TV tuner with an LVDS interface, or bringing an old monitor back to life.

I wanted to add a TV to the bedroom. In this situation, an ordinary person goes to the store and buys a new TV. But that didn’t interest me, and it seemed too easy, so I decided to make a TV myself—or almost make one :)
If you’re interested, come on in. I hope I won’t disappoint.

As it happened, I found an old Samsung monitor at home. But since monitors usually can’t receive TV channels on their own, I decided to order a small board to turn it into a TV.
Another reason for this decision was that the monitor had a minor “ailment”: vertical lines that would appear sometimes and disappear at other times. I suspected the VGA-LVDS board, so I decided to replace it, but I wanted to get more out of it than just a working VGA input.

Anyway, the board was ordered and delivered, and the mailing envelope was opened. Inside, in an antistatic bag, was the star of this review.


The board is made quite neatly; I didn’t find any damage. One capacitor was sitting slightly above the board (or rather, it wasn’t soldered flush against it), but that’s just nitpicking.
There are a few unpopulated component locations, but they don’t affect the device’s operation at all.


The board has two layers and single-sided component mounting; there are no components on the back. Almost all the connectors are labeled, but I’ll write more about them later.
The flux has been cleaned off; everything is neat.


The package also included a remote. Nothing unusual: just a regular remote, neat and lightweight.
The Chinese labels might put you off, but they’re not really a problem. Most of the buttons are intuitive, and I don’t need the others in everyday use.
The remote comes in a clear plastic bag.


The bag with the remote also contained an IR receiver. The thing is, if you buy a keyboard and IR receiver board for this kit, the receiver won’t be soldered onto it. The idea is that you can use the IR receiver without the board, and if you buy the extra board, the receiver is already included.


The remote uses the standard power source: two AAA batteries (some remotes use one battery or AA batteries).
Batteries aren’t included, so I bought the cheapest ones separately.



Let's take a look at the board.
First, here's what it can do.
Frequency range — 48.25MHz -863.25MHz
Color systems — PAL/SECAM/NTSC
Sound systems — B/G, D/K, l, M/N, NICAM/A2,BTSC
Number of channels — 200
Teletext — 10 pages (chip 39 — 10 pages, chip 59 — 1000 pages), though I doubt anyone needs it these days.
Video input formats (VGA, HDMI) — up to 1920 ×1080@60Hz
Supported video resolutions — 480i,480p,576i,576p,720p,1080i,1080p
Audio amplifier output power — 2x2.3 W(40) 1HD+N<10%@1KHz
Supply voltage — 12V (5 V is also an option; more on that later)
Panel supply voltage — 3.3V,5V, 12V

Connector functions, as shown in the photo.
Input connectors:
12 V power input
VGA input
HDMI input
Composite video and stereo audio input.
Audio input when using the TV as a computer monitor
Headphone output
USB input. (On this tuner, it's used only for firmware updates.)
Antenna or cable input.

The board also has these connectors:
6 pins — backlight inverter power, backlight on/off control, and brightness control.
14 pins — connection for the IR receiver, operating status LED, and keypad.
30 pins — LVDS signal output and panel power.
4 pins — speaker output.

There are also two jumpers on the board.
2 pins — switches the board's power supply to 5 V. Installing this jumper connects the 12 V input to the 5 V output. I'll explain why in the section on how I use it.
3 pins — selects the panel supply voltage: 5 or 3.3 V.
One clarification: only one jumper is installed. In my case, the panel happened to run on 5 V, and I was also supplying the board with 5 V.
If the panel needs 12 V, move the jumper to the two-pin section.
But panels like that are very rare.
If you plan to power the board itself with 5 V, it's easier to connect it to the power inductor lead closer to the corner of the board.


Board dimensions.


Here's the list of supported panel resolutions that firmware is available for (or at least claimed to be). Most are standard resolutions, but some are ones I've never seen before.
There is also firmware for 5- and 7-button keypads, as well as for different panel models and operating voltages (though as far as I can tell, the voltage is selected with a jumper).

As you can imagine, it's very difficult to test the board on its own, and almost impossible at home.
So let's move on to why I needed all this and what I planned to do with it.

For the connections, I bought a couple of connectors: a 2×15 for connecting to the panel and a 1×40 for all the other connections. The pin pitch is 2 mm.


I soldered the signal wires. I recommend insulating at least one row with heat-shrink tubing; the connector pins are quite soft, and if you pull on the cable, they can short together.
It probably won't burn anything out, but it could cause problems.


Next, I moved on to installing the electronics in the case.
First, I removed the standoff that was in the way. It used to hold the VGA-LVDS board.


After that, I moved on to modifying the power supply and inverter board. The board also happened to have a spot for an amplifier. I didn't know these monitors came with speakers.
I desoldered the input inductor, bridge rectifier, and capacitor.


Then I grabbed a pair of big, heavy-duty scissors and cut off a section of the board. Naturally, I first checked that I wouldn't cut off anything I needed.
I cut a small board from the piece I removed, where the desoldered components had been, and soldered them back in.


Next, I marked out where to drill holes in the rear (bottom) panel for the new board. I drilled some with a step drill and others with a regular drill, then finished them with a needle file.
Probably the hardest and most tedious part of the whole modification.


I bought 20 mm mounting standoffs with M3 threads at the market to install the board.
I also bought a pair of 1 W, 8 Ω speakers and a power switch.
In the end, I never used the power switch because there was nowhere to put it safely, so I decided to leave it out.


First test fit. Now you can see why I cut off that section of the board :)
I was going to explain it first, but then realized it would be easier to show.


I ran into problems with the rear panel, though. After cutting almost all the holes, I realized that once the board was installed, the plastic part of the case would block access to the connectors.
I had to move all the holes up (or lower the board, depending on how you look at it) by 7 mm. There was nowhere else to move it—the RF module was up against the case. I could have shifted the board a little and gained another 2–3 mm; I could even have installed it at a slight angle to make the connectors easier to reach.
In any case, the higher the board sits (relative to the photo), the better.
The holes for the mounting standoffs need to be countersunk, and you should use countersunk screws.


And here’s a brief note about powering the board.
The board was originally designed to be powered through the 5.5/2.1 power jack, with power then passed on to the inverter board.
In my setup, the monitor’s inverter board powered it.
But power supplies usually provide two voltages, 5 and 12 (13–15) V, and the original board is powered from 5 V.
I could have powered the board from 12 V, but that might unbalance the power supply, which is undesirable. Also, the original connector carries 5 V, so I’d have to add a jumper, cut traces, and so on.
There’s a jumper on the TV tuner board (for some reason, it isn’t mentioned in the manual) that connects the 12 V input to the 5 V output when installed.
In other words, the board becomes entirely 5 V.
This solution worked perfectly for me, except that the original power connector would then carry 5 V. To avoid damaging the original power supply (or the board if 12 V were applied to the original connector), I slipped a piece of heat-shrink tubing over the connector’s center pin, since I wasn’t planning to use that connector anymore.

Update/correction — Only one jumper is installed. In my case, the panel happened to run on 5 V, and I was supplying 5 V to the board.
If the panel needs 12 V, move the jumper to the two-pin section.
But panels like that are very rare.
If you plan to supply 5 V to the board itself, it’s easier to connect it to the power inductor lead closest to the corner of the board.


I then cut the 1×40 connector into smaller connectors with the required number of pins. I could have bought connectors with the right number of pins, but they cost a little more, and suitable ones aren’t always in stock.


A kit is available for this board, consisting of an IR receiver board and a keypad board.
But to preserve the monitor’s original design, I decided to use the old keypad. The IR receiver board wouldn’t have fit anyway. If you don’t want to solder, though, you can buy the kit.


The original instructions show how to connect seven buttons (so use firmware for 7 buttons). Each button is connected by a separate wire.


That wiring arrangement didn’t work for me at all, since it required a lot of wires and modifying the original board.
But the TV tuner board can also be controlled over a single wire by changing the resistance in the button circuit. In this case, all controls use the K0 contact.
k0 0 on/off
k1 680 V+
k2 1.5k V-
k3 2.7k source
k4 4.7k menu
k5 8.2k ch+
k6 15k ch-
k7 38k reserved

The monitor’s original board used roughly the same principle, but the buttons were divided into three groups.
The original circuit is at the top, and the modified version is below; no traces need to be cut.
Unfortunately, I couldn’t preserve the original button layout, because the monitor’s Menu button is the first one, and moving it there would have required extensive modifications.
I ended up with: channel down, channel up, menu, volume down, volume up, power.
Only three wires go to the keypad board: ground, buttons, and LED.


And this is what it all looks like on the monitor's original board.
Only three resistors are added: 680 Ω, 8.2 kΩ, and 1.5 kΩ. I added more because I lost the original 3.3 kΩ resistor I had desoldered. Two of these resistors are removed, and if you connect them in series, you get 6.6 kΩ, which is close to the required 6.8 kΩ. Since I lost one resistor, I had to improvise with others.
I used the original LED and soldered it so that it lights up in standby mode and turns off when the monitor is on. I figured that would be convenient. There's no point in having it lit when the screen is on—you can already see that the TV is working.


I connected the IR receiver directly, without any extra boards, since I was trying to keep the number of things I had to buy to a minimum. To connect the IR receiver, you need a couple of 2.2–10 µF ceramic capacitors and a diode. Usually a resistor is used, but for some reason the manufacturer recommends a diode here. Well, if that's what they recommend, that's what I used—and it works great.
By the way, the IR receiver is powered from the 5 V pin on the connector for the keyboard and so on. I don't recommend powering anything else from there: although this pin is marked 5 V, it's actually connected through a current-limiting resistor.
You can see above the size of the resistor I had to desolder from the original keyboard board: about 1 × 2 mm. So I don't recommend drinking before soldering :)))


Well, the monitor is starting to take shape.
When installing the mounting standoffs, put washers about 1–1.5 mm thick, with a hole diameter of 4–4.5 mm, between the standoffs and the monitor chassis.
The screws have countersunk heads, and the chassis metal is very thin. Without a washer, you can keep tightening until the screw twists off, but it still won't hold—the screw will bottom out against the standoff before it clamps anything.
I also mounted the power filter board, bridge rectifier, and capacitor on standoffs.
I desoldered the speaker connector slightly and repositioned it at 90 degrees to the board; otherwise, the speaker plug wouldn't fit.


Next, I tried to start the monitor, but hit a major snag: the inverter wouldn't start. I would have suspected it was faulty, but I tested it before the modification and it was definitely working. When I powered it on, the screen flashed once briefly, and after that I could only see the image with a flashlight.
After a lot of experimenting, I connected the old board, and everything worked.
I switched the power-control connection over to the new board, and it worked.
I found that there was no voltage on the brightness-control pin, even though it should be in the 0–3.3 V range.
I added a pull-up from this board output to 3.3 V (available on the TV tuner board), and everything worked perfectly. I suspect the board designers expected this pull-up to be on the monitor board.


The first successful power-up. Actually, this was the second one; the first was before I had the backlight working, when I was checking that the board worked and the LVDS interface was connected correctly.
You can see that the image size doesn't match the panel. Since the firmware can be updated without taking the monitor apart, I decided to do those experiments after the final assembly.
Don't judge the image quality—the antenna is just a piece of wire.


You could say the internal work is almost done. I won't claim it turned out beautifully—it could have been done better, but this works for me.
The IR receiver isn't secured in any way (you can see the hole in the center of the plastic frame), since the panel presses it firmly against the frame.
It's held very securely.


After that, I set the panel with its electronics aside and turned to the back cover.
I bought speakers 50 mm in diameter and about 7 mm thick (if I remember correctly).
To make neat holes, I printed drilling templates. They helped a lot.
First I drilled with a 1.5 mm bit, then enlarged the holes to 4.5 mm.


I glued the speakers in place with hot glue.
The speakers are rated at 1 W and have an impedance of 8 Ω. When I bought them, I was worried the sound would be quiet since the amplifier is powered by just 5 V. I was wrong—the sound is pretty loud.


Additional costs for the conversion.
Speakers, 2 pcs — 1.1
Standoffs = screws, 6 pcs — 0.37
Connectors, 2 pcs — 0.3
Components (4 resistors, 2 capacitors and a diode) — 0.15
7 m of MGTF wire — I don't know the price, let's say about 0.5

Total — 2.42 dollars.


First power-up after assembly and reflashing.
The instructions recommend holding down the Menu button while powering on to reflash the firmware. In fact, you can hold down any button—or not hold anything at all. Just insert the USB flash drive with the firmware and turn on the power. Reflashing takes about 30 seconds.
After flashing, the monitor's menu will be in Chinese, but switching it to Russian is no problem.
Press Menu, then press right twice (the gear menu), then down (the first line is highlighted). Use the left or right button to select the language you want.
The Russian translation is rather patchy: some of it is in Russian, some in English, but that's better than Chinese.
I won't go through the menu items; they're similar on all inexpensive TVs and usually don't raise any questions.


But I'll spend a little time on the engineering menu.
From the start, two things annoyed me: the TV turning on automatically when power was applied, and the volume changing too abruptly when adjusted.
I found instructions online for accessing the engineering menu.
While the TV is on, press Menu, then enter code 1147.
This is where you end up—


There's a lot more to explore here than in the main menu.
I found the auto power-on setting right away. I knew it had to be there and had looked for it in the main menu, but the programmers had put it in the engineering menu.
There are three options: on, last state, and off.
I chose the last-state mode.


I also found a menu where you can adjust the volume control curve.
I haven't experimented with it yet, but I don't think it'll be much of a problem.
You can set the volume level at different control positions: 0, 10, 20%, and so on.


That's it for the conversion. There's nothing to show on the front, since it looks unchanged; all the changes were made at the back :)


A closer look at the connector panel. You can see that the holes could be a bit neater, and a trim panel wouldn’t have hurt either, but I decided to leave it as it is.
In the center of the light-colored front bezel, you can see the hole for the IR receiver. That’s the only change to the front panel. Don’t worry that the receiver is facing down rather than forward—it works perfectly.



Summary.
Pros
The board arrived in good condition, with no damage or defects.
The device works perfectly.
It can be reflashed without any problems for panels with a different resolution.
The board really is universal.

Cons.
I couldn't find any.

My opinion: this is a perfectly good board for upgrading an old LCD monitor. This model can't play video files, but I don't need that anyway. What I would like is the ability to receive digital TV, but I haven't come across a version with that feature yet.
I like how well thought-out and simple the design is: nothing unnecessary, but it has everything you need to turn a monitor into a TV with relative ease.
The main thing is to have a panel and a case. You can use any 12 V power supply; the inverter is sold separately, and you can even replace the lamps with LEDs.

The TV tuner was provided for testing and review by the tmart store.

I hope this review is useful. I tried to bring all the information together and show that turning a monitor into a TV is pretty simple. Given the current situation, it's also a way to save money.