Questions tagged [tv]

Use this tag for technical aspects of TV (video formats, for example). Shopping questions are off-topic and repair questions might be too localized.

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85 views

How to switch off the CATV signal on a splitter port

I'm trying to create some automation of switching off the CATV signal on a splitter port. Using a regular 5V Arduino relay module I've tried to interrupt the wire from the center of the coaxial cable ...
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1answer
58 views

Defective Transformer Replacement

I've been working on repairing a TV psu, and discovered that the transformer in it is faulty (reading O.L. on every combination of pins except for diagonal in ohms mode on the DMM) I've been looking ...
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2answers
87 views

Fixing composite video distortion caused by brightness changes

I'm modifying an old CRT to take NTSC composite input (it only accepts RF over coax.) I have got a good signal going in but it has this weird distortion going on. When the image is dark the pixels may ...
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79 views

How to convert composite AV signal or RGB to luma (grayscale)?

As the title says- how can you convert composite signal into luma?? As we all know, composite is just what it says, composite video with grayscale and color signal combined and luma is just grayscale. ...
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1answer
47 views

What is 'mis-registration' and 'mis-collimation' of television signals?

I was reading about early televisions and television cameras, and I came across these terms with no explanation.... They appear on Google on a few pages, but again I cannot find a definition....
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5answers
106 views

what do the colours of the wires on stereo speakers signify from old TVs and laptops? [closed]

I have a few laptop and a TV stereo speakers salvaged from old electronics in my possession and I have noticed a pattern that I cannot understand. Both the left and right of these speakers have two ...
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0answers
49 views

Why does changing CRT to HDTV lose antenna channels? [closed]

We have an internal antenna that is connected to a tiny CRT TV through a digital converter box. I recently replaced this CRT TV with an HDTV, and I removed the digital converter box since the HDTV ...
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0answers
76 views

Replacing a 6 V LED backlight with two 3 V LED backlights

I have a 65" TCL TV which have backlight problem and I have another 60" TCL TV with broken screen. Now when I opened both TV to swap with LED backlighting strips, and I and I noticed the 60&...
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1answer
85 views

Why my television provider doesn't measure the coaxial cable length?

I recently put cable TV in my room (we already had cable TV before, but not in my room). The technician from my TV provider, through a split, ran a coaxial cable up to the TV in my room. When he did ...
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38 views

Can you find informations about this IC? D61422F1

Could you find the information about this IC, like its datasheet or something. The IC name is D61422F1 17B and the next line is 1317EV007G Here is the image: I found this IC in a TV box, in this case ...
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1answer
60 views

Meaning of TV Backlight LED strip details

I am learning electronics and I just disassembled a broken TV with the purpose of reconverting it into a smart light lamp. The issue is that I don't understand the details of the backlight LED strips. ...
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2answers
70 views

troubles getting serial port tv to work

i recently posted a question, but didn't had an answer (my fault :) ). my question wasn't straight-forward and clear. so my final goal is to communicate between nodered (raspberry-pi) and my lg tv. I'...
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0answers
73 views

How to get static on CRT screen instead of black screen?

The TV in question is a Sony Trinitron KV-14M1D CRT. I know it sounds backwards but I need the screen to show white noise for a project (oscillograph); but there seems to be a static block that ...
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0answers
286 views

Why don't LG RS232 commands work when the TV is on (only responds when off)?

I'm writing a new question after stumbling across this question which appeared to have similar symptoms: LG RS232 Commands partially working. As the other question noted, the power on command ...
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3answers
117 views

Old tvs, how did storing settings work, and what changed in the tv when we tuned a channel?

I don't have an EE background, but I would like to understand some aspects of old TVs. When we tuned channel what exactly changed inside the tv. Was there a circuit card in the tv where something ...
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7answers
5k views

How did old television screens with a light grey phosphor create the darker contrast parts of the display?

Many old television screens have a very prominent "light grey" color to the glass, I'm guessing from the phosphor, create darker areas if the effect of electrons make the phosphor glow? Is ...
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0answers
77 views

How to test TV LED backlight failure [duplicate]

I recently picked up a Braum (Aldi) TV from the nature strip to play around with. The TV seems to work perfectly fine (Channels, DVD input, sound etc) except that there's no working backlight. I've ...
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2answers
1k views

"shark teeth"-like PCB feature in high voltage section of modern HDTV

I found this tooth-like non-masked, solder-covered trace pattern on modern single board HDTV. It's in the 120VAC "HOT" section of the switch-mode PS. Looks like some sort of spark gap or ...
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0answers
103 views

How to adjust picture geometry of a CRT TV?

I have a HD CRT TV (Silva Schneider 26 inch) which failed recently. So I took apart a working CRT TV (Philips L01-2E AA, 20 inch) and took its mainboard and connected it properly to the HD CRT tube. ...
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1answer
43 views

Which components should be checked on a faulty tv power supply? [closed]

So, I'm new to working with electronics and I didn't study electrical engineering or anything related. I've collected some dead tvs and monitors over time hoping that I'm gonna fix them. I managed to ...
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1answer
89 views

Very old dual coaxial TV outlet, how to fix it to connect to a modern TV? [closed]

i've recently moved into an older updated apartment building and want to connect to the TV outlet but have a connection that i've never seen before. Can someone point me in the right direction of how ...
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3answers
52 views

Light coming from the room influencing TV

Inside the TV Remote we have a LED of infrared light which sends commands to the TV. Isn't it influenced by the light of the room(if any?).I thought if an electron in the valence band absorbs a photon ...
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4answers
573 views

Why faulty, old CRT TV produce ozone

I have an old CRT TV which had to be switched ON for half an hour or so for the picture to stop being blurry and be 'viewable'. During this initial warm-up time there was a 'static' like noise coming ...
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2answers
162 views

LED indicators intensity standards

I am trying to find any resources on the LED parameters (i.e. preferred intensity and luminosity ranges) that are used as indicators in various home appliances, such as Networked devices (i.e. routers)...
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0answers
339 views

How to ground a flyback transformer?

I designed a 50,000 volt power supply, that I am having problems with on grounding the HV side of the output. The HV appears to be injecting HV into my logic sections through the ground, damaging the ...
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1answer
134 views

Ratio of colors to produce white in color television

If you consult pretty much any book on the theory of color television, it says that because the human eye is more sensitive to green than red or blue, the reference white for color television has been ...
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0answers
50 views

GSM vs TV broadcating

Is it true that GSM signal's field strength in the atmosphere is dependent on the current number of users whereas for TV and FM broadcating the field strength is usually constant, independent of the ...
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4answers
5k views

Why are color difference signals transmitted rather than R,G,B signals?

In color television systems back in the early days, people used to transmit color difference signals (Y-R) and (Y-B) along with Y, which is the luminance signal. My question is why are color ...
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0answers
45 views

How do I reinforce a cardboard antenna for outside use?

I bought Mohu Releaf cardboard antenna. It works much better outside than inside. Mohu explicitly advises against outdoor use of its indoor models, yet I wrapped it in a plastic bag and hung it out of ...
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3answers
202 views

Will an RF modulator provide NTSC System M spec video from a DVD player?

I've been attempting to recreate the effect of an old NTSC television broadcast lately with the use of DVDs. The DVD-Video spec allows for up to 720 x 480 pixels at a display rate of 29.97 frames per ...
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5answers
2k views

Could an analog TV signal be transmitted over broadcast RF from a composite cable somehow?

My understanding is that an analog video signal (PAL or NTSC) has a particular form/structure. That signal can be transmitted over the airwaves at a particular frequency, & multiple analog TV ...
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2answers
68 views

Is it possible to build a fake flash drive for the TV that is in reality a share drive?

Problem I hate having to copy what I want from my PC to a flash or external drive and then stick it in the smart TV (which already has the ability to browse files on a flash drive) every time. I want ...
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2answers
148 views

What is this component of a TV called? [closed]

I am getting a burning plastic smell from the behind vents where this component is located. What is this component? Better quality image here: https://prnt.sc/rarfs6 EDIT: The TV in the picture is ...
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3answers
110 views

Why is a horizontal rod a full wavelength oriented radially to a broadcast antenna not the best receiving antenna

I have always struggled to get a good physical understanding of Electromagnetic waves. I've done the whole Maxwell's equation approach, wrote boundary element solver tool but cannot rationalize that ...
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1answer
365 views

Making a Remote Control for My TV from Scratch

This might seem silly to many of you, but I lost my TV remote when I moved awhile back and instead of buying a universal remote for cheap, I want to make a remote for my TV from scratch myself. I'm ...
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1answer
105 views

What are these wiry protrusions on a TV antenna?

This photo shows part of a large antenna assembly which has a series of thin wire protrusions: (Source) This antenna is apparently used for TV transmission. What are those protrusions for? I'm ...
4
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1answer
287 views

How did the Telstar 525/405-line conversion system from 1962 work?

The Wikipedia article on the Telstar satellites from the early 1960s says that in order to facilitate transatlantic television signals (where the US had the 525-line (480 visible) NTSC system, and the ...
2
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1answer
232 views

How to avoid signal interference between 5 volt analog video signal and 415 volt servomotor and drivers, when working nearby

I am using a 5V borescope analog camera (Sony CCD, PAL/NTSC) for visualization purposes. This camera has a 20 meter 4 core wire, which transmits power and video signal to and from the camera. Along ...
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2answers
587 views

What makes "quality" analog AV cables better than cheap cables? [closed]

I want to upgrade my retro game setup from a mix of composite and RF to a mix of S-video and component, with some composite for the really old stuff that doesn't support S-video. How can I distinguish ...
3
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1answer
686 views

Identifying SMD component 22P W8

I've been trying to identify a component on a main board for a TV that I believe to be faulty. As I haven't been able to come up with anything that I feel confident about, I'm hoping to get some ...
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2answers
2k views

Circuitry of TV splitters

I'm trying to understand the circuitry of TV signal splitters and associated boosters/amplifiers, and I have two questions. My situation is as follows. I have a TV aerial (antenna) in my loft. It ...
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1answer
190 views

Where can I get a display screen with 30 Hz or less refresh rate? [closed]

I am experimenting with a camera recording a display screen. Based on what I have read - camera recording a screen will have flicker if the refresh rate and frame rates are not synced. My mobile ...
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2answers
170 views

Project - How to onstruct a circuit to introduce and control a 0-300ms delay in an RF feed from a Sky Box to multiple TV sets? [closed]

Just bought a new TV! It's "smart" but where my previous dumb TV didn't, my smart TV introduces a delay over HDMI from my Sky+HD box compared to the RF2 output which is wired via coax cable to the ...
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1answer
834 views

What does a TV receiver circuit look like? [closed]

I found a few circuits for TV transmitters, but no receivers. I've looked at other simpler RF transmitters and receiver, but it's not obvious to me how to reverse the circuit that I have. I want ...
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0answers
8k views

CRT TV NOT TURNING ON [closed]

I'm a beginner in electronics repairing and I need help troubleshooting a tv which doesn't turt on, neither the power LED lights up. The board is a cheap chinese (check the attached image). When I ...
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2answers
716 views

TV capacitor 54j 6kv swc [closed]

My television (the brand is Philips) died and I'm trying to save it, When I had open it I had see a dead capacitor (54j 6kv swc), the most similar I saw was on Ali express with (54j 6kv), I don't ...
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3answers
1k views

Two TVs use the same antenna, but one affects the other

I’m having a problem with my TVs. I will call them TV1 and TV2. TV1 is Asanzo brand, and TV2 is LG 4K, which is much more expensive. After replacing the antenna wall socket of TV2 (The TV is near to ...
2
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1answer
884 views

127v 60hz TV to 220v 50hz [closed]

Hi all I recently moved from Mexico to Portugal and brought some electronics I suspect they are multi voltage and multi frequency. But reading the label of a Sony TV I got into doubt if it is or not ...
4
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1answer
279 views

How do we know off-screen area in TV?

I'm trying to implement HDMI to FPGA and vice-versa. Currently I'm referring with https://www.fpga4fun.com/HDMI.html site. But I'm confused that "But video signals usually also have an "off-screen" ...
5
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1answer
3k views

How do LCD screens repair themselves?

Hey, electronics people: A few months ago, I cleaned a spot on an LCD flat screen. Whatever it was, it was stuck on there pretty good and I guess I pushed down on it too hard (actually wasn't hard at ...