dell inspiron N5050 3v,5v alw no present

[Yosua]

good afternoon all my colleagues, I hope that on this occasion someone can guide me to overcome this DELL INSPIRON N5050 mobo, the problem is that there is no voltage on the 3v and 5v coils, and after I saw the schematic of this mobo, it uses IC TPS51123 and I have measured the important points on this ic pin, and this is the measurement result:


VIN : 19V
VREF: 1.8V
EN0 : 1.3V
VREG3; 3V
VREG5 ; 5V
ENC: 1.3V
ENTRIP1 & 2: 0V

I've already done flash bios but it's still the same

Thank you for your attention, I also attached the schematic for this mobo

[mon2]

Re: dell inspiron N5050 3v,5v alw no present

Which IC are you referencing ? PU4103 ?

[mcplslg123]

Re: dell inspiron N5050 3v,5v alw no present

This mb has Nuvoton KBC and PSL Logic is involved here and often is the cause of no volts on 3/5V coil. I hope you can move on from this clue.Btw, is the 3/5V PWm getting Hot??

[Udemzy]

Re: dell inspiron N5050 3v,5v alw no present

Follow the PSL logic but then your ENC is generating but it is low 1.3v, after ENC is released you Will get volt on Entrip before 3.3v/5v coil will generate.

Trace back ENC pin

[lapfix]

Re: dell inspiron N5050 3v,5v alw no present

As mcplslg123 mention before take the voltages at this pins and post it here

U2701A page 27 :

PSL_IN2 pin 93
PSL_IN1 pin 73
PSL_OUT pin 74

S5_ENABLE pin 14

[Yosua]

Re: dell inspiron N5050 3v,5v alw no present

This mb has Nuvoton KBC and PSL Logic is involved here and often is the cause of no volts on 3/5V coil. I hope you can move on from this clue.Btw, is the 3/5V PWm getting Hot??

Yes sir youre right , the ic is geting hot

[Yosua]

Re: dell inspiron N5050 3v,5v alw no present

As mcplslg123 mention before take the voltages at this pins and post it here

U2701A page 27 :

PSL_IN2 pin 93
PSL_IN1 pin 73
PSL_OUT pin 74

S5_ENABLE pin 14

thank you for all the advice sir, and this is the measurement result

PSL_IN2 pin 93=0v
PSL_IN1 pin 73=0v
PSL_OUT pin 74=2.9v
S5_ENABLE pin 14=1.1v

[Yosua]

Re: dell inspiron N5050 3v,5v alw no present

Which IC are you referencing ? PU4103 ?

IC 3v and 5v sir namely TPS51123

[mcplslg123]

Re: dell inspiron N5050 3v,5v alw no present

Q2704-Voltage on all pins(located near SIO)?? Most probably its bad. Its a P channel mosfet.

[Yosua]

Re: dell inspiron N5050 3v,5v alw no present

Q2704-Voltage on all pins(located near SIO)?? Most probably its bad. Its a P channel mosfet.

but this transistor is empty sir, does it matter?

[Yosua]

Re: dell inspiron N5050 3v,5v alw no present

Q2704-Voltage on all pins(located near SIO)?? Most probably its bad. Its a P channel mosfet.

this is the measurement result of pin q2704
g : 3v
s : 0.04v
d : 0

[mcplslg123]

Re: dell inspiron N5050 3v,5v alw no present

Q2705 is there on mb?? If yes, voltage on all pins.

[Yosua]

Re: dell inspiron N5050 3v,5v alw no present

Q2705 is there on mb?? If yes, voltage on all pins.

I'm sorry if it took me so long to reply to this message, because now we are celebrating the big day here, this is the measurement of pin q2705

s = 0
g=3v
d=0.34v

I think this is normal?

[mcplslg123]

Re: dell inspiron N5050 3v,5v alw no present

Sorry, i asked to measure at wrong place. Measure voltage on Q2703/Q2706

[Yosua]

Re: dell inspiron N5050 3v,5v alw no present

Sorry, i asked to measure at wrong place. Measure voltage on Q2703/Q2706

this is for measurement
q2703
s = 3.26v
d = 3.27v
g = 0v

q2706
d = 0.96
s = gnd
g = 0v

[Yosua]

Re: dell inspiron N5050 3v,5v alw no present

any one can help me,?

iam so confuse with rhis trouble on this mobo

[mcplslg123]

Re: dell inspiron N5050 3v,5v alw no present

Q2706 Drain voltage is wrong at 0.96V. It should be 3.3V. Its pulled up from 3D3V_AUX_KBC and that voltage is present going by your measurement on Q2703. Check voltage on R2714-both sides. Voltage on pin14 of SIO??

[Yosua]

Re: dell inspiron N5050 3v,5v alw no present

Q2706 Drain voltage is wrong at 0.96V. It should be 3.3V. Its pulled up from 3D3V_AUX_KBC and that voltage is present going by your measurement on Q2703. Check voltage on R2714-both sides. Voltage on pin14 of SIO??

for measurement on pin 14 kbc is 0.72v - 1.21v unstable sir, and sorry I didn't find a resistor with code r2714 on the mobo, I think I need boardview