Dell Latitude e7440 (LA-9591P) diagnostic

[ggman]

Hello Friends

I need your help in Dell Latitude e7440 (LA-9591P) diagnostic.
The issue is that laptop doesn't start if power button applied, the power LED on but than off after several seconds, no image appeared on the screen, cooling fan doesn't on.

I have checked power distribution on the motherboard:
+PWR_SRC – 13,6V
+5V_ALW – 5,1V
+3,3V_ALW – 3,3V
+3,3V_ALW_PCH – 3,3V
+3,3V_RTC_LDO – 3,3V
+3,3V_SUS – 0V
+1,35V_MEM – 0V
+5V_RUN – 0V
+3,3V_RUN – 0V
+1,05V_RUN – 0V
+VCC_CORE – 0V

Signals from UC1H (CPU):
SIO_SLP_S0 – 3,2V
SIO_SLP_S3 – 0V
SIO_SLP_S4 – 0V
SIO_SLP_S5 – 0V
SIO_SLP_A – 0V

Signals from MEC5075:
A_ON – 0V

Signals from MEC5048:
SUS_ON – 0V
RUN_ON – 0V

The problem is that I didn't find power on sequences for this motherboard.

Could you please advise power on sequences for LA-9591P.

The avlible schematic is attached.

Thank you.

[piernov]

Re: Dell Latitude e7440 (LA-9591P) diagnostic

Signals from UC1H (CPU):
SIO_SLP_S0 – 3,2V
SIO_SLP_S3 – 0V
SIO_SLP_S4 – 0V
SIO_SLP_S5 – 0V
SIO_SLP_A – 0V

100% sure about this?

[ggman]

Re: Dell Latitude e7440 (LA-9591P) diagnostic

100% sure about this?

Hello Piernov

Thank your reply

I have rechecked again signal on JAPS1 connector.

SIO_SLP_S3, SIO_SLP_S4, SIO_SLP_S5 and SIO_SLP_A always 0V. But when I checked SIO_SLP_S0 voltage at first was 0,13V, than I disconnected ground probe and connected it again the voltage inceased up to 3,13V, than I pressed power button and when power had LED off the voltage become 0,13V again, when I moved ground probe again the voltage increased.

I attached video

What do you thing, could it be cause of the issue?

Regards

[albasiba]

Re: Dell Latitude e7440 (LA-9591P) diagnostic

Hello Ggman, I have the same issue with the same laptop. Did you find any way to solve this problem?

Regards,
Ali

[stefanbs]

Re: Dell Latitude e7440 (LA-9591P) diagnostic

The SPU (SoC ) dies on these laptops, most probably this is what happened to yours.

[maki]

Re: Dell Latitude e7440 (LA-9591P) diagnostic

The SPU (SoC ) dies on these laptops, most probably this is what happened to yours.

Do you mean CPU ?

[s22o]

Re: Dell Latitude e7440 (LA-9591P) diagnostic

Disconnect +DCIN JACK. Disconnect cell 3.3v from JRTC1. Press SW1 for 20s. Connect +DCIN JACK 19.5V. Works.
Same symptoms. Tried.

[carrneiro]

Re: Dell Latitude e7440 (LA-9591P) diagnostic

Disconnect +DCIN JACK. Disconnect cell 3.3v from JRTC1. Press SW1 for 20s. Connect +DCIN JACK 19.5V. Works.
Same symptoms. Tried.

LOL