BQ735/BQ24735 on asus X455LD

[kodox]

does anyone can explain how this chip works on X455LD Rev. 2.1? ACFET & RBFET won't turned on when plugged in adapter, changed parts:
- BQ735 (BQ24735)
- ACFET Mosfet
- RBFET Mosfet
- Both mosfet on battery charging side

ACDET pin @2.87v, ACOK, ACDRV & BATDRV pin @0v. no shorted components, no blown fuses on the mainboard & no broken trace in circuit

[mcplslg123]

Re: BQ735/BQ24735 on asus X455LD

ACDET@2.87 AND ACOK@0V -Is ok as far as i understand but acdrv and batdrv @0v is wrong. ACDRV should be 19v+6v approx. So that does mean gate of acfet not opening. What about pin16(regn)?? Are you getting 6v there??

[kodox]

Re: BQ735/BQ24735 on asus X455LD

ACDET@2.87 AND ACOK@0V -Is ok as far as i understand but acdrv and batdrv @0v is wrong. ACDRV should be 19v+6v approx. So that does mean gate of acfet not opening. What about pin16(regn)?? Are you getting 6v there??

thank's for replying...
yes, pin 16 is 6v & pin 17 is 1.05v

[ktmmotocross]

Re: BQ735/BQ24735 on asus X455LD

wanna know what it do?

check datasheet

[kodox]

Re: BQ735/BQ24735 on asus X455LD

wanna know what it do?

check datasheet

i did before i open this thread, hoping the master brain power can explain better for this uneducated brain than what it said on datasheet

what i wanted to know is, when does ACFET & RBFET turned on to allow 19v to system? because i can't find the "EN" pin on this ic

[ulltrium]

Re: BQ735/BQ24735 on asus X455LD

Hi @kodox, did you figure out what was the problem? I'm having the same issue with an asus n550jv board, replaced mosfets and bq735 but still don't work.

[classicandy]

Re: BQ735/BQ24735 on asus X455LD

Hi @kodox, did you figure out what was the problem? I'm having the same issue with an asus n550jv board, replaced mosfets and bq735 but still don't work.

Check surrounding resistors around BQ735 if they read their correct values. An idea of their expected values is in the image attached.

[brew99]

Re: BQ735/BQ24735 on asus X455LD

ACOK on the BQ24735 should be active High, therefore probably at 3V.

[ronelex]

Re: BQ735/BQ24735 on asus X455LD

I can only solve this kind of issue by bypassing the mosfet, I still dont know why is that acdrive is missing

[mcoytzhi27]

Re: BQ735/BQ24735 on asus X455LD

I can only solve this kind of issue by bypassing the mosfet, I still dont know why is that acdrive is missing

you bro.. andito ka rin pala... if acdrv is missing try to replace a new one.. if not fix.. try isolate those resistor nearby..

[tujuhkalitujuh]

Re: BQ735/BQ24735 on asus X455LD

i also meet the same issue.
I found out that bad BQ735 could resulting the 19v mosfet not allowing the vin to be delivered.
change more than 1 BQ735 just to make sure the replacement is good. I managed to change twice until it worked. I threw right away the new but not good BQ, well we don't know wether the BQ we bought is good or not, new or refurbished.