Samsung Monitor S19F350 19

[bennn]

Samsung Monitor S19F350 19" Main Board LS19F350 SF350 (P/N: 2017219005D121)
Hi! The backlight doesn't work, but the board itself works. I checked every diode on it and they all light up. Shim is definitely working as I changed it for a new one.

I found the datasheet for a similar chip OB3351.

VCC (1 leg)

14v comes

VDD (leg 14)

It has 3.5v.

Smd capacitance checked C913 it has a thousand nanofarads.

vLos-1.2% looks like it is working.

[CapLeaker]

How much voltage are you getting on the LED string? LED connected nd disconnected.

[lotas]

What is the voltage on the control pin (enable)?

[bennn]

What is the voltage on the control pin (enable)?

Hello! 3.5V.
I also want to add that I put a new ice driver from China as I know that they often fail.
That is, the OB3351cp is new and definitely working.
By the way, I found before that the 2nd leg was planted on the ground and it was the r919.
I took it off and a short passed and the chip started up.
I also want to add that before that I checked the led bar
by applying voltage to each LED and all of them are definitely working.

[bennn]

How much voltage are you getting on the LED string? LED connected nd disconnected.

I'm sorry, English is not my first language. Can you paraphrase?

[CapLeaker]

Measure the backlight voltage on the LED string connector twice, Once with the connector plugged in and one unplugged.
I wanna see what it does when you turn the TV on.

[lotas]

If pin 2 is grounded, then the mosfet is most likely broken, have you checked it?

[bennn]

Measure the backlight voltage on the LED string connector twice, Once with the connector plugged in and one unplugged.
I wanna see what it does when you turn the TV on.

Thank you very much for your help.

1.There is no difference if the voltage is static.

[bennn]

If pin 2 is grounded, then the mosfet is most likely broken, have you checked it?

Thank you very much for your help.
1.If I understand correctly, it is him.
I checked it with a tester, and I can say for sure that it's out of order.
2.Both of its contacts are connected to the ground, which is definitely not the case.

Plus, the low resistance from 2 contacts has not gone away.

[CapLeaker]

a mosfet has 3 contacts. The tab on the rear is connected to the middle pin and then there are the two outer pins. Gate, drain and source. So your second pic above is wrong, because the middle pin and the tab aren't in the calculation there.

[bennn]

a mosfet has 3 contacts. The tab on the rear is connected to the middle pin and then there are the two outer pins. Gate, drain and source. So your second pic above is wrong, because the middle pin and the tab aren't in the calculation there.

Okay, but in the 3rd picture it is pressed with all the contacts and also shows incorrectly.

[CapLeaker]

I don’t really trust these cheap little component testers and just test MOSFETs with my DMM, as I want to see that mosfet turn on and off again. What part number is written on the mosfet?

[bennn]

I don’t really trust these cheap little component testers and just test MOSFETs with my DMM, as I want to see that mosfet turn on and off again. What part number is written on the mosfet?

pb210bd

[lotas]

What resistance does the multimeter show between the three pins on this mosfet?

[CapLeaker]

Funny, it did see the body diode in the mosfet, but not the gate. Solder a little leg to the middle pin and use the socket again on the component tester… just curious…
but to really check that mosfet, test it with your DMM.

[bennn]

What resistance does the multimeter show between the three pins on this mosfet?

Gate–Source: >0.L
Gate–Drain: >0.L
Drain–Source: 1.44 kΩ

[bennn]

Funny, it did see the body diode in the mosfet, but not the gate. Solder a little leg to the middle pin and use the socket again on the component tester… just curious…
but to really check that mosfet, test it with your DMM.

I thought it was interesting too, so I soldered the leg on. That apparently the problem is not in him for sure. Something is putting the other leg on the ground.

[lotas]

Gate–Source: >0.L
Gate–Drain: >0.L
Drain–Source: 1.44 kΩ

It's broken, burned out, throw it in the trash, put in a new one.


P.S. Drain–Source: 1.44 kΩ, short-circuit all three pins together (when measuring with a multimeter, there may be a charge remaining, between Drain–Source it should show as a diode if you swap the probes between each other.

[bennn]

It's broken, burned out, throw it in the trash, put in a new one.


P.S. Drain–Source: 1.44 kΩ, short-circuit all three pins together (when measuring with a multimeter, there may be a charge remaining, between Drain–Source it should show as a diode if you swap the probes between each other.

Hello everyone!\
I changed the mosfet transistor
But it didn't help.
But then I noticed this resistor.I soldered it and the backlight came on!!!

[CapLeaker]

Which resistor?