DIY samsung 940n monitor repair

In detail: do-it-yourself repair of a samsung 940n monitor from a real wizard for the site my.housecope.com.

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.

I got the Samsung 940N monitor on the occasion. When turned on, an image appeared for a second, then the screen went out. During verification, a faulty backlight transformer was found (breakage of one secondary winding). There was no new transformer, and its replacement in workshops was slightly less than the cost of the monitor. It was decided to try to restore it at home.
The transformer was removed from the monitor board and inspected. Its design could not be disassembled. Since the converter for the backlight lamps was single-ended (there is most likely a gap in the core of the transformer), it was decided to carefully break it in order to try to restore it in the future (gaps during gluing should not greatly impair its operation).

Video (click to play).

With a screwdriver, its side jumpers were carefully broken off from the W-shaped core. Then, to free access to the winding, the plastic frame of the transformer.
The old winding was cut off and a new one was wound in its place, 8 sections of 80-100 turns in one section with a thin wire (it was 0.1), preferably even thinner is needed.

After winding the winding, the transformer core was glued with super glue. The photo shows the glued seam. The frame of the transformer was also glued together. It turned out without the upper protective part (the pieces were too small).

Below in the figure is a view of the transformer from the reverse side, the new winding is on the left side, the terminals are not yet soldered. After soldering the leads and dialing the transformer, the resistance of the new winding turned out to be much lower than the remaining one. Well, this is understandable, the new winding was wound with a wire thicker than the original one.

Next, the transformer was installed in the monitor power supply board (new winding on the underside of the board). The monitor was assembled and performance tested.
After turning on the monitor, all the backlight lamps lit up, the power supply did not go into protection. Test run of the monitor showed quite satisfactory operation of the repaired transformer.

It is also possible to restore the performance of the monitor without rewinding the transformer - by transferring the monitor to work only from 2 backlight lamps (one on top and one on the bottom), which can be powered from the remaining working secondary winding of the high-voltage transformer.To do this, it will be necessary to remove the SMD diode "CA2": D10 or D11 from the monitor's power supply board (depending on which transformer winding is faulty) and rearrange the backlight lamp connectors accordingly. The faulty winding will need to be mechanically, carefully removed (cut with a knife). After that, accordingly, the brightness of the monitor will decrease slightly, but the monitor will remain quite working.

They brought 2 samsung monitors for repair - 940n and 740n. Most often, these devices have problems with the power supply, but, interestingly, there are several modifications of these same units for the forties models. Our guys got one modification for both seventeen and nineteen inch models. Accordingly, we will describe the repair of this modification here.

The first thing to do is to look at the display from different angles (preferably with the D-SUB cable disconnected, which VGA goes to the video card). If it is noticeable that the inscription “cable not connected“Then this is our patient. The backlight does not work for the patient, and everything else is normal.

Of course, in order to fix this beast, it must be disassembled. This is done quite simply - we remove the leg and half the body. I half the body using this blue piece that looks like a pick (photo below). You can buy it in most radio markets and one such thing costs about 15 rubles. It is not suitable for any technique, but for both monics, one such was enough for me.

After all the latches are unhooked, put the monitor with the display down and remove the plastic cover. The next step is to remove the casing that protects the wires going to the backlight lamps and unhook the loop 2, circled in blue. The cover can also be removed easily with a small, thin, flat screwdriver. After removing the casing, we detach the wires supplying the backlight (pictured below).

The Samsung SyncMaster 940n monitor received for repair with a malfunction does not turn on, as the owner said that he served faithfully for 13 years, although the production date on the label is May 2007. The monitor itself is well preserved and this was its first renovation. How high quality monitors were made 10 years ago.

Well, I will not delay for a long time and start repairs, in fact, here he is our patient.

When plugged into an outlet, there was no image on the screen and the blue LED on the power button was constantly blinking, which can be assumed that the power supply is faulty. But let's not guess prematurely and from the beginning we will disassemble the monitor.

The monitor can be disassembled very easily, it is enough to unscrew three screws, remove the leg and click on the latch perimeter.

