DELL XPS 9530 LA-9941P no power

[MicroSMD Lab]

As the topic says, no power, no lights also. 19V present at DCIN and after the first two mosfets. 13.5V on PL203, 0V on all other large coils. I get 3.29V on the power button and EC-ON. No voltage on Pin 8 of the SPI rom. No physical damage observed. I measured some voltages around PU300



Pin 12, VIN = 13.5V

Pin 20, EN1 (5V) = 0.11V

Pin 6, EN2 (3V) = 3.18V

Pin 7, PGOOD = 0V

Pin 8, SW2 = 0V

Pin 18, SW1 = 0V

Pin 3, VREG3 = 3.29V

Pin 15, DRVL1 = 0V


As always, assistance is greatly appreciated.

[mcplslg123]

What about VREG5? Resistance to GND on VREG3/VREG5/EN1/PL300/PL301? Try replacing capacitor PC312/313 with 330uF tantalum capacitor.

[MicroSMD Lab]

Resistance to gnd on:

VREG3 - 9.6k ohm
VREG5 - 22k ohm
EN1 - OL even on the 20M ohm scale
PL300 - 43k ohm
PL301 - 14k ohm

[mcplslg123]

5V present on VREG5? The resistance readings seems ok. have you tried replacing those caps i mentioned?

[MicroSMD Lab]

5V present on VREG5. I have only been able to find 330uf 2V tantalum caps on my donor boards so I am not able to replace them yet

[MicroSMD Lab]

Finally got the tantalum caps, replaced them and no difference.

[mcplslg123]

PIN20 EN1-not correct.

[MicroSMD Lab]

This seems to be a 5V line coming directly from the EC, PR341 is just a jumper. I removed PU300 and the diode mode reading on pin 20 is 0.547. Should I replace PU300 next?

[MicroSMD Lab]

I went ahead and replaced PU300 (TPS51225C) with a TPS51285B (from an XPS 9560) and it's working now. Thanks for all your help mcplslg123

[mcplslg123]

Welcome brother.