diagrams so others can see it too
http://kythuatphancung.vn/download/sony-vaio-fe880e-foxconn-ms13-mbx149-laptop-schematics.html?dl
>LDO3 2.22v
should be 3v
>and LDO5 3.20 volts.
should be 5v
where did you measure those? after some mosfets of directly on inductors?
Max8734 ALW_PWRGD?
'Sony MBX-149 VGN-FE motherboard with GO 7600'
well, there is your problem, If you didnt measure voltages I would just said GPU needs to be replaced, but you say keyboard died first , so its something else
Have you tried to power it on with the keyboard disconnected?
Its possible that the power/volume/function buttons uses the same bus as the keyboard, and the bad keyboard are preventing it to work.
Either way, these voltage lines you've measured are unacceptable.
Did you put a proper load in your power supply adapter while measuring it? It may be providing 19v with no load, but may drop with your laptop load.
Is the MAX8734 getting hot? If it is, then something is shorting out the LDOs (they can only supply 100mA max), otherwise it could be defective or the internal reference that supplies the LDOs is - check the REF pin too (across PC301 would be a good place), there should be almost exactly 2V on it. Note that as the datasheet says, there cannot be more than 100uA drawn out of this pin or the voltage will sag.
todays measurements are with smps running (after pressing power on button, on3=on5=3v), at this point ldo3/ldo5 is using smps and can supply more current
at least we know it starts
KB3910 is responsible for run_on/run_on1 signals that turn on mosfets redistributing power around. Does KB3910 get enough voltage on its vcc? it should be connected to LDO3, does it get hot?
did things like battery charge led work after keyboard initially died? do those leds work now?
I check Those chip Pins In KB3910
Ecvcc pin no: 161.. 3.34v
Ecvcc Pin No: 16... 3.34v
and battery Charge Led and Power On led 's Working after Keyboard is dead.
at now No led's ON. No LIghts are Blinking. No Beep Sounds.
Stonent GPU usually doesnt prevent from starting, on vaio its KBC or power rails.
Stonent GPU usually doesnt prevent from starting, on vaio its KBC or power rails.
It's very common on Dell and HP.
measure everything twice, before and after pressing power button !!one7I check Those chip Pins In KB3910
Ecvcc pin no: 161.. 3.34v
Ecvcc Pin No: 16... 3.34v
pin.95?Quoteand battery Charge Led and Power On led 's Working after Keyboard is dead.
at now No led's ON. No LIghts are Blinking. No Beep Sounds.
no charging or ac led suggests EC (KB3910) not working at all now, either its not powering up due to power/bios, or its dead
oh yeah, check voltages on the bios chip, I think EC loads its own firmware from there
You might try just replacing ec outright (3-5 bucks with long shipping)
http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2047675.m570.l1313.TR0.TRC0.H0.XKB3910SFC1&_nkw=KB3910SFC1&_sacat=0
again, re measure ldo3/5 after unplugging battery and ac and without pressing power, is it still really 2v/3v? if it is and you have hotair then lift EC from the board and measure again