To separate the back cover from the muzzle, I use a medical scalpel, it is very convenient for them to do this. So that the scalpel did not press so hard on my hand, I put heat shrink on it.

We insert the scalpel into the gap between the back cover and the frame of the muzzle and unlatch the latches.

After removing the back cover, disconnect all wires and cables.

Then we remove the casing and turn it over. We unscrew the three screws and remove the insulator.

After removing the power supply board and the inverter, here they are combined, three pregnant capacitors were found about which there was a suspicion at the very beginning.

We solder the unusable capacitors.
For the sake of interest, we check them on ESR Micro. We see that the resistance is 0.63 ohms and the capacitance is 241 microfarads, which means that the capacitor has almost completely lost its capacity, which was originally 1000 microfarads.

We take out a new capacitor and also check it with a device.
Fine! The capacitance in the aisles of the norm is 980 microfarads and esr is 0 ohm, which means that the capacitor is good.

We seal the new capacitors into place.

Capacitors installed 2 pieces 1000 microfarads 25 volts and one 470 for 50 volts.
It remains to assemble the case and put the monitor on a technical run and then give it to the owner.

By the way, this monitor has a slightly defective matrix about which the client immediately warned me. So I won't buy a new monitor.

Thank you for your attention, good luck everyone!

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So, I decided to disassemble the monitor. It did not work right away, because how to understand how he understands is very difficult if you do not know the principle of disassembly. Okay, friends suggested. And I took it apart. How this is done is described here.

Having disassembled the monitor, I removed the built-in power supply board.
Here it is on the panel on which the monitor boards are attached (left board):

After I removed this board, I examined it closely. Almost immediately I noticed that one of the capacitors was slightly swollen:

It can be seen that from above, where there should be a flat round incised surface, it is slightly convex.

So, I evaporated this capacitor and replaced it with another one. Unfortunately, I didn’t have one with the same capacity (1000 uF), so I had to use it with a larger capacity (2000 uF). Here it is, already soldered to the board:

Next, I put the board in place, connected the previously disconnected wires to it, assembled the monitor and connected it to the computer. Included. It works!

So, thank God, the monitor is working! And 3 thousand rubles remained with me, and did not migrate into the pocket of someone else's uncle. God grant that it will continue to work properly. What I really hope for!

Repair of the SAMSUNG SyncMaster 940N monitor. No backlight.
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Video Repair of the SAMSUNG SyncMaster 940N monitor. No backlight. HamRadio Tag channel

A Samsung 940N LCD monitor has been repaired with a declared malfunction - the image disappears a couple of seconds after turning on.

We try to turn it on - indeed, after turning it on, the image appears for a few seconds, then the screen goes out, that is, there is no image backlight, the image itself is present. We will disassemble.

We snap off all the latches along the monitor body with a pick and remove the back cover. We inspect the inverter board for swollen capacitors - there are no swollen capacitors. We try to throw in external lamps (we change all four).

The lamps are on and not extinguished. Everything is clear - the matter is in the lamps (that the matter in the lamps was clear a little earlier, when red light prevailed in the image, which appeared for several seconds, since the lamps are used in two colors - blue and red, it was immediately clear that it was burning weakly (or not lit at all) blue lamp). We will change the lamps.

The matrix name of this monitor is HSD190ME13.

We remove the piece of iron with the power supply-inverter board and with the interface board - the scaler board.

We unscrew the 3 screws from the top and carefully bend the matrix board to the side. We snap off all the latches along the matrix body and take out the matrix itself from the iron frame.

Changing the lamp assemblies. The lamps in this monitor are installed CCFL 39cm * 9mm. Putting everything together in reverse order. We include.

We see a colorful splash screen with information that it is necessary to connect the signal cable to the computer. We connect - a beautiful image in which there is no longer a predominance of red. We put on a four-hour run with periodic off-on. Everything is working.

All photos are taken with Samsung GT-C3222 phone.

