Dell Inspiron 3520 rsmrst missing Help

[admharsha7777]

I have this Problem with Dell Inspiron 3520 40_DV15 MLK MB 11280 mother board,
I couldn't found board view for this board I have similar schematic currently board not turning on.

+RTC_VCC is ok

RTC_RST# 2.5V on q2102 drain pin, in this mosfet gate RTCRST_ON_ showing 0V also kbc RTCRST_ON is 0V

SRTC_RST# also 2.5V

3D3V_AUX_S5 is precent
S5_ENABLE is ok
5V_S5 is ok
3D3V_S5 is ok
Ac in# is 0V
+5VA_PCH_VCC5REFSUS i don't know where to check

PM_RSMRST# No voltage
AC_PRESENT No voltage
KBC_PWRBTN# is 0.6V and when i press the switch it go to 0 and rice up.

I replaced bios bin form working same kind of board but no change. and no short anywhere in the board. also when i connected to power suply no change in amps 0.00amp showing in power supply. please anyone can help me to fix this board

thank you

[Techtiger]

Re: Dell Inspiron 3520 rsmrst missing Help

First, test the PSL_IN2 KBC pin 93, 73, and 74 supply
Then, test the BQ24707ARGRR pin 5 and 6 supply

[admharsha7777]

Re: Dell Inspiron 3520 rsmrst missing Help

First, test the PSL_IN2 KBC pin 93, 73, and 74 supply
Then, test the BQ24707ARGRR pin 5 and 6 supply

thank you so much for yor attention those pin voltages below. please help me.

PSL_IN2 KBC pin 93 - 0.6V present
KBC pin 73 PSL_IN1 - 0V (AC_IN# -0V)
KBC pin 74 PSL_OUT -0V
BQ24707ARGRR pin5, ACOK#- 0V
BQ24707ARGRR pin6, ACDET - 1.7V

[Sephir0th]

Re: Dell Inspiron 3520 rsmrst missing Help

I do not work on boards from this generation, but the missing voltage at PSL_IN1 might lead to a issue with either PQ4002 or PQ4006 (and perform a resistance to GND check.of PSL_IN1 ofc).

For PSL_IN2 I would not expect voltage there when we take into account where in the sequence the board is Stuck.

0V at ACOK# should be okay, since it is a logic low. 1.7V at ACDET sounds a bit low, but might be okay for this Controller.

I don't fully get how the PSL circuit works, but I strongly assume without bot PSL_IN present you cannot expect PSL_OUT.

Just a few hints.

Regards

[mcplslg123]

Re: Dell Inspiron 3520 rsmrst missing Help

Exact schematic for this board is perhaps not available.Q2703 is perhaps the PSL mosfet. Its a P channel mosfet,so gate voltage should be low for it to pass voltage from source(3D3V_AUX_S5) to Drain(3D3V_AUX_KBC). The part is DMP2130L. If its indeed Q2703 on your board, then try replacing it. If you dont have one in hand, then remove Q2703 and put a jumper between Source to Drain and see if mb works. You cant leave the board this way as battery will drain out fast-so ultimately part needs replacement.

[admharsha7777]

Re: Dell Inspiron 3520 rsmrst missing Help

Exact schematic for this board is perhaps not available.Q2703 is perhaps the PSL mosfet. Its a P channel mosfet,so gate voltage should be low for it to pass voltage from source(3D3V_AUX_S5) to Drain(3D3V_AUX_KBC). The part is DMP2130L. If its indeed Q2703 on your board, then try replacing it. If you dont have one in hand, then remove Q2703 and put a jumper between Source to Drain and see if mb works. You cant leave the board this way as battery will drain out fast-so ultimately part needs replacement.

3D3V_AUX_KBC generating properly 3.3V

[admharsha7777]

Re: Dell Inspiron 3520 rsmrst missing Help

I do not work on boards from this generation, but the missing voltage at PSL_IN1 might lead to a issue with either PQ4002 or PQ4006 (and perform a resistance to GND check.of PSL_IN1 ofc).

For PSL_IN2 I would not expect voltage there when we take into account where in the sequence the board is Stuck.

0V at ACOK# should be okay, since it is a logic low. 1.7V at ACDET sounds a bit low, but might be okay for this Controller.

I don't fully get how the PSL circuit works, but I strongly assume without bot PSL_IN present you cannot expect PSL_OUT.

Just a few hints.

