My laptop acer aspire 5720zg dead (no power and lights)

[povilas602]

Hey, i have laptop Acer Aspire 5720zg with no power and lights. Adapter is checked and getting power ~19V. No lights with adapter and battery. My laptop motherboard number ICL50 LA-3551P. Any help where to look first?

[lord]

Re: My laptop acer aspire 5720zg dead (no power and lights)

Check for power button voltage.

[povilas602]

Re: My laptop acer aspire 5720zg dead (no power and lights)

Power button voltage ~16.1 V, when I press button voltage drops to zero.

[robrock1]

Re: My laptop acer aspire 5720zg dead (no power and lights)

Check 3.3v and 5v standby voltage, see if something is getting hot

[povilas602]

Re: My laptop acer aspire 5720zg dead (no power and lights)

I mark two place where getting hot. I don't have motherboard scheme, then I can't check 3V and 5V. Can you give the address or show on the motherboard where I need to check 3V and 5V.

[lezsimply]

Re: My laptop acer aspire 5720zg dead (no power and lights)

Check PL3 for 3.3v_alw and PL4 for 5v_alw, voltages must be present.

Look for PU3 (MAX8744E) thats your 5v and 3.3v regulator IC. Schem added. hope this helps...

[povilas602]

Re: My laptop acer aspire 5720zg dead (no power and lights)

PL3 0.01 and PL4 0.07V, but for PU3 i don't understand what pin I must check for 5V and 3V...

[lord]

Re: My laptop acer aspire 5720zg dead (no power and lights)

Do you have voltage on pin 21 of PU3?

[povilas602]

Re: My laptop acer aspire 5720zg dead (no power and lights)

3.3V on pin21

[robrock1]

Re: My laptop acer aspire 5720zg dead (no power and lights)

see if any of the diodes or transistors is shorted in this area

[lord]

Re: My laptop acer aspire 5720zg dead (no power and lights)

3.3V on pin21

Are you sure?
PL2 and pin21 should be connected. You should have 19V there.

[povilas602]

Re: My laptop acer aspire 5720zg dead (no power and lights)

Now I checked PU3 PIN21 is 3.3V, but in #5 comment picture i mark two place where getting hot. Maybe PD2,PR2,PR3,PR4,PR5,PR6,PR7,PR8 in this place heat up. PL2 3.2V.

[povilas602]

Re: My laptop acer aspire 5720zg dead (no power and lights)

I found PD2 and PD3 diodes broken.

[robrock1]

Re: My laptop acer aspire 5720zg dead (no power and lights)

so its working now?

[povilas602]

Re: My laptop acer aspire 5720zg dead (no power and lights)

Does not work, when PD3 don't been soldered, then PL2 was 19.2V, but when PD3 was soldered, then PL2 fell to 3.3V. What else to check?

[povilas602]

Re: My laptop acer aspire 5720zg dead (no power and lights)

So no one can advise what to check?

[whaldsz]

Re: My laptop acer aspire 5720zg dead (no power and lights)

Check the resistance across PC6. If low resistance, remove PU2 and test again.

[djmdk]

Re: My laptop acer aspire 5720zg dead (no power and lights)

Hello,
I have the exact same problem as you do. How did you fix your motherboard? Can you please help me?
Thank you!

[djmdk]

Re: My laptop acer aspire 5720zg dead (no power and lights)

Anyone?

[mcthr]

Re: My laptop acer aspire 5720zg dead (no power and lights)

if the 3.3 volts is intermittent supply does dc to dc is faulty. im working in Acer V3 series ty dor the reply