1 Precautionary measures

1-1-2 Maintaining the LCD Monitor

1-1-3 Fire and electric shock

1-1-4 Product Safety Instructions

1-2 Repairs - Precautions

1-2-1 General Service Precautions

1-3 ESD Protection

1-4 Precautions for Installation

2 Ttechnical specifications

2-2 Specifications for LS15HAA / LS15HAB

2-3 Specifications for LS17HAA / LS17HAB / LS17HAT

2-4 Specifications for LS19HAB / LS19HAT Models

3 Aligning and adjusting the image

3-1 Equipment Required

3-2 Automatic Color Adjustment

3-3 DDC EDID Standard Input Data

3-4 OSD Menu Adjustment When Replacing Panel

3-5 OSD Menu Adjustment When Replacing Backlight

3-6 Service Function Spec.

3-6-1 OSD service function display method

3-6-2; 3-6-3; 3-6-4; How to operate the OSD service function

4 Troubleshooting

4-1 No power (LS15HAA / LS15HAB)

4-2 No power r (LS17HAA / LS17HAB / LS17HAT / LS19HAA / LS19HAT)

4-3 No video signal (analog)

4-4 No video signal (digital)

5 Monitor Disassembly and Parts List

6 List of electronic components

7 Block Diagram

7-3; 7-4 Switching Power Supply (Inverter) Board

8 Wiring diagram

9 Schematic diagram

9-1 Circuit Diagram (15 '' Monitor)

9-2 Circuit diagram (17, 19 inches)

10 Installation and operating instructions

10-5 Attaching fasteners

11 Disassembly and assembly

12 Printed circuit board

13 Description of the circuit

13-1-3; 13-1-4 Inverter power circuit

13-1-5 Inverter protection circuit

13-3; 13-4 Inverter schematic diagram

14 Reference

14-3 Timing table

14-4 Preset Timing Modes

Samsung 940N was brought with a standard diagnosis - extinguished, dark screen... There are three inflated containers in the power supply 1000 microfarads x 25 volts - c301, c111, c112... After replacement, nothing changes.The inverter is assembled on a PWM controller BIT3195G and two assemblies of field-effect transistors.
We measure two AP4502 field assemblies on the back of the board. They are penetrated quite rarely, but it happens.
They represent an assembly of two opposite-sex field workers and are replaced by a more common assembly from the IRF series. I usually put IRF 7389 or IRF 7319... In this case, I blew my native 4502 from a similar monitor with a broken matrix. Image - DIY samsung 940n monitor repair

Sometimes it is limited to replacing the fuse in the inverter power circuit. In this case, it is F301.
It will not hurt to replace the capacitor in the primary circuit of the power supply unit 47 microfarads x 50 volts c107 and in the secondary circuit 10 microfarads x 50 volts C123. Also, just in case, I change 33 microfarads x 25 volts in the area of the c345 inverter.

It rarely happens that inverter transformers fail. In this case, they survived.

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.

Monitors Samsung SyncMaster 940N

A number of the most typical problems in the operation of monitors that sooner or later most computer users have to face are: no signal, problems with image transmission, its complete absence with a power indicator, image color distortion, backlight dimming after a couple of minutes of operation and the appearance this kind of lettering.

As a rule, problems with the monitor arise due to incorrect connection, incorrect settings or malfunctions of the video card. The Samsung SyncMaster 940N monitor, a fairly common model, will serve as an example for eliminating such a problem as the lack of a signal and the correct operation of the power indicator.

In general, this model is distinguished by ease of disassembly, as well as the free access of all the parts necessary for replacement, given that there is no external damage and only internal faults remain, so it is worth trying to carry out the repair yourself.

Before proceeding with the disassembly of the monitor, it is important that after disconnecting from the mains, some time has passed, preferably several hours, and in the meantime, prepare a Phillips screwdriver and prepare enough space for work, for example, a table and cover with a soft cloth.

For disassembly, the monitor is put down with the screen and, in turn, the fixing screws of the legs are unscrewed with a screwdriver, these are three pieces, and the cover is on four screws. There is no need to touch the rubber plugs.

Next, you need to be extremely careful to detach the back panel. Plastic is very fragile and can crack, so that this does not happen, it is worth using a thin and sharp object in the work. A scalpel is fine for this role. By disengaging each of the latches in turn, the lid will gradually open. It is important not to rush and work carefully so that you do not have to fix cracks.

