Dell E5440 completely dead, no LED.

[Andreasbest]

Hello!
I have a Dell Latitude E5440 on bench that is completely dead, no led, no other activity like there is no power adapter connected.
The power_jack_in has voltage 19,5V, the PL4 has 19,5 in both sides and the PQ 4 has 19,5 Voltages too except the pin 4 that has 9,37v.
Any advice?
Thank you in advance!

schematic: https://drive.google.com/file/d/0B6I...tOR2VoV3M/view

[piernov]

Re: Dell E5440 completely dead, no LED.

Everything is fine there, you have to check further down. The main power rail +PWR_SRC_AC, the 3V and 5V power rails, etc…

[Andreasbest]

Re: Dell E5440 completely dead, no LED.

PL400 that is on PWR_SRC_AC rail has 19.5v in both pins so i guess PWR_SRC_AC is fine?
I don't know about 5v and 3v rails, can you help me locate them?
Thank you very much!

[piernov]

Re: Dell E5440 completely dead, no LED.

Sorry I wanted to say "+PWR_SRC", on PL401 for example.
The 3V/5V power rails are on page 52:
+3.3V_RTC_LDO
+5V_ALW2
+3.3V_ALW
+5V_ALW

[Andreasbest]

Re: Dell E5440 completely dead, no LED.

PL301 has 17V in one side and 0v on the other
No 3.3V in pin 3 and pin 7 of PU51
No 5v in pin 13 in PU51

[Andreasbest]

Re: Dell E5440 completely dead, no LED.

*Correction PL301 has 17V in both sides
Pin 7 of PU51 has 0,25V

[Techtiger]

Re: Dell E5440 completely dead, no LED.

Check TPS51125 pin 12 VIN pin6 EN2 pin20 En1

[Techtiger]

Re: Dell E5440 completely dead, no LED.

Find out also if the PS_ID is ok

[Andreasbest]

Re: Dell E5440 completely dead, no LED.

Pin 6 = 0.14v
Pin 12= 17.27v
Pin 20 = 0.12v

I don't think there is a problem with PS_ID as in this case the laptop power on but doesn't charge, in my case the laptop is completely and absolutely dead, no sign of life at all.

[Techtiger]

Re: Dell E5440 completely dead, no LED.

Page 52 it’s the 5/3V regulator IC

[Andreasbest]

Re: Dell E5440 completely dead, no LED.

Yup got it, search didn't return result so i looked for it manually.
Check the voltages i posted.

[Andreasbest]

Re: Dell E5440 completely dead, no LED.

can someone help me please?

[Techtiger]

Re: Dell E5440 completely dead, no LED.

Pin 6 = 0.14v
Pin 12= 17.27v
Pin 20 = 0.12v

I don't think there is a problem with PS_ID as in this case the laptop power on but doesn't charge, in my case the laptop is completely and absolutely dead, no sign of life at all.

The voltage of pin 12=17.27V this was taken with Battery ? You have to change PU51 if it's not outputting LDO 3/5 pin13 & 3 test the resistance to GND on those pins

[Techtiger]

Re: Dell E5440 completely dead, no LED.

Pin 6/20 should be around +3V to PMW to function

[Andreasbest]

Re: Dell E5440 completely dead, no LED.

No battery on, only charger and nothing else.
What do you thing?

[Techtiger]

Re: Dell E5440 completely dead, no LED.

No battery on, only charger and nothing else.
What do you thing?

+pwr_src 17V means PQ400 is not switching on check Voltage on pin 5 and 123

[Andreasbest]

Re: Dell E5440 completely dead, no LED.

Pin 1 19v
Pin 2 19v
Pin 3 19v
Pin 5 19,6v

[Andreasbest]

Re: Dell E5440 completely dead, no LED.

Any advice?

[mcplslg123]

Re: Dell E5440 completely dead, no LED.

+DC1_PWR_SRC is the rail name which goes as VIN on Pin12 of PU51 which you have measured at 17V. It should be stable 19V. Check PL51 for corrosion or PQ51 pin5 voltage.

[Andreasbest]

Re: Dell E5440 completely dead, no LED.

Hello and thank you very much for helping me!
PQ51 pin 5 = 17V
PL51 = 17v in both pins.
No corrotion, do you want to remove it and measure again?