Hi all
Most annoying, the telly is displaying diagonal stripes/bands about 1/2" wide alternate red and green, sort of scrolling away from bottom right hand corner. Sometimes they emanate from the corner, but sometimes the direction seems to reverse towards the corner. The set is Panasonic CRT model not the latest of course, but an anyone advise the cause and possible solution (other than replacement).
TIA
Phil
Is this phenomenon present on all channels?
Steve
Mains hum? Try moving mains and signal cables apart.
Just a thought.
That description sounds a bit like RF patterning, a strong local signal can do it of co-channel from a long way away of the atmospheric condistions are right.
What are you watching? DSAT, DTTV, DVD/Video if so how are they connected to the TV. How many boxes have the aerial lead looped through them? Is it always there? Is it on all channels?
That sounds like poor scart leads. you need decen quality, seperately screened leads
"Dave Liquorice" wrote
Thanks Dave
I did try a bit of deduction/trial and error. Seem to think that this problem was evident on all channels/sources. I have Sky (freesat only), Freeview, DVD and terrestrial. The thing is I haven't altered anything! Freeview, Sky and DVD are scarted into a multi box, then single scart up to TV. Selection buttons on multi box dictate which device the TV displays - bit clunky and non-remote control but it works. Is it possible or likely that a neighbour's aerials/satellite dishes would interfere with our reception? Can't see why it should, but they have even more aerials, dishes etc than me (not that any of them have just been erected).
Phil
Phil
"Fray McBentos" wrote
As stated in previous response, I don't believe anything has changed, but I guess I'll start unplugging stuff to see where the fault lies.
Thanks FrB
Phil
is it fixed or moving?
If fixed might be a magnet in the neigbhorhood.
Fixed by removing magnet, and switching TV on and off a few times to de-gauss.
The OP says srolling and the angle changes over time.
Magnets or magnetised shadow mask tend to produce wrongly coloured patches rather than stripes or bands.
on 05/03/2008, TheScullster supposed :
That, combined with your additional comments suggests to me it might be an earth loop. One the the items connected has some small current travelling along the outer screen and that small current is inducing interference onto the cores of the cable which is what is appearing on the screen. Pull things out one at a time until the problem disappears.
The usual solution is to cut through the outer screen to break the loop at the end of the cable closest to the output.
The TV's permanently-on internal (analogue?) tuner signal is being sent out of one of the Scart sockets and is coupling and interfering with signals fed from your external Scarted equipment when in AV mode. You should be able to disable this output in a TV setting somewhere, or get individual core screened cables, or snip wires (extreme), or tune the internal TV channel to somewhere quiet (which it may have been up to now....)
Which normally causes hum, hum on a TV screen is a broad bar the rolls vertically up or down, can even be almost static. Most if not all set top boxes, DVD, Video machines etