Samsung np300e5a turn on but no image

[jp_jota]

Hello my friends, I need your help again. I am trying to repair a samsung np300e5a, which turns on but no picture appears and the fan runs at full speed, sometimes it turns on and everything is ok. in 10 times 1/2 works.
I just got a one schematic here in the forum and I'm not sure is correct for this model, and I do not have the boardview of this board, which makes it difficult to identify any component.

I notice also that the 1912a mosfet with 1.060v heats up a lot, And the coil next to it also heats, it replaces it with new and stays the same.

3.3v ok
5v ok
19v ok

MODEL: SCALA3-15 / PETRONAS-15 REV 1.5
BA92-09186A

thank you

[peste]

Re: Samsung np300e5a turn on but no image

clean ME region bios..

[jp_jota]

Re: Samsung np300e5a turn on but no image

clean ME region bios..

I never did and I do not know how to do it, I'll see how it's done and I'll try. thank you

[jp_jota]

Re: Samsung np300e5a turn on but no image

news: the mosfet 1912a not heat without cpu, and have the 1.050v and gpu not heat anything. the coil next to the gpu makes short with multimeter to the gnd and 0v. its normal?

[khaahk]

Re: Samsung np300e5a turn on but no image

Please define make short, in ohms.
1.05V is probably pch power supply line.
If machine boots then everything is fine, usb and so on?

[jp_jota]

Re: Samsung np300e5a turn on but no image

Please define make short, in ohms.
1.05V is probably pch power supply line.
If machine boots then everything is fine, usb and so on?

the pc does not boot, just turn on, sometimes it was all good, but the turn off did not start any more, I did a scheme with a photo to realize how it is. as I do not have the boardview of this board I can not identify the components. someone has?

[jp_jota]

Re: Samsung np300e5a turn on but no image

the pc does not boot, just turn on, sometimes it was all good, but the turn off did not start any more, I did a scheme with a photo to realize how it is. as I do not have the boardview of this board I can not identify the components. someone has?

edit. with back photo

[khaahk]

Re: Samsung np300e5a turn on but no image

4 ohm on video card and 13 ohms on cpu vcore are fine. The one that stands up is 0.64 ohms on PCH power line. Try to measure resistance without the coil to see on what side the low ohms reading is.

[jp_jota]

Re: Samsung np300e5a turn on but no image

in the position as it is in the picture taken. the left side that goes to the condensor has 00.68 ohms and the right side that comes from the mosfet has 5.760mohms but the value is always going down

[Techtiger]

Re: Samsung np300e5a turn on but no image

On the Schematic page 47 you have the Switch power 3.3V 5.5V 1.5V test those Fets

[jp_jota]

Re: Samsung np300e5a turn on but no image

thanks for the help. but i think this schematic is not for this model, i only can find the 0803gmt and 6912a mosfets.

[Techtiger]

Re: Samsung np300e5a turn on but no image

Not those Fets try this one in Pic

[jp_jota]

Re: Samsung np300e5a turn on but no image

Not those Fets try this one in Pic

ok, i will test now. and i find the real model of this board. its a BA41-01839A

[jp_jota]

Re: Samsung np300e5a turn on but no image

Not those Fets try this one in Pic

i edit a photo with voltage

[Techtiger]

Re: Samsung np300e5a turn on but no image

That Voltage is correct ok now Check SIO U512 MEC pin 49 40 4 35 32 61 42 43 75 34 65 103 101 90 85

[jp_jota]

Re: Samsung np300e5a turn on but no image

The voltage is:
49 - 3.3v
40 - 3.3v
4 - 3.3v
35 - 0V after resistor its 5v
32 - 5v
61 - 0,970 oscillating
42 - 0v
43 - 0v
75 - 3.3v
34 -3.3v
65 - 3.5v
103 - 3.3v
101 - 3.3v
90 - 0v
85 - 0v
I used this boardview to get this results

[Techtiger]

Re: Samsung np300e5a turn on but no image

all input Voltages for SIO U19 are Good, SIO commination with BIOS OK up to RSMRST but the PCH is not responding for SIO wake up signal , check if your PCH getting worm ? check with the Boardview PCH getting P3.3V near the caps & resisters (boardview Nets type P3.3V / P1.05V you will find them all ) check R252 for 3.3V both sides? Check PRTC BAT for any short on bios Batt? Test R160 with the multimeter without power, test pin 90, 43, 42 of U19 as you press the power button for any voltage one by one (# = high low), try and heat up the PCH with the hot are gun, find out if the Mob getting P12.0V_ALW also

[jp_jota]

Re: Samsung np300e5a turn on but no image

ok, i will see and i post, but in the case of the 12v_ALW i only have 9V and i can not find were is the 12V_ALW is created.

[jp_jota]

Re: Samsung np300e5a turn on but no image

R252 have 3.3v and in side gnd 0V. all 3.3V for pch is ok. prtc_bat not have short and have 2.9V.
R160 have 5V and from side the U11 is 0V and with multimeter without power have 10Komhs
i will check pins now

[jp_jota]

Re: Samsung np300e5a turn on but no image

the pins 90, 43 and 42 its 0V and its make a impulse when i press the on/off but i can´t see how much voltage.