No power to KBC after chip change

[p1muserfan]

I've got no power TO the KBC chip after replacement, nothing at the 5 power-in pins. Backing up a bit, there is nothing at the resistor before the capacitors leading to the power pins either. Do have 3v at bios chip and 3v from power button at KBC though. Also have 3.3 and 5v from TPS51123

[p1muserfan]

Re: No power to KBC after chip change

Anybody?

[meritosari]

Re: No power to KBC after chip change

check if there is a short-circuit

[khaahk]

Re: No power to KBC after chip change

You have to look at Q2703 and Q2705. Why did you change the EC first place? With only battery connected the same thing?
Check the pictures at this page, was the machine with water damage?
http://notebook1.ru/forma1/viewtopic...=93849&start=0

[fddizon]

Re: No power to KBC after chip change

did you remove cmos battery before removing chip?

[p1muserfan]

Re: No power to KBC after chip change

did you remove cmos battery before removing chip?

No Is it trashed?

[Agent24]

Re: No power to KBC after chip change

It might be, I'm not sure. But it's not a good idea to replace things with the power on.

[p1muserfan]

Re: No power to KBC after chip change

You have to look at Q2703 and Q2705. Why did you change the EC first place? With only battery connected the same thing?
Check the pictures at this page, was the machine with water damage?
http://notebook1.ru/forma1/viewtopic...=93849&start=0

I've got 3v at 2 out the 3 legs of Q2703 and 3v at the drain of 2705. I changed the EC because the only way the board would start previously was to remove and then reinsert the cmos battery, mistakenly thought that would fix the problem. Now would kill to go back in time, lol. No water damage either.

[hazardus]

Re: No power to KBC after chip change

Remove the cmos battery and short all the pins on EC.

[khaahk]

Re: No power to KBC after chip change

Double check ec pins for connection or bridges.
See if pin 74 on EC is connected to q2705 gate?
Try to pull the gate of q2703 to gnd, that should provide 3v to ec.

[Ramee]

Re: No power to KBC after chip change

(khaahk is right) KBC is not sittin well check all pins.

[highpulse]

Re: No power to KBC after chip change

yes could be not been sitted , chek with a metal pick and pass on all pins , if any move , then resolder again .. i must post a video of how i solder the te KBC's but dont have a good camera and a tripe to do it .

[p1muserfan]

Re: No power to KBC after chip change

Removed the chip and when I flipped it over I have a bunch of solder bridges between many of the pins. Not sure how I'm gonna clean them up but will report back when I do and resolder chip

[ktmmotocross]

Re: No power to KBC after chip change

prefect video how to solder chips. kbc is soldered by drag soldering from 2:00

https://www.youtube.com/watch?v=5uiroWBkdFY

[p1muserfan]

Re: No power to KBC after chip change

Probably a no-no, but even with chip removed there is no power on either side of R2771 (p. 27 upper left)

[p1muserfan]

Re: No power to KBC after chip change

prefect video how to solder chips. kbc is soldered by drag soldering from 2:00

https://www.youtube.com/watch?v=5uiroWBkdFY

Nice!!

[p1muserfan]

Re: No power to KBC after chip change

Try to pull the gate of q2703 to gnd, that should provide 3v to ec.

Grounding gate of Q2703 did give me 3v to drain and therefore power to the KBC. So what is messed up and causing 3v to go to gate of 2703?

[khaahk]

Re: No power to KBC after chip change

See if pin 74 on EC is connected to q2705 gate?

[p1muserfan]

Re: No power to KBC after chip change

See if pin 74 on EC is connected to q2705 gate?

Yes, with chip off the board I have continuity between 74 and gate of Q2705

[khaahk]

Re: No power to KBC after chip change

BQ24707 pin 5 and pin 6 voltages? I think that AC_IN# if pulled low by BQ24707 pin 5, should also pull low the KBC_ON# signal through D2703 opening Q2703.