After removing the cover, it is necessary to remove the second protective part of all internal electronics - the chrome plug. There is no particular difficulty here and it will be quite enough to slightly shift it to the side.

The next step is to disconnect all cables and a ribbon cable with side locks. These elements will only get in the way, and then the lid opens easily.

Now, in order to get to the monitor board, it remains to remove the plate and its three fastening bolts. Unscrew the bolts and remove the plate. All the electronic "stuffing" of the monitor is before your eyes and you can find the cause of the malfunction.

In this case, the cause of the breakdown of the Samsung SyncMaster 940N monitor was swollen capacitors, which can be seen with the naked eye, they need to be replaced, which can be ensured with soldering tools and proper skill, and the monitor will be ready for use, all that remains is to carefully assemble it without damaging the cable. If you are not sure of your abilities or it is not possible to perform a replacement, contact the repair specialists for help.

Samsung 940n monitor disassembly

Here is a step-by-step instruction on how to disassemble a samsung 940n monitor, a fairly popular model of LCD monitors, especially in the corporate segment. These monitors come to our service center with a "chronic" problem of this series - swollen capacitors (the power indicator blinks, but the signal is not displayed). Considering the ease of disassembly and the availability of the necessary spare parts, you can repair the Samsung 940n monitor without involving specialists from the service center. By the way, other monitors of this series (540n, 740n) are disassembled in the same way.

Attention. This instruction is not the ultimate truth. The author of the article does not bear absolutely any responsibility for the integrity of your technique. Start repairing only if you are confident in your abilities and have the appropriate education! And remember that you can always contact Triaservice specialists. We carry out high-quality repair of monitors samsung, lg, philips, asus, dell in Kharkov and the Kharkov region.

Samsung 940n monitor disassembly steps:

Unplug the monitor and place it face down.

Using a Phillips screwdriver, detach the leg, which is secured with three screws (you do not need to touch the rubber plugs). Attention.
It is necessary to detach the back panel very carefully, as the fasteners can crack (which, in principle, is not so scary). To open the 940n's lid, we need a scalpel or any other thin, sharp object.

Using a scalpel, we gradually open the lid, detaching the latches. Plastic may crack.

After removing the cover, go to the chrome plug. It is enough just to move it.

Then it is necessary to disconnect all interfering cables (including the cable, on the sides of which there are latches) 7. After that, the cover easily tilts

Access to the inverter board is blocked by a plate, which is fastened with three screws. We delete them.

We carefully inspect the capacitors for swelling. It is also worth checking the fuse.

Using soldering accessories, we replace them (2 * 1000mF 25V, 2 * 1000mF 16V, 1 * 470mF 25V, 1 * 47mF 50V).

We assemble the monitor in the reverse order, following this instruction. Pay particular attention to the train, as it can jam and interfere with closure.

We get a ready-to-use monitor.

If your samsung 940n does not work, it most likely needs to be sent to a service center or to the trash heap. Triaservice repairs lcd monitors samsung, lg, philips, asus and dell in Kharkov. We solve problems of any complexity, including replacing matrices. By contacting us you will save money, time and nerve cells. To contact the manager, go to the contacts section.

If you liked the article, please like it.

Greetings to all members of the forum! Actually, such a problem: a friend gave a Samsung 940N monitor about a month ago with a diagnosis “turns on and turns off after a second”, checked, really like this: turn on the power, an image appears and after a second goes out - the backlight goes out. I removed the power supply from it and put it apart disassembled. Today at work they brought exactly the same monitor with exactly the same problem, I think a typical glitch.
Honestly, I did not get my hands on the power supply from the first monitor, I checked only the diode assembly EN210A - alive, carefully examined - burners and swollen conduits (manufacturer of conductors SA..HA, the logo cannot be disassembled) I did not find, can anyone come across a similar , I think a typical glitch please tell me?
Thanks in advance!

from a type with such behavior - short-circuited turns in inverter transformers,
or a malfunction of the matrix itself, try to throw the loop on another, obviously working.

transformer see. In my area of вЂ ‹вЂ‹ it, a darkening on the board even formed. Poor fellow! Obviously overworked

Azzy rhombus <:>I'm not a magician yet - I'm just learning! 😛

Yeah .. you kinda. dying trance. or rather the secondary trance. To make sure, remove / unsolder the trance, and then measure the resistance of the secondary windings (there are two of them). Most often: that secondary housing, whose resistance is less, and died.

