Old TV with built in tuner - where is signal coming from? 12 January at 10:26AM in Techie Stuff 10 replies 437 views

silvercar

Puzzle here.

trying to help a relating with an old Sony bravia TV.  sony bravia kdl-26v4000 (has built in digital tuner).

The picture quality has deteriorated- looks like the signal is weak or interrupted on the digital channels. The only cable connecting the TV is the power lead and one analogue Co axil cable going from the TV to the wall. There doesn’t seem to be an analogue signal being received. I tried changing the cable, while unplugging it, I’ve realised that  the digital channels still work. So where can the signal be coming from?? 

Any ideas to improve that signal gratefully received. Though my puzzle is where the signal is coming from when the only cable is the power lead? 

debitcardmayhem

The signal comes from the coax and your aerial. There are no analogue channels anymore they are all digital (not strictly true but that's a different scenario). There was a lot of nonesense spoken when we went to digital channels but most older aerials would still work with digital. Still you ptoblem could lie with your aerial alignment or the co-ax cable. Have you got another tv that works on the same socket?

Olinda99

Just to clarify, are you saying that if you unplug the coax aerial lead which goes between your TV and the wall socket, the digital channels still work, albeit with a not very good picture?

Then, when you plug the lead back again the digital channels continue to work but there is no improvement?

FYI -  that lead feeds the digital TV signal from your TV antenna on the roof into your TV. It used to feed analogue TV signals too, but these have been discontinued and there aren't any.

Neil_Jones

Its plausible that even without an external aerial (on the roof or wherever) the TV can still see something to receive, if the aerial socket in the TV is able to see something on its own, but this was more likely in the analogue days.  These days if you get anything at all like that the picture will more likely  look like an explosion in a Lego factory but I suppose anything is possible under the right circumstances.

debitcardmayhem

also you say old, if it's not been used for a while it may be doing a full retune , many channels change over the years

silvercar

Olinda99 said:

Just to clarify, are you saying that if you unplug the coax aerial lead which goes between your TV and the wall socket, the digital channels still work, albeit with a not very good picture?

Then, when you plug the lead back again the digital channels continue to work but there is no improvement?

Exactly this! 

Thanks for all your help. Still a mystery where it is picking up signal from when the cable isn’t connected.

DullGreyGuy

silvercar said:

Olinda99 said:

Just to clarify, are you saying that if you unplug the coax aerial lead which goes between your TV and the wall socket, the digital channels still work, albeit with a not very good picture?

Then, when you plug the lead back again the digital channels continue to work but there is no improvement?

Exactly this! 

Thanks for all your help. Still a mystery where it is picking up signal from when the cable isn’t connected.

Some aerials are terrible in terms of alignment, damaged cabling etc. No aerial however is magic and most aren't powered so its possible that the signal it can pickup just from its internal wiring is no worse than a poorly aligned aerial designed for analogue signals hence no material difference.

With our TV we can pick up some channels with no cabling, a little better with the aerial connector (its corroded to hell so no surprise little improvement) and totally different world if we connect the satellite cable to the freesat tuner that the TV also has.

These days watch most things via the internet/apps

Olinda99

When the antenna cable is disconnected, the TV is picking up (weakly) the broadcast signal using the metal socket on the back of the TV. Hence the poor picture.

The fact that plugging in the antenna cable makes no difference points to an antenna problem. Either try an indoor antenna if you have access to one, or get the TV man in to go up and fix the antenna problem on your roof.

silvercar

Olinda99 said:

When the antenna cable is disconnected, the TV is picking up (weakly) the broadcast signal using the metal socket on the back of the TV. Hence the poor picture.

The fact that plugging in the antenna cable makes no difference points to an antenna problem. Either try an indoor antenna if you have access to one, or get the TV man in to go up and fix the antenna problem on your roof.

It’s a flat in a small block. The aerial socket has possibly degraded. I would guess that the other flats may all be on sky or a Wi-Fi supported services and aren’t depending on this aerial, so aren’t bothered. This is only a bedroom TV, so probably easier to use a tablet to watch online and remove this TV, the main TV is connected to sky.

thanks for all your help.

fwor

If you want a counter-argument, you could take the view that your relative is almost certainly paying for the maintenance of the aerial distribution system as part of the common services of the building. If it's not queried with the company that does the building's maintenance, they will be paying for a service that they are not getting?

silvercar

fwor said:

If you want a counter-argument, you could take the view that your relative is almost certainly paying for the maintenance of the aerial distribution system as part of the common services of the building. If it's not queried with the company that does the building's maintenance, they will be paying for a service that they are not getting?

Thanks for this, I will mention it. The block is very small, so it maybe that there is no maintenance contract and repairs are made if and when notified.