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.
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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.
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I changed the same conduits, as well as the R803 resistor, which was burnt out. All the other resistors, conductors and diodes rang, like all the rules, but the fuse burned out, after replacing the fuse, new ones also burn. What could be the reason, what do you think?
Thanks to! We will look and understand)
Call Q804 and D802, most likely Q804 is broken once R803 was burnt out
Is the mains fuse on? Diode bridge, mosfet and shimka in the primary unit, look
please tell me the wiring gray black pink white This is how I understand the backlight them, no matter how to stick it in?
A healthy monitor will turn on and display the message “check signal cable", Which will change its position and randomly move around the screen.
In the event of a malfunction, the monitor may turn off spontaneously after being turned on or not turn on at all.
The main symptoms and malfunctions:
- White screen
- does not turn on
- spontaneously turns off
- message "non-optimal mode" when a PC is connected
- black bars on the screen (wide)
From the experience of repairs:
A 2006 Samsun 920n monitor arrived at the company's seowis center with customer complaints about its performance. When turned on, the monitor does not start up, and the power indicator and screen blink at irregular intervals.
As a result of diagnostics, it was established that the inverter power supply unit is out of order in the device.
Due to the sufficient reserve of brightness of the backlight lamps and the excellent condition in general, the monitor was repaired in 20 minutes in the presence of the client.
The warranty for the work performed was 90 calendar days.
The symptoms of malfunction are described in the video below:
The monitor has a plastic cropper that can be easily disassembled
The tilt-adjustable stand is secured with four screws and removed for repairs:
The label on the back of the monitor provides information on the production date (2006):
The electronics of the monitor are covered with a solid metal case that serves as a screen and an internal chassis:
Inside the monitor there are 2 boards: an inverter power supply and a main board:
On Chassis: Power Supply Inverter Board
Internal defective and new inverter power supply:
Replacement health testing:
Checking the assembled monitor:
In the warehouse of the service center, power supplies and an inverter for Sasung monitors 17-19 inches are always available.
Samsung 920 monitor broken? Bring it in today and we will repair it in just 20 minutes!
The question about the samsung syncmaster 920nw LCD monitor is the following! When this monitor was turned on, it went out after 1-2 seconds, which was diagnosed as a dump of the cold ends of the upper backlight lamps (it was not possible to solder). There was a donor at hand, but only with lower lamps. I put the working lamps on top of the lcd matrix being repaired, and it’s working! But after turning on everything is ok, and then it happens as if the picture starts to brighten from above, somehow float and the colors slowly change. All this takes about 15-3 seconds. I turn it off. What is it also an inverter?
Maybe a dirty interface connector to the matrix?
The cat has 4 legs. Entry, exit, ground and food.
It looks like the matrix was hooked a bit - the train fell off from the glass or something else ..
Rom.by, what's in my name for you.
About a miracle. Everything worked! I pulled out and stuck the cable near the matrix, although there I did not touch the cable at all, apparently I slightly pulled it up when I stuck it in.Thank you guys so much.
A Samsung 920NW monitor has been repaired with a malfunction that does not turn on and the power button blinks. The monitor was in operation as a test monitor, it was used to check and configure computers. 920NW models have two main faults - inflated capacitors and backlights.
When the monitor was turned on, the LED on the button blinked at intervals of 2 seconds, this behavior is similar to dried capacitors.
It is necessary to disassemble the monitor by unscrewing the latches, I do this with a scalpel around the perimeter and remove the metal protection.
Next, carefully pull out the high-voltage wires so as not to break the latches.
Then we turn over the metal casing and unscrew the five screws to remove the board with the power supply and inverter.
After a visual inspection, a swollen capacitor of 1000 microfarads of 10 volts was found, this capacitor most likely stands in the power supply of five volts, it must be replaced.
I replaced the standard capacitor with 1000 microfarads of 25 volts, I always put capacitors with a voltage margin, they heat up less and work longer.
For prophylaxis, we check the rest of the capacitors with an esr meter; in our case, no more defective capacitors were found.
We assemble the monitor and install it on the technical run.
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Backlight Inverter Purchase Link - VGA Test Signal Generator - https://ali.pub/1jq01h.
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Hello everyone! This video is about Samsung SyncMaster 920NW monitor repair. It has a green tone, full screen.
ESR meter -
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Capacitor set -
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How to save money on Samsung 920nw monitor repair. Does not turn on. Such a breakdown is quite common. If you have similar symptoms, then without hesitation, disassemble and change the capacitors yourself. In our case, 10V 1000 ICF and 25V 1000 ICF. Of the tools you need only a soldering iron and a Phillips screwdriver.
Samsung 920NW monitor repair, goes out after 1-2 seconds after turning on. Join the VK group: There are more than 300 photo reports on laptop and monitor repair in the group.
monitor Samsung LS19MJAKSZ does not turn on, the button indicator blinks diagnostics of the monitor Samsung LS19MJAKSZ Yekaterinburg
Simple monitor repair samsung syncmaster 721n. Eliminates the problem of noise in the form of horizontal stripes.