Well, run it on two lamps on one channel.

Rom.by, what's in my name for you.

Rom, and it's not easier to buy a trance for 2 lamps and plant, power it in parallel.

What do you mean - a transformer (the same as burned out) or an inverter assembly?

Rom.by, what's in my name for you.

It is difficult to find the same transformer for 4 lamps .. in any case, I did not succeed (it has one primary and two secondary). So usually only one secondary housing dies (two dead at once - did not come across). and so the rest, whole, you can use .. and in parallel use another trance for 2 lamps. but this is perverted! For it may take a long time to find the right one.

Shl. It's easier, of course, to buy an entire analogous inverter.
ZZY .. Options for solving the problem, IMHO, a bunch.

Transformers TMS91429CT have been supplied to Russia since September.
Ask in the nearest service may have already received, P / N BN81-04191A.

How to disassemble samsung 940n monitor

Monitor does not turn on
We disassemble:
We unscrew the screws on the back panel (in my case there were two of them). Removing the monitor stand.

We unscrew the housing latches with a thin spatula or screwdriver.

we open the case and immediately find a break in the wires going to the monitor control panel.

removing the back panel of the case, we take out the cable going to the monitor matrix and remove the galvanized protection on the left

under the galvanized protection, disconnect the power wires of the backlight lamps

remove the part with the boards from the matrix

Dry capacitors are found on the board. We change them. It was also later revealed that the fuse had blown. It is hidden under white insulation (in the picture, the location is marked with a green circle).
I use a tester to check the components

AliExpress.com Product - DIY kits Mega328 Transistor Tester Digital Combo Diode Triode capacitor + inductance + resistor + SCR LCR ESR Meter MOS / PNP / NPN Very cool, I recommend! Checks conductors, diodes, resistors, transistors and much more.

A burned-out transistor was found on the reverse side of the board. Because the transistors are connected, I decided to replace the second one immediately (I installed the IRF7389 transistors)

Putting it up in the reverse order.

If our instruction was useful to you, you can donate any amount for the development of the project.

Hello everyone. Today we will consider repairing the Samsung 940NW monitor, it does not turn on with a defect. When voltage was applied, the blue LED turned on, after which the monitor did not react to anything.

The owner insisted on a quick repair, so it was necessary to complete it within 1.5 hours.

To disassemble this monitor, you need to unscrew the three screws that hold the stand, after which you can start removing the frame.

Three screws that hold the monitor stand

To do this, it is necessary to drive the frame back a little from the inside, exactly until the first latch snaps off. Further, in the gap between the frame and the body, you can drive some kind of plastic spatula, and one by one unscrew the remaining latches.

Disassembling the monitor, removing the frame

Removing the bezel near the edge of the monitor

The edges of the monitor are particularly challenging, but with a little practice, everything is very easy.

You also need to be very careful with the wire that connects the control buttons to the main board, as it can be easily damaged.

The wire with which the control buttons are connected

After removing the frame and the plastic case, it is necessary to disconnect the connector to the backlight. They are located under a protective casing, which is fastened with latches.

Monitor after removing the case. On the left there is a plate that covers the backlight connector

Backlight connectors

The last to be disconnected is the connector to the matrix. To do this, you need to press on the 2 protrusions on the sides and pull it down.

Now the matrix can be put aside, and repair the boards themselves.

The matrix itself is backlit, after disconnecting the boards

By tradition, I started by checking the power supply. In the photo, this board is located on the right.

Monitor boards. Scaller on the left, power supply and inverter on the right

Unscrewing 4 screws and removing the board, I immediately came across two swollen capacitors.

Defective capacitors in the power supply

They were rated at 820 and 470 microfarads at 25 volts. For fun, I threw them on the ESR meter. As a result, one capacitor is not detected at all, the second is identified as a diode.