Regards

PQ4002 not in this board ,
pq4006 Source pn is ground
D pin powe charger Ac ok present - 1.5V
gate pin AC_IN# is oV this gate directly connected to the KBC pin 73 (PSL_IN1)

this board is killing me

[Techtiger]

Re: Dell Inspiron 3520 rsmrst missing Help

PQ4006 open drain MOSFET: When the gate is at negative 0V, the drain will also be negative,PR4019 pin 2 It will be negative,AC OK present The voltage of 1.5V seems to be incorrect or PR4019 is not working properly, what voltage you get PU4002 Gate ?

[admharsha7777]

Re: Dell Inspiron 3520 rsmrst missing Help

PQ4006 open drain MOSFET: When the gate is at negative 0V, the drain will also be negative,PR4019 pin 2 It will be negative,AC OK present The voltage of 1.5V seems to be incorrect or PR4019 is not working properly, what voltage you get PU4002 Gate ?

PU4002 Gate valtage is - 1.4V
I chaneged PR4019 from same donor board
I also changed PQ4006
I reprograme bios again
also I changed q2703 and q2701 but the problem is same
also I grounded PR4019 pin 2 manually but nothing changed,
I don't think PQ4006 open drain MOSFET because I injected gate pin 3V then source pin become 0V but the problem still same,

I feel like probelm with q2102 as I mentioned before in this mosfet drain pin RTC_RST# is 2.5 V mosfet gate RTCRST_ON_ showing 0V also kbc RTCRST_ON is 0V, SRTC_RST# also 2.5V is this voltage normal??

I also attached schematic here

[Mod. Edit] Schematic -> https://www.badcaps.net/forum/showth...121#post992121

Reminder: rules and organization of this section
https://www.badcaps.net/forum/showthread.php?t=117483

[admharsha7777]

Re: Dell Inspiron 3520 rsmrst missing Help

when I grounded PR4019 pin 2 manually PU4002 Gate 1.4V valtage rise up to 9V, but in both cases 19V pass to the other side,

in the other hand RTCRST_ON not generating by kbc 120 pin, now I have no idea how to fix this one

[Techtiger]

Re: Dell Inspiron 3520 rsmrst missing Help

when I grounded PR4019 pin 2 manually PU4002 Gate 1.4V valtage rise up to 9V, but in both cases 19V pass to the other side,

in the other hand RTCRST_ON not generating by kbc 120 pin, now I have no idea how to fix this one

PU4002 is a P-channel Mosfet. The internal diode will conduct at +19V to switch on the +3/5V LDO, but this doesn't necessarily mean full switching
The BQ24707ARGRR internal logic includes a delay. I suggest you test the PU4002 and the Gate line. There should be 2 resistors. If the PU4002 is not in use, trace it back

[Techtiger]

Re: Dell Inspiron 3520 rsmrst missing Help

I don't think PQ4006 open drain MOSFET because I injected gate pin 3V then source pin become 0V but the problem still same,

The assumption was made based on the schematic I have in my hand. According to this schematic, the source is connected to GND. The schematic you uploaded illegible

[admharsha7777]

Re: Dell Inspiron 3520 rsmrst missing Help

the assumption was made based on the schematic i have in my hand. According to this schematic, the source is connected to gnd. The schematic you uploaded illegible

[admharsha7777]

Re: Dell Inspiron 3520 rsmrst missing Help

PU4002 is a P-channel Mosfet. The internal diode will conduct at +19V to switch on the +3/5V LDO, but this doesn't necessarily mean full switching
The BQ24707ARGRR internal logic includes a delay. I suggest you test the PU4002 and the Gate line. There should be 2 resistors. If the PU4002 is not in use, trace it back

please check the screenshot i marked voltages there

[admharsha7777]

Re: Dell Inspiron 3520 rsmrst missing Help

PU4002 is a P-channel Mosfet. The internal diode will conduct at +19V to switch on the +3/5V LDO, but this doesn't necessarily mean full switching
The BQ24707ARGRR internal logic includes a delay. I suggest you test the PU4002 and the Gate line. There should be 2 resistors. If the PU4002 is not in use, trace it back

here is power up sequence i marked voltages there. onlr rsmrst missing , I have no idea what to do

[mcplslg123]

Re: Dell Inspiron 3520 rsmrst missing Help

The diagram you're referring to is for 10316-1 with HM65 chipset whereas your mb is 11280-1 with HM76 chipset. A more appropriate diagram in this case is DELL INSPIRON 3420-11282-1. Its available in the forum.