It so happened that once the screen of the Samsung 740N monitor, which has faithfully served me for almost 11 years, suddenly went out almost immediately after turning it on. Other attempts to enable and disable were unsuccessful, because according to the signals from the sound card, the operating system was booted successfully, it became clear that the problem lies in the monitor. Of course, a radio amateur cannot so easily throw out an old electronic device without trying to fix it, well, or raskurochit broken device for parts, then how it goes.
A quick search [1-6] showed that the most common problem with this type of monitors is the failure of electrolytic capacitors in the power supply.In general, even the most novice radio amateur can do such repairs, so you can get by with the purchase of several radio components at the place of purchase of the monitor, which is a couple of orders of magnitude cheaper, the cost of your own time, of course, is not taken into account. But in order to repair something, you first need to get inside the monitor, do it carefully, without marks on the case, perhaps the most difficult part of the repair. First, you need to put the monitor face down, so that the surface of the screen would not be damaged, after that you should unscrew the screws holding the stand.
The back cover of the monitor is held by latches located around the perimeter of the monitor case. To open the latches, insert a strong thin object, such as an unnecessary plastic card or a metal ruler, into the gap between the screen frame and the back cover, and then sequentially and slowly unscrew all the latches holding the cover. Under the back cover, such a spectacle appears before us. In the next photo, the cover that covers the power connectors of the backlight lamps is also removed.
It should be noted that the metal casing visible in the photo above, to which most of the structural elements are attached, is fixed in the desired position with the help of the back cover and is not fixed to anything else. Before further disassembling the monitor, carefully document the wiring of all internal connectors. True, a real chance to confuse the connectors exists only for the power connectors for the backlight lamps.
Just in case, we fix the position of the remaining connectors.
Now, from the actual screen, you can remove the casing with the printed circuit boards fixed in it.
Then we remove the power supply board.
As expected, three failed electrolytic capacitors are visible on the board.
Finally, we disconnect the power supply board and remove the protective film that covers the board from the side of the printed conductors, this film is held on 3 plastic clips.
In addition to the obviously failed capacitors, a number of sources reviewed recommend replacing the capacitor C107 for preventive purposes.
This radio part has been replaced with a 47 μF x 250 V capacitor.
Just as the reviewed sources indicated, the fuse F301 breaks down along with the capacitors. In the photo, this is a green radio component, which is visible next to the swollen electrolytic capacitors.
We remove suspicious and clearly damaged radio components from the board. The main culprits are that the author of these lines was left without a computer on May 9, 2017.
In place of the failed radio components, we install similar capacitors. Instead of a 3 A fuse, a 3.15 A fuse with solder leads is installed.
After assembly, the monitor's performance was fully restored, after three weeks of intensive use, no deviations were noticed in the work. The author of the material is Denev.
Repairing the malfunction of the Samsung 920nw monitor, the image disappears after a few seconds, there is no backlight
This monitor was purchased defective for parts. There was no point in repairing the monitor to the client since the matrix was damaged.
Since the defect of the matrix was not a very large monitor, they decided to leave it for their service needs. We turn on the monitor and look at the declared malfunction "Samsung 920nw image disappears" - the monitor continued to work but the backlight disappeared.
Diagnostics showed that 1 backlight lamp is faulty in the monitor. Taking into account the fact that the repair did not need to be done efficiently, it was a decision to turn off the protection on the Samsung 920nw monitor.
To do this, on a capacitor which is connected through a resistor to pin 3 of the oz9938gn pwm, we solder a 500k resistor. After turning off the protection, the monitor turns on, the image does not disappear. For more even illumination, 2 llamas were left (one upper and one lower). The monitor works safely to this day.
Remember disabling protection is not good. If you need to repair it qualitatively, it is better to replace the defective lamp.
Samsung 920nw monitor repair picture disappears.
Today I will tell you how to repair an inverter with your own hands.
If your monitor has a defect that it turns off after two to three seconds after being turned on, and at the same time the image appears at the time of turning on.
A trance defect can be determined by a device for short-circuited loops, by resistance.
Usually one of the trances breaks. This is, in principle, a disease of monitors.
The simplest option, in the absence of a trance, is to install a new inverter, of which there are many on sale.
A detailed examination revealed a defect in one of the inverter trances. It is easy to check this: you need to try the working candle one by one, first at the exit of the first trance, then the second, and so on alternately. In a non-working trance, the candle will naturally not light up at the moment of switching on.
Without going into details, we solder the transformer of the TMS91429CT inverter so that the protection does not work.
After dismantling the trance, it will look like this:
Then we take a ready-made inverter, for the same number of candles (4 candles), which are freely sold on radio markets, radio stores, etc., such as: model SF - 04S402, dimensions: 135-45 mm. Or something similar, the main thing is to fit the inverter in size.
Next, we supply it with power and control, place it with Velcro in a convenient place. It may be necessary to increase the length of the wires from the lamps to the output of the inverter.
Here are some examples of inverter placement.
And here are examples of ready-made inverters.
It will not be difficult for a person to disassemble.