Test result of the first capacitor

Test result of the second capacitor

Having installed new capacitors, I decided to try if the monitor worked. I threw in the matrix cable and connected the backlight. The monitor began to respond to button presses, but there was no backlight. If you shine a flashlight, you can see the image on the monitor.

Image visible when illuminated by a flashlight

Next, I started looking for the backlight. Since the capacitors that were faulty were in the 16 volt supply circuit, I decided to check if this voltage reaches the inverter. As it turned out, there was no tension.

Measuring the voltage coming to the inverter. There is no voltage.

Voltage at the output of the power supply. +16.7 volts, but it never reaches the microcircuit itself

Looking at the path from the power supply to the inverter, I saw a soldered fuse. On the one hand, 16.7 volts came to it, on the other hand, there was no voltage.

Broken 2A fuse.

It became clear that the fuse had blown. In order to exclude a short circuit on the side of the inverter, I checked the absence of a short circuit with a diode continuity. The voltage drop was 339 mV, which is within the normal range, and there is no short circuit on the board.

Resistance on the +16 volt line from the side of the inverter. There is no short circuit.

The blown fuse was 2A, and having soldered a new one, I reassembled the monitor for testing. The monitor turned on. After checking the output voltages again, the monitor was assembled and given to the customer.

Model: LS16HAAKSB / EDS
Type: GH19LS

Good day.
They dragged this miracle in bulk.

Some pioneer tried to fix the roofing felts and break it. According to the owner, the problems with the monitor began with the illumination of the image and after a while the monitor stopped turning on.

In the power supply there were leaked condensers in the secondary and a dead fuse. After repairing the power supply, I tried to turn it on. Monitor turned on, backlight
worked, but the image turned out to be strange - for some reason it doubled horizontally. I have not yet encountered such a problem and I do not know what could be
bring her. Need help.

Filmed all the boards and the matrix for identification.

The firmware has flown, Write the model and model code correctly.

And the checksum from the sticker on the process.

there is no case at hand at the moment. I will write the model and model code only on Monday.

The monitor (LS19HALKSB / EDC / GH19LS) was repaired with the declared defect “the image disappears in 5 seconds after turning on”. The Suntronix BN44-000123E SIP-U5F (M) REV: MP1.0 Power Supply / Inverter board uses the infamous TMS91429CT high voltage transformer. During the check, a malfunction was revealed in one of the secondary windings of this transformer.Since it is not possible to purchase a new such transformer, it was decided to transfer the monitor to work from only two backlight lamps (one at the top and one at the bottom of the matrix), powered by a serviceable secondary winding of the high-voltage transformer.

To do this, you need to unsolder one of the D10 or D11 CA2 SMD diodes on the board (depending on which of the transformer windings is faulty) and switch the plug of one of the backlight lamps (the length of the wires allows you to do this). After that, the monitor's performance is restored, although the image brightness drops slightly, but it is quite acceptable for comfortable work (it is also recommended to play around with the settings in the monitor menu - brightness, contrast, color settings, etc.).

P.S. Other materials for the repair of monitors of this model can be found here: 1, 2, 3, 4, 5, 6, 7, 8, 9.

P.P.S. Another similar monitor came for repair, it had the same problem with a high-voltage transformer, I identified a faulty winding - the resistances of the windings were about 1.2k and 1.5k, respectively; the one with a resistance of 1.5k turned out to be faulty. Next, the diode D11 was removed, "corresponding" to this winding, the monitor was assembled and put for testing. During testing, after a while a characteristic “burnt” smell appeared, after disassembling the monitor and desoldering the transformer, visual damage (“burning out”) of one of the sections of the faulty winding was found.

Video (click to play).

Therefore, when eliminating such a malfunction at the monitor, the faulty winding still needs to be mechanically, carefully removed (“scraped out”), and not just turned off the protection by desoldering the diode. The main thing here is not to confuse, and not to remove the working winding, therefore, first we solder the diode, turn on the monitor, make sure that the monitor is working, and then remove the faulty winding “corresponding” to this diode.

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