DIY Samsung 920nw monitor repair

In detail: do-it-yourself repair of a Samsung 920nw monitor from a real master for the site my.housecope.com.

Good day!
Brought Samsung SyncMaster 920NW Model: 920NW Model Code: LS19HANKSM / EDC Type No: GH19WS Released: 01.2008
Problem: backlight goes out after 3 seconds
Actions:
- soldering the power supply board and inverter - did not help.
- replacement of litas in the primary and secondary housing - did not help.
- viewing the power supply board and inverter for microcracks - not identified.
- no lamps were thrown - no lamps.
As a result, by typing, it turned out with a tester, on the m-me of the OZ9938G inverter, Z leg (Timer signal) when the On / Off signal is turned on, the voltage rises to 2 V. and the lamps are on, as soon as you remove the tester probe, they go out after 3 seconds. From the monitor circuit, the output goes through a resistor (10k) and a conder (2.2 / 25) to minus. Replacing parts did not help. An increase in the rating of the conder affected the duration of the backlight (from 3 to 10 sec.) I applied a voltage (0.28 V) to this signal from the microcircuit power supply (5 V) through a divider (for 5 V - a 100k resistor, for a minus - 10k), gave an On / Off signal and it worked. From the datasheet on m-mu OZ9938G TIMER signal - decoding like this “Timing capacitor to set striking time and shutdown delay time”. A search on the forums speaks of the poor quality of the lamps themselves or "cold" contacts (I did not understand the matrix, there is no experience yet).
Purpose of creating a theme: prompt, it will work.

First you need to check at least the resistance of the secondary windings of the inverter transformers and compare with each other, but it is better to measure their inductance.
Look at the oscillator at the cold ends of the lamps and compare with each other. And the lamps can be thrown together with another matrix without disassembling.

Video (click to play).

KAIGOR I agree with you.
I am interested in what I have disabled protection or something else. The monitor has been working for two hours already, I noticed that the BRIGHTNESS is not regulated, everything else works.

Monitor Samsung SyncMaster 920NW.

Fault - when turned on cold, it works for about 40 seconds and turns off.
Each time the monitor is turned on, it shows an image for 3 seconds, then the screen turns off.

Please tell me what it can be - an inverter, power supply, etc.?
Where to dig first?

Monitor Samsung SyncMaster 920NW.

Fault - when turned on cold, it works for about 40 seconds and turns off.
Each time the monitor is turned on, it shows an image for 3 seconds, then the screen turns off.

Please tell me what it can be - an inverter, power supply, etc.?
Where to dig first?

A Samsung SyncMaster 920NW LCD monitor has been repaired with a declared malfunction - it does not turn on.

We try to turn it on - indeed, the LED is blue, but there is no image. Well, let's take it apart. The monitor came with the stand unscrewed, so a little less time will be spent on disassembly.

Gently snap off the back cover with a pick:

We remove the protective tin from the lamp connectors, disconnect the lamp connectors and disconnect the loop going to the matrix, it should look like this:

We remove the iron frame with the boards screwed to it. We carefully examine the board of the power supply-inverter from the side of the tracks:

No crime is visible. Well, let's unscrew four screws and look at the board from a different angle (from the other side):

We take out the board from the tin, after having disconnected the connector going to the scaler board:

Carefully examining it, we see two swollen capacitors C815 1000mFx25V and c818 1000mFx10V:

Putting it all in reverse order. We include:

Turned on. We connect the vga cable to the system unit:

Working. We put on a four-hour run. Everything is working. The whole monitor malfunction was in the c815 and c818 capacitors.

By the way, I am now concerned that the video content on youtube is gaining more views than the presentation of information on the topic of repair in text form.I think maybe it's worth moving on to the video? After all, all Internet experts unanimously claim that video is the future of the Internet industry. I think it might be worth buying SjCam cameras and filming your repairs? Although, on the other hand, there are already a whole bunch of such channels on youtube. And what do you think? Is video or text the future? Or maybe there is some third option?

All photos were taken with a Kodak EasyShare C1530 camera.

ESR meter - ali.pub/ho6yg
Capacitors 1000 uF 25V - ali.pub/u64ve
Capacitor set - ali.pub/9uhxm
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