Asus R702UA dead (missing voltage)

[alderick]

Re: Asus R702UA dead (missing voltage)

14 3.3V
21 3.3V
56 3.3V
85 3.3V
97 3.3V
108 0V
110 3.3V (it goes to 0V when I press power button )

Bios ic pins to GND are all out of range except the pin 8 45kohm.
Don't understand the last part of your message.

[Techtiger]

Re: Asus R702UA dead (missing voltage)

14 3.3V
21 3.3V
56 3.3V
85 3.3V
97 3.3V
108 0V
110 3.3V (it goes to 0V when I press power button )

Bios ic pins to GND are all out of range except the pin 8 45kohm.
Don't understand the last part of your message.

can you check again if pin 96 goes to 0V & come back & test Ohms on that pin 108 is connected to 10K R test voltage other side.

UP LODE A PIC near BIOS IC

what is the voltage on pin 111 on SIO this pin actives +3VA that you have marked (coil left red 3.32V) to +3VSUS & +3VA ECO

[alderick]

Re: Asus R702UA dead (missing voltage)

96 stay 3.3V, doesn't go to 0V when I press power.

pin 108 isn't connected to a resistor, the trace go on the other side of the board and there is nothing backside.

111 is 3.3V

[Techtiger]

Re: Asus R702UA dead (missing voltage)

can you test RTC diode 3.3V_RTC_ & RTC_RST# cleair this part first & find out PU8803 may be your MB not the same number check pin 8 9 13 14

[alderick]

Re: Asus R702UA dead (missing voltage)

How can I find that without the boardview? Can i go back from some component to find it?

[alderick]

Re: Asus R702UA dead (missing voltage)

I think I've found the PU8803 equivalent IC on my board, it's 548 ti 928, 14pins, and I have 3.3V on 8 9 13 and 14.

Still searching for the RTC diode

edit : I did test all schottky diode marked 42t and 43t, none are shorted or cut, but still no idea which one is RTC

[Techtiger]

Re: Asus R702UA dead (missing voltage)

do you have another BIOS chip to replace & try ? what is the voltage on bios chip except pin 4 & 8 as you power the MB

[alderick]

Re: Asus R702UA dead (missing voltage)

No, I don't, but I can order if you think it's a possible fix.

edit: I have 3.3V on all pins except the pin4 obviously.

[Techtiger]

Re: Asus R702UA dead (missing voltage)

No, I don't, but I can order if you think it's a possible fix.

edit: I have 3.3V on all pins except the pin4 obviously.

test one by on except GND when press PWRBTN for any changes with multimeter
i am not sure if you order it will work it could be PCH or SIO also,

there is a crystal in the MB near SOC CPU X2401 you have 2 caps or resistor what is the voltage on side GND other voltage may be 0.6xx,
after find out +12VS & +12SUS +5VS +5SUS are ok
do you have a heat gun ?

[alderick]

Re: Asus R702UA dead (missing voltage)

On bios chip, all pins except 4 and 8 are stable 3.31V pressing power or not doesn't change anything. Pin 8 is 3.27V stable too.

Pic related for the crystal, two caps and one resistor I guess, they are sometimes 0.28V, sometimes 0.22V

There is no 12V on the board, don't know the differences between +5VS and +5SUS but I have 5V on coil.

And yes, I have heat gun.

[Techtiger]

Re: Asus R702UA dead (missing voltage)

On bios chip, all pins except 4 and 8 are stable 3.31V pressing power or not doesn't change anything. Pin 8 is 3.27V stable too.

Pic related for the crystal, two caps and one resistor I guess, they are sometimes 0.28V, sometimes 0.22V

There is no 12V on the board, don't know the differences between +5VS and +5SUS but I have 5V on coil.

And yes, I have heat gun.

if the BIOS DATA error RSMRST will not go high , discharge the SIO remove all power take a wire 1 point to GND other to all pins take a round after take the geat gun heat up not too much all pins of SIO after slightly heat up PCH side small dice on the SIO CPU find out a working BIOS bin file how did you flash BIOS ?

[alderick]

Re: Asus R702UA dead (missing voltage)

if the BIOS DATA error RSMRST will not go high

I don't know, how can I tes that?

find out a working BIOS bin file how did you flash BIOS ?

I tried many bios myself, and some they give me here in request section.
I use a TL866 II plus with a clip, but since it's shit, I remove the chip from the board and program it on a socket.


For the thing with the heat I'll try later.

Thanks for your patience.

Edit: The laptop can work without main battery or not? Since the main battery is dead I can't test with a working battery and on that kind of cheap laptop there is no RTC battery like in the past.

[alderick]

Re: Asus R702UA dead (missing voltage)

I was checking something with the dead battery, when I bring 12V with my PSU on battery + when it's plugged on MB, the 12V goes on the main power rail, on all the board, but 0V on all coil. Is it something logical to you?

[alderick]

Re: Asus R702UA dead (missing voltage)

Hi there,

I have the hot air station now, which temp should I use? 350°C ?
What do you think about my last post?

thanks

[Techtiger]

Re: Asus R702UA dead (missing voltage)

Hi there,

I have the hot air station now, which temp should I use? 350°C ?
What do you think about my last post?

thanks

any good news did you manage to repair the MB

[alderick]

Re: Asus R702UA dead (missing voltage)

Nothing unfortunatly, it's a dead end I guess :'(

[Techtiger]

Re: Asus R702UA dead (missing voltage)

Nothing unfortunatly, it's a dead end I guess :'(

can a another Badcaps Veteran could HELP ?

[alderick]

Re: Asus R702UA dead (missing voltage)

Here is the pic of the IC we spoke in #26

[alderick]

Re: Asus R702UA dead (missing voltage)

Problem found, here the thing:

check the bordview i have send find out RTC_RST# near the SOC CPU with bios battrey in & no power adapter

I think I found the RTC_RST#, it's 0.5V with power adapter alone, battery alone, and both power adapter + battery. It seems correct to you?

no it's not correct you test it with out adapter ? only BIOS battery insert ?
check the value of the resistor its 20K RTC_RST after
check the cap one side is GND in diode mode above 2 with out any power no BIOS battery also
just next to it you have +3VA RTC one cap what's the voltage is it 3.3V ?
find out the DIODE connected to +3VA RTC what is the voltage on 3pins with power BIOS battery and adapter ?

The resistor is 12K
The cap in diode mode gave me 0.8 and 1.6 in reverse
The next cap is 2.97V
I check the diode for 30min, i'm pretty sure there is no such diode on this board, I did test all and nothing beep with my +3VA RTC net
for the BIOS battery you mean CR2032 lithium? because the laptop doesn't have it, new design without it.

CR2032 lithium Yep so it's not include in this MB can you confirm the voltage on JRST2402 & the resister voltage if it's not 3V ,
with out adapter power apply 1V on the JRST2402( not the GND) & touch near the cap & resister to see if any component worm up & check if the DC reading giving short ,
if every thing ok put a jumper from that cap with 3V to the resistor & power up the MB

JRST2402 is 0.6V
The resistor is 0.6V on one side, 2.97V on the other side.
There is no short with my psu and 1V so i put jumper like you said and IT WORKS OMG
You are genius, thank you very much.
Should I replace that resistor or leave it jumped?

great job, you must replace it 20K is to proction the PCH side

Big thanks to techtiger and all people on this wonderfull forum.

[Techtiger]

Re: Asus R702UA dead (missing voltage)

Problem found, here the thing:















Big thanks to techtiger and all people on this wonderfull forum.