Technical Support Latitude 5480 No POST

[irepairs]

Hello, I am having issue with Latitude E5480 , all S5 voltage rails are present and correct (5V, 3.3V, 1V), there is no LED indicators stating that the motherboard, RAM or CPU have any issues. However, I tried Dell Bios Recovery Took (CTRL + ESC) it won't go to Bios Recovery Mode, I tried the LCD BIST and it passed the test. I tried the Motherboard BIST and it passed. The laptop doesn't turn on at all. What other things I can try? It just gives battery charging light when I plug the AC Charger.

 

[Ahmad Safari]

Hello
Because I use Google Translate, I did not understand your meaning very well.
Does the device turn on now or not?
Have you checked the various parts of the board?
Because sometimes a connection on the board causes the system to go into protection mode and not turn on.

 

[irepairs]

It does not turn on. The motherboard has no issues in terms of power. I am getting all voltage rails correct. I tested using Dell Motherboard Test and it did not give any beeps or lights.

 

[Ahmad Safari]

If you measured the diode resistance of different parts and it is normal, and the standby voltages are available.
To turn on the laptop, the 32 kHz crystal and EC and PCH play a fundamental role.
Hall sensor is also sometimes effective.

 

[irepairs]

I attached the voltages and resistance values.

 

[Ahmad Safari]

In ohm measurement, we measure ohms relative to ground and B+.
Compared to Grand Ohm, I think it was normal. Check for B+ as well.
Check the BIOS and health of the power button and the signals between IO and PCH from the power sequence.