Dell e6440 no display and shut down

[usyusy]

Dell e6440 no display and after some time shut down

The duration when power on some measurements are as under: on adapter, battery removed
(however when it gets shutdown, voltage are available just 19v, 3/5v)

19v ok
Ldo ok
3v/5v ok
Ram 1.35v and 0.67 vtt OK and DRAMRST 3.3v ok
Ram pwrgd ok
Pltrst on pin 22 of WiFi jack 0, however on io 3.3v
Slp_s3 on io 3.3v ok
Slp_s4 on io 3.3v ok
IMVP_Pwrgd on io pin 3.3v ok

PL700 battery/charger coil 13.54v
PL701 coil 19.67v
PL600/PL601 (PWR_+GPU_CORE) 0. 86v

PL 502/503 (+VCC_CORE) 1.71v but feels to be hot

PL301 (PWR_+1.05V_MP) 1.07v
PL201 (+1.35V_MEN_P) 1. 37v
PU603 (+1.8V_RUNP) 1.82v
U52/U53 (Flash ROMs) pin 8, 3.3v

Any guidance please.
Schematic is attached

[mcplslg123]

Re: Dell e6440 no display and shut down

All the readings seems good.Are you sure DRAMRST# is 3.3V?? It should be 1.5V. Bios flashed from known sources?? Ram Stick swapped??

[usyusy]

Re: Dell e6440 no display and shut down

All the readings seems good.Are you sure DRAMRST# is 3.3V?? It should be 1.5V. Bios flashed from known sources?? Ram Stick swapped??

oh sorry boss, it was same as Ram voltage i.e 1.35v. Ram Stick was swapped. Bios was not flashed. which bios should i program? EC or Main Bios? also i have noted two bios U52/U53 (Flash ROMs 64Mb/32Mb on page 18 PCH section) which should i flash. i request in the bios section.

[mcplslg123]

Re: Dell e6440 no display and shut down

Both the chips should be flashed at one go else there may be version mismatch between the chips.

[usyusy]

Re: Dell e6440 no display and shut down

Both the chips should be flashed at one go else there may be version mismatch between the chips.

Sir, how both the chips can be flashed

[usyusy]

Re: Dell e6440 no display and shut down

Both the chips should be flashed at one go else there may be version mismatch between the chips.

sir 1 chip u53 (io chip) was flashed successfully, however u52 (bios chip) was giving error as not detected, does this chip seem to be faulty or should do the process after removing from board as i was using on board flashing with cable clip.

[mcplslg123]

Re: Dell e6440 no display and shut down

I prefer flashing bios chip removed from motherboard.

[usyusy]

Re: Dell e6440 no display and shut down

I prefer flashing bios chip removed from motherboard.

Sir sorry for late response,
Main bios was replaced with another one {cfeon q64 104hip} and flashed
Same result boss., any guidance

[mcplslg123]

Re: Dell e6440 no display and shut down

What is the part number of original bios chip?? Is the new chip listed in bios support??

[usyusy]

Re: Dell e6440 no display and shut down

What is the part number of original bios chip?? Is the new chip listed in bios support??

Sir it was w25q64fv and same was replaced again but issue same, I noticed that about 47 sec board remains on but then off

[mcplslg123]

Re: Dell e6440 no display and shut down

The measurements seems all good-so difficult to guess what's wrong. Check carefully for corrosion under microscope.

[usyusy]

Re: Dell e6440 no display and shut down

The measurements seems all good-so difficult to guess what's wrong. Check carefully for corrosion under microscope.

ok sir, thanks so,
meanwhile some queries confusing me, if you can please mentor me in this regard:

1. Point 1

If we remove main bios and powers on, is it dangerous.

1. Point 2

Both EC and Main Bios pin 8 should show 3.3 even before triggering.

1. Point 3

"new chip listed in bios support??" where we can check this.

1. Point 4

If the value of some resister varies from its schematic value, is it problematic (especially for thermal section), e.g Vcore_NTC resister (470K_0402_5%_TSM0B474J4702RE) shows only 240 K,
similarly 2nd one (100K_0402_5%) shows only 54.9K. (attached on PCH_DPWROK line).
3rd one (130_0402_1%) shows only 64 ohm. (attached on +VCCIO_OUT & VIDSOUT line).

1. Point 5

If the resistance to ground of some component (Resister especially) seems to be ok on its various pins but its own value,when checked, not matched with the schematic, is it ok or not.

1. Point 6

what is the ideal resistance to ground of some component cap or resister, e.g more than 200 ohm as a capacitor (0.01U_0402_50V7K) showing 0.099 ohm (2k setting), is it faulty or suspicious.

Thanking

[mcplslg123]

Re: Dell e6440 no display and shut down

01. Its not dangerouus to poweron without main bios. But what purpose it'll serve??
02.Bios pin8 voltage depend upon whether its 1.8/3.3V chip. It maybe present before trigger(older mobos) and may not be present before trigger on newer mb with Deep Sleep Well(DSW) Technologies.
03.Descriptor region of bios. You can use UEFI tool to look there. Somes codes will be listed and you have to google them to findout the actual chip part number.
04.Thermal section resistor-Do you mean thermistors?? When you remove a thermal resistors, you should wait for some time and then measure it for resistance as they change values with heat.
05.Resistance to GND and value of resistor are 2 different things. Both matters.
06.No definite answer for this point. Resistance to GND varies from rail to rail and even from one mb to another. What value of resistance is ok-perhaps no one can give exact measure/answer-It all depends on your experience to conclude whether its value is ok or not.

I hope i've clarified whatever i know.

[mon2]

Re: Dell e6440 no display and shut down

(470K_0402_5%_TSM0B474J4702RE) shows only 240 K,
..2nd one (100K_0402_5%) shows only 54.9K. (attached on PCH_DPWROK line).

The ratio is the same from the original schematic value to actual stuffed value.

That is,

50% of 470k = ~240k
50% of 100k = ~ 54.9k

so the result of this voltage divider will remain the same as intended. Likely the vendor ran out of the original component value so they shifted the values to suit during PCB assembly time.

[mcplslg123]

Re: Dell e6440 no display and shut down

The ratio is the same from the original schematic value to actual stuffed value.

That is,

50% of 470k = ~240k
50% of 100k = ~ 54.9k

so the result of this voltage divider will remain the same as intended. Likely the vendor ran out of the original component value so they shifted the values to suit during PCB assembly time.

Agree with @mon2. We all change resistor value(specially in AD_ID) to force the mb to work on many occasions. However, whenever, you change resistor value in a voltage divider, the value of R2 should be low ,else the circuit wont discharge completely after power off and you may see symptoms like charging light glowing even after removal of adapter etc.

[usyusy]

Re: Dell e6440 no display and shut down

Thank you sir mcplslg123 and mon2 for much valuable guidance and concept clearance.

[usyusy]

Re: Dell e6440 no display and shut down

sir when the pins of two chips of IO were fluxed and hot air was used a little bit, its got stably powered-on. it was taking 1.12A on dc power supply and the keyboard numlock light was working now.

But currently has no LVDS to check its display, and by VGA/HDMI cable display/picture was not apearing on the external lcd (just a light black blink on the screen showing that some signal is going to the lcd when i press FN+External Monitor selection )

is it ok or normal or we should also confirm further with the help of DSO or some other method.

on LVDS connector i measured the following values:

pin 1
5V ALW = 5v
pin 2
Batt white led = 2.02V
pin 3
Batt yellow led = 2.02V
pin 4
Breath white led = 0.12V
pin 5,6,7
+BL PWR SRC = 13.63V
pin 8
PANEL HDD LED = 2.93V
pin 9
DISP_ON = 0V
pin 10
BIA PWM LVDS = 0V
pin 15
CVT LVDS BCLK+ = 0V
pin 16
CVT LVDS BCLK- = 0V
pin 25
CVT LVDS ACLK+ = 0V
pin 26
CVT LVDS ACLK- = 0V
pin 34
LCD EDID DATA = 3.3V
pin 35
LCD EDID CLK = 3.3V
pin 36
LCD TST = 0V
pin 37
3.3V RUN = 3.3V
pin 38,39
+LCDVDD = OV
pin 40
LCD CBL DET# = 3.3V

[mcplslg123]

Re: Dell e6440 no display and shut down

LCDVDD is zero and thats wrong?? Are you getting a milky white display on internal screen??

[usyusy]

Re: Dell e6440 no display and shut down

LCDVDD is zero and thats wrong?? Are you getting a milky white display on internal screen??

Yes sir, lcdvdd seems to be zero, actually I have no lvds or internal screen, only board at hand
However tried to get display on external but only black

[mcplslg123]

Re: Dell e6440 no display and shut down

First find out why LCDVDD is zero.