operation without battery .thanks . original battery is A32-K53.

[kropotkin]

Re: asus k53s (motherboard k53sv rev 3)

I can not clearly understand which kind of problem do you have at the moment. Use AIDA software, there you can see some numbers of power, measured with charger for accu charging rate and battary state. Give them to us.
My suggestion - if something is wrong with indication/charging - you will deal with partially defective bq24740 in you case, as it "eated" some voltages ~100 times higher than it shoul accept at current-measuring inputs. You have possibility to try to replace it?

[pippostino]

Re: asus k53s (motherboard k53sv rev 3)

I do not have the possibility to replace it because they are not available in Italy, they only come from the UK and China and with the current situation I am afraid that certain types of imports are blocked. however I did a test, I opened the battery pack and disconnected the positive and negative battery, I powered the PC by inserting only the electronics in the battery compartment; measuring the voltage between + and - where the battery should be connected and the voltage is actually high, there are about 18v. thank you

[kropotkin]

Re: asus k53s (motherboard k53sv rev 3)

If problem is only lack of IC - you may find it on many other boards - fromsome old HP Probook 4515, 4525, compaq 615. Think you can find easily, these boards mostly defective on AMD chips, so it's 99,99% that charger IC's will be Ok.

[pippostino]

Re: asus k53s (motherboard k53sv rev 3)

Thank you Kropotkin for the indications, but unfortunately I have nothing among the disused cards in my possession. Thanks for your time