lenovo yoga 13 mb panasonic

[Rekoo1997]

Hello all friends.
yoga 13 mb panasonic
not working when rtc is conncected or charger connected after shutdown
in another meaning
no power if any volt in mb but led power is on and no current
but if remove rtc and battery and charger its working
i flashed bios and clear me but still proplem

[mcplslg123]

Re: lenovo yoga 13 mb panasonic

You mean mb is only working when RTC cell and adapter is removed or you mean only RTC cell is removed??

It seems you have some short on RTC section.

Measure voltage on the following points:

01.DC in mosfet pin1/4/8
02.RTCRST# & SRTCRST#

For measuring RTC voltages mb should have no power(adaper+Battery), only RTC cell inserted. make sure RTC cell is 3V.

[Rekoo1997]

Re: lenovo yoga 13 mb panasonic

You mean mb is only working when RTC cell and adapter is removed or you mean only RTC cell is removed??

It seems you have some short on RTC section.

Measure voltage on the following points:

01.DC in mosfet pin1/4/8
02.RTCRST# & SRTCRST#

For measuring RTC voltages mb should have no power(adaper+Battery), only RTC cell inserted. make sure RTC cell is 3V.

yes I mean its working only when RTC cell and adapter and battery is removed
and I don't have schematic

[mcplslg123]

Re: lenovo yoga 13 mb panasonic

Without schematic it'll be more difficult but not impossible. You need to insert RTC cell with 3V and then trace the connections to 2 resistors of 20Kohms each. There may be jumper pads on mb marked as CMOS or similar. Look for them.

You didnt answered on dc-in mosfet voltage.

[Rekoo1997]

Re: lenovo yoga 13 mb panasonic

Without schematic it'll be more difficult but not impossible. You need to insert RTC cell with 3V and then trace the connections to 2 resistors of 20Kohms each. There may be jumper pads on mb marked as CMOS or similar. Look for them.

You didnt answered on dc-in mosfet voltage.

dc in mosfet If the device is working pin1=19.3 pin 4=25 pin 8=19
dc in mosfet If the device does not work pin1=20 pin 4=26 pin 8=20
In both cases ic bios vcc 3.3v
In both cases power button =3.3v

I do the following:
flash BIOS
clear me
replace the charging ic bq735
replace ic 8150l
But the same problem
Any suggestions?

[mcplslg123]

Re: lenovo yoga 13 mb panasonic

Your dc-in fets voltage is perfect and charging IC seems to be ok. Since mb is working fine with display, i beleive you need to probe RTC circuit.

[Rekoo1997]

Re: lenovo yoga 13 mb panasonic

thank you my friend
The problem was the diode Not Found
Maybe Previous maintenance result
And I replaced
Now the device is working normally