Lenovo L420 no power only led battery blink 3 times

[lepak06]

Hello,

I ve 2 Lenovo L420 with no power only led battery blink 3 times when plug charger

I check voltage on motherboard.

I found 3VPCU and 5VPCU
I found 5V_S5 (few second after press power button) , 3VSUS (always),3V_S5(always)
BIOS IC i found 3,3V only after press button few second.
I tried flash bios

Didnt find voltage of CPU, of DDR, ...


thx

[Techtiger]

Re: Lenovo L420 no power only led battery blink 3 times

(BIOS IC i found 3,3V only after press button few second)
you should get 3.3V on pin 3 and 8 with out pressing the power button

voltages on all colis Pl15 Pl12 ect

[lepak06]

Re: Lenovo L420 no power only led battery blink 3 times

No 3,3V on Bios ic U9600 without press power button
but on the bios IC 512ko U21 i found 3,3V on pin 3 and pin 8

Voltage only on coil PL19 PL20
All the other coil are 0V with press button and without press power button

[Techtiger]

Re: Lenovo L420 no power only led battery blink 3 times

page 42 U37 PCH Bios chip flash this bios chip 4MB with this bios

https://www.badcaps.net/forum/showth...ht=Lenovo+L420

dod you get 3.3V in power button ?

(there is no Bios ic U9600)

[lepak06]

Re: Lenovo L420 no power only led battery blink 3 times

when i read the U9006 i found a similary dump.
The U9006 is an 25Q32 winbond. I didn't find on motherboard U37 at te page 42.


i ve 3,3v at the power button.

[Techtiger]

Re: Lenovo L420 no power only led battery blink 3 times

ok Schematic you have upload is for L412 not for L420 near the PCH you have another bios chip send close up snaps of the MOB both sides
test you power button when you press it goes to 0V

[lepak06]

Re: Lenovo L420 no power only led battery blink 3 times

The motherboard is DAGC9EMB8E0 rev:e, i found only the L412 schematic

When i press power button the voltage from 3.3v to 0V

[Techtiger]

Re: Lenovo L420 no power only led battery blink 3 times

remove that part

[lepak06]

Re: Lenovo L420 no power only led battery blink 3 times

I checked voltage of KBC IC but i didn't find the 3V at C134

[Techtiger]

Re: Lenovo L420 no power only led battery blink 3 times

since i don't have the Schematic i cannot tell you exact KBC number if it's IT8502E you have to test pin 26 50 92 114 121 any of the pin have 3.3V KBC power ok but in KBC a lot of test point's to check. You have programmer U21 512ko? Tell me the number 2en BIOS chip

[lepak06]

Re: Lenovo L420 no power only led battery blink 3 times

I flashed the 2 bios ic. always the same problem
The 2th Bios ic 25q32 (4M) and the other is 25x40 (512k)

I'll check the kbc voltage.

[Techtiger]

Re: Lenovo L420 no power only led battery blink 3 times

now check if your bios working one if the KBC number is
IT8502E
pin 33 RSMRST
pin 20 ECPWROK
pin 125 NBSWON take the measurements as you press the power button

[dspok]

Re: Lenovo L420 no power only led battery blink 3 times

I flashed the 2 bios ic. always the same problem
The 2th Bios ic 25q32 (4M) and the other is 25x40 (512k)

I'll check the kbc voltage.

did you solve this problem?
I have same issue in L440 model.

[OKRPKCOMP]

Re: Lenovo L420 no power only led battery blink 3 times

I have also same problem in this model
Anybody have solved this problem????

[somnath]

Re: Lenovo L420 no power only led battery blink 3 times

rtc section is short. In my case C8364 is shorted.