I often think back to TV sets of old. The joy of dismantling one!
The quality of the Turret Tuner!
The complexity of the dual standard chassis with long solenoid operated switches.
The hinge out Convergence Control Panels.
Later FST TVs - amazing tubes and scanning technology.
How the heck does a LCD TV work?
Start with a computer... Every problem can be fixed by throwing a computer at it now :)
I think back also. The Dual standard black and white tv with its bowden cable operated swtiches for IFand timebase and the of course the need to make eht transformers that did not grumble too much at the two different frequencies and chuck out too much eht so the picture shrank. AC coupled videos so no blacks etc.
Not sure about the quality. Most of the early crt colour sets really needed a live in engineer, hence the rental market. Things were always burning up or just dying and the power consumption on many was high.
I can recall with fondness working in a factory making these sets and marvelling at over and over again it was the women who could do the best and fastest job of purity and convergence on them.It was seemingly black magic of some sort, as many of us blokes never managed to get them as good. Those times are of course long gone now. You ask how do modern tvs work. Basically modern tvs are really just computers running software with integrated parts like software defined receivers decoding chips and software to configure it all. Indeed I believe a lot of tvs these days use a modified version of the Android phone operating system. One annoyance these days, particularly with older people is that they take a long time to get themselves up and running. We of course, used to good old valves marvelled at the early transistor tvs coming on almost instantly, but now they can take up to a minute, and people are impatient with them and screw things up by jabbing remot buttons inappropriately and the saying the tv does not work. Toshiba are a particular problem as they also use wireless tech for the remote so it works from the next room and people now have so many remotes for so many things they tend to use the wrong one and all sorts of things happen! LCD and other flat screens tend to be of several types The basic lcd screen is a multi layer lcd, that works a bit like a Polaroid filter so light cannot get through it if its polarisation is opposite to a fixed one. However you need several for the colours and of course some form of back light. There are lots of variations on this theme, and now of course they are starting to use leds themselves as pixels too, not just as backlights. Viewing angle can be an issue when you are dealing with polarised light of course, but the clever trouser types seem to be doing very well at mitigating this problem now. Most of the driving of such displays is done on a matrix of horizontal and vertical address lines but a chip handles all of this stuff for you and also the correction of the very non linear law of the display.
I could write an essay on all of this stuff and be accused of over simplifying, so if you really want to know there are lots of technical books around that will probably send you to the funny farm. good luck Oh and one tradition of tvs has not changed. They all still have crap sounds speakers in them.
Brian
And then if you are over a certain age you have to press the buttons really hard on the remote if you don't get the response you need.........
In message , Brian Gaff writes
Two traditions. Crap speakers and most of what they receive is utter crap.
Then later, the insides of the 70s TV used for this project.
Building a Fallout Style Computer - Retrofuturism!
Lots of mechanical engineering to hold that TV together with access and serviceability for base level components, leaving enough air space for ventilation. Still an admirable part count, that felt something had indeed been purchased when the readies were handed over.
Now it's the specific arrangement of electrons inside memory devices and things hidden as propriety secret in non-disclosure that extracts the dosh next to the colour of the case and, of course, the brand name. The outside arrangement of components and modules is lightweight and inexpensively boring, its the firmware that excites and gives it life.
Yup, it's a computer ...
Badly! Poor picture quality, totally crap sound, random switch off>
I thought it was all problems can be created with a computer.
getting electrocuted ?.
Rubbish. Much better picture quality, especially in HD, no pincushion or barrel distortion, no colour registration problems, no focus problems.
Indeed. And with enough spend on the LCD, great color and viewing angle. And often faster reponse to scene change.
To me, the sound of modern TV sets is vastly inferior to what the old ones had. We had a Pye, I believe, with a 6" loudspeaker, which weighed A LOT. I don't see that on modern skinny units.
But go back further to the 1950s and the sound was horrid. When I got my current 50s set I didn't expect middling sound, but it's worse than I thought it would be.
NT
When our 8 year old Samsung packed in I took it apart looking for the obvious. There was nothing obvious, I know nothing about tellys. I put it outside for the pikey scrap men, they did not pick it up. So, I smashed it up and put the bits in the wheelie bin. The speakers were like postage stamps. There were these thin tubes behind the screen, so I guess that one of them had failed. Thumping the screen made it work for a very short while. That lump of junk cost ?800.
405 line (VHF) sound was AM, so rather more difficult to design a decent receiver for. Lucky to get to even 10kHz. But that didn't stop the makers using the cheapest possible power amp and indifferent speakers too.
With modern sets, it's the fashion of having the front all screen - so no room for forward facing speakers. But then they want to sell you a 'sound bar' or other such overpriced rubbish.
I've yet to see any LCD which can match a really good CRT for flesh tones.
But don't know if a oLED can - I suspect not either.
Of course very few indeed have ever seen TV on a Grade 1 monitor.
The TV in question was a somewhat budget one, just nasty in the sound department.
I once opened an LCD monitor that claimed to have built in stereo sound to find a pair of 1" speakers on the back! I doubt it put out more than 50mW. Good enough for bleeps.
NT
Like bulging caps or short / open circuit diodes on the PSU board (I did one yesterday). ;-)
You don't really need to know much about tellys these days (as you probably couldn't do much d-i-y with the LSI / logic boards) but often the more basic bits mentioned above.
Because it contains little in the way of valuable 'scrap'.
There is a skip for such things at your local recycling centre. ;-(
Yup ... and why most people have sound bars or pipe their TV sound though their HiFi or other speakers.
If it had I think you would have had a picture but fading brightness from one side to the other.
Could have been a dry joint ... ?
I have a large plasma monitor up on the bedroom wall that must have cost someone a few quid when new. Whilst it still works, the top of the screen has some noise on it but it still makes a good panel heater. ;-)
Cheers, T i m
Don't use the TV's own sound system. Take the line out or optical and feed into a decent sound system.
Early TVs had the problem of the speaker magnet interfering with the cathode rays, so the speaker was placed on one side or the other right at the back of the cube shaped cabinet. I think it could positioned on the right or the left side so it wouldn't be against the wall. I suppose the TV engineer would ensure it was on the correct side if he could be bothered, at the same time as fitting the right coils for the TV channels (unless this was done back at the shop).
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.