How does a KBC normally get its power?

[Bisketti]

Re: How does a KBC normally get its power?

Furthermore (as I say it depends on design), If you have power on SIO it doesn't mean that 3.3 and 5v regulator is O.K., i.e. a lot of designs they use the REG3 (LDO) pin to power SIO and then they get an EN signal to raise 3.3 and 5v.

Yes that is correct except the Sio used the 3.3v ALWS voltage the En signal is used to switch the 3.3v and 5v regulator on but this regulator should alws output the 3.3v Alws without sio/southbridge/Pch intervention.So you need to be at least getting the 3.3v voltage to sio and powerbutton for laptop to start after that is a different story. And as for the s5_enable I have never came across this signal being ALws on this usually comes after pressing power button I have observed this many times, but it may also be a design specific thing.

[lezsimply]

Re: How does a KBC normally get its power?

I'm learning from this. If so, s5_enable should have voltage before not after you press power button? and after that rsmrst should have voltage too? what is the purpose of the hash (#) sign after the name. for example RSMRST#

[Bisketti]

Re: How does a KBC normally get its power?

I'm learning from this. If so, s5_enable should have voltage before not after you press power button? and after that rsmrst should have voltage too? what is the purpose of the hash (#) sign after the name. for example RSMRST#

Well in my opinion which is by no means extensive S5_enable or whatever the vendor calls it on their board comes after you press the powerbutton it might be different on newer machines Im not 100% sure. as for the #sign I have no idea what that means

[MDY]

Re: How does a KBC normally get its power?

if you press the powerbutton and the sio does not output 3v from the RSMrst# pin the more than likely is a bad bios chip or bad flash or bad KBC.

Agree with that. Very interesting discution!

Whata does mean RSMrst# ? master reset?

[khaahk]

Re: How does a KBC normally get its power?

I'm learning from this. If so, s5_enable should have voltage before not after you press power button? and after that rsmrst should have voltage too? what is the purpose of the hash (#) sign after the name. for example RSMRST#

# - means the signal is active when in low state.
RSMRST# - reset gets delivered when state is low (0V)
the same with PWRBTN# - the button pressed signal is transferred with low voltage

[orientalsniper]

Re: How does a KBC normally get its power?

# - means the signal is active when in low state.
RSMRST# - reset gets delivered when state is low (0V)
the same with PWRBTN# - the button pressed signal is transferred with low voltage

What khaahk said, I was researching about my problem, I came across this: http://www.reballing.es/viewtopic.ph...f736531661604f

# signal gets activated in low state.

Whata does mean RSMrst# ? master reset?

I thought it meant RESUMERESET.

[nacer8]

Re: How does a KBC normally get its power?

perhaps this sequence can help.

[orientalsniper]

Re: How does a KBC normally get its power?

Alright, back to my problem, I finally soldered the pins that weren't with the help of continuity in my multimeter, but I still can't turn it on.

BIOS is desoldered, with readings in pins:

1:0
2:3.2
3:3.2
4:0
5:0
6:0
7:3.2
8:3.2

[Bisketti]

Re: How does a KBC normally get its power?

Look you should fault find systematically and not just change out components as this can introduce more issues. 1. Do you have supply to the Kbc?. 2 Can you reflash the bios out of circuit with a programmer. 3. have you checked the powerbutton is actually working?.
Are there any Leds on? and also have you identified the powerbutton pin on the kbc and checked its going to 0v when the powerbutton is pressed. Have you identified the #rsmrst pin on the kbc and checked its going to 3v when the power button is pressed?

[MDY]

Re: How does a KBC normally get its power?

What does mean if KBC RSMRST# goes to 3V after pressing power button but S5 stay at 0V? KBC, Bios, Southbridge?

[nacer8]

Re: How does a KBC normally get its power?

The transition low to high of RSMRST is the reset of Southbridge witch return two signals SIO_SLP_S5# and SIO_SLP_S3# to the KBC, then the KBC output SUS_ON signal…

[atsio]

Re: How does a KBC normally get its power?

RSMRST# or DNBSWON# (whatever the design) means (and all signals that they have the # after them) enable when low. SIO sends low signal to South and South responds with SLP_S4, SLP_S5, SLP_S3, SUSC, SUSB (whatever the design) and then SIO sends SUSON signal to all voltage regulators.

So if RSMRST# does not go low when you press the power button something wrong with SIO - BIOS

[orientalsniper]

Re: How does a KBC normally get its power?

Look you should fault find systematically and not just change out components as this can introduce more issues. 1. Do you have supply to the Kbc?. 2 Can you reflash the bios out of circuit with a programmer. 3. have you checked the powerbutton is actually working?.
Are there any Leds on? and also have you identified the powerbutton pin on the kbc and checked its going to 0v when the powerbutton is pressed. Have you identified the #rsmrst pin on the kbc and checked its going to 3v when the power button is pressed?

1) What pins supply power to KBC?
2) I have external BIOS programmer.
3) Power button works.

All LED lights were off, but I used continuity test and found some pins were not soldered, now the laptop turns ON with fan running as soon as I connect power adapter and POWER LED + Wireless LED are on.

I have not identified powerbutton or RSMRST pin in KBC yet.

This happened with old and new KBC (SIO) chips.

[nacer8]

Re: How does a KBC normally get its power?

When you release the power button, RSMRST# fall down briefly and return to high state... you should take a great attention to detect that with a DMM...

[orientalsniper]

Re: How does a KBC normally get its power?

If I'm not wrong pin #112 is RSMRST# according to attached schematic, it remains 3.3V even after pressing PWRBTN.

I've got new symptoms: It seems to be normal now when I plug power adapter, Power LED only turns on after pressing power button, however I have no video signal and when I hold power button for 4 seconds, motherboard does not power off and all the LED's blink once, then POWER and Wireless LED's are on.

EDIT: And of course the old symptoms is back if I take out CMOS battery, motherboard powers on by itself as soon power adapter is connected.

[nacer8]

Re: How does a KBC normally get its power?

It is normal for some laptop that if you take out CMOS battery, motherboard powers on by itself as soon power adapter is connected.
Attention to the microcontroller, the same reference does not mean the same input output, it is better from the chipset datasheet to identify signals.
What motherboard you have?

[orientalsniper]

Re: How does a KBC normally get its power?

It's a K43SD 2.2.

[nacer8]

Re: How does a KBC normally get its power?

see if this schematic is similar ?
Not the same EC but at the end of schematic, there is an power sequence diagram

[nacer8]

Re: How does a KBC normally get its power?

Perhaps you can foun some information...
http://*******/viewtopic.php?f=40&t=11322

[orientalsniper]

Re: How does a KBC normally get its power?

Case solved, it was just desoldered pins in KBC, with magnifying lense and light I successfully did it.

But I have to note, I didn't get 3.3V in all cases, some of them went as low as 3.0V like the power button.