Dell E6430S No screen help request

[angel35]

I receive an wrong Dell E6430S, Not start no have screen.
Spec:
S mean Slim, not normal "fat" E6430, CPU soldered BGA CPU: i5-3340M SR0XB
Motherboard: Compal LA-7741P QAL70 r1.0 A00


Symptom:
Not start no have screen, no have backlight (full black), but board is working, Status LEDs ok, CPU start to hot and Fan spin up. Northbrigs also hot.
Main Battery charging, and can run form battery (run means you can turn off, CPU is hot, fan works)

Looks like everthings ok, but not work

I changed Memory, plug out SSD,(SSD ok), Keyboard plug out ..same.
Cmos battery voltage 2.9V
Memory voltage ok,
External screen D-Sub VGA same, no have screen. (mini HDMI not checked, i no have adapter)
USB 5v ok
As I can measure has voltage CPU 1.0 ok 0.9V and etc...

but missing
+VCC_GFXCORE 0V
PQ24 and PQ21 fet High switching (power)
PQ25 and PQ26 fet Low switching (GND)
But basic Gate controlling also missing

+GFX_DHB and +GFX_DLB 0V
It is comes from PU9 MAX17511GTL+T_TQFN40
But this IC related for cpu core voltage too. And that is good...I don't know why not start


I have post card TL611 Pro (with mini pciexpress adapter)
Power plug in ->start immediatelly just power on led light. CPU heating -> Postcard start to drop numbers and characters...and finally stop at "98."
Power off with button -> Fan speed up and turn off.
Power On button-> looks like start, Post card start to drop numbers and characters...and finally stop at " d7"

If I wait CPU will be Hot and Fan start.....cold temp-> fan stop and again... So looks like GPU area not works.. or I don't know.
Based on internet search "d7" means:
“No console input device found ” . Please ensure you have a keyboard plugged in the system.
and
"98" means: just Input devices initialization

Keyboard Ps2 Fan etc U51
MEC5055-LZY_DQFN132

Have you got idea?
Please help a little bit.

Have you got idea?
Please help a little bit.
Thanks

[mcplslg123]

GFXCORE is quite irrevalent for diagnosing the problem as it will rise under load only and you simply cant measure it with multimeter. You need a scope to do that.
Is your mb posting? Connect a usb keybaord and check whether numlock key glows on toggle.
I beleive its not posting so will be futile to check gfxcore and display.

[angel35]

GFXCORE is quite irrevalent for diagnosing the problem as it will rise under load only and you simply cant measure it with multimeter. You need a scope to do that.
Is your mb posting? Connect a usb keybaord and check whether numlock key glows on toggle.
I beleive its not posting so will be futile to check gfxcore and display.

Yes it is not posting, just debug card show 98 or d7
I try the USB keyboard, nothing happen, not show numlock leds.., But USB 5V is ok. Mosuse light on normal USB port and Esata/ USB too.

I start to check voltage on keyboard conn, but looks like ok +3,3V or 5V

Dell laptops need every time the Keyboard?
I mean I not attach keyB+touch -> Fail I attach the keyboard+touch, ->Fail Becasue keyboard is maybe not good.
So should be start without keyboard?

Bios can be cause this problem?
I found 6430s file here.. but I'm afraid i create an new problem on board.

[mcplslg123]

If its not posting,your focus should be on diagnosing the mb and not keybaord.
Check whether DRAMRST# is present or not.

[angel35]

If its not posting,your focus should be on diagnosing the mb and not keybaord.
Check whether DRAMRST# is present or not.

Ok i will check

Additional information Pressing "D" button ->Screen tunr on and Red, blue Green White pattern change again and again . Test patterns.
So Looks like screen is ok. Maybe.
...and If i press D button, it means keyboard is good?
Memory voltage 1.5V present.
When I remove DDR3 memory, appear different error code and flashing the 3 leds (battery, HDD, wifi) on keyboard frame... And as i read it is an DELL error code.

Ok i will check DRAMRST#

[angel35]

Solved
Bios and EC reflash U52 and U53.https://www.badcaps.net/forum/troubl...41p-intel-bios
...and need reset the bios SAtA boot options etc.
But new symptom A12 bios not possilbe to upgrade Not work windows methode and freedos usb methode neither. And As i read internet reddit etc lot of same problem.
...and RTC coin battery really fast runs out, and can't start the board...Very strange After some try or without SSD Board again dead. but different than before CPU problem side leds flashing Post coide 32 -> CPU problem
Reflesh again the Bios and EC, but now the W25Q32 flash U53 ...hard to communicate...Not start the read or write.
Anyway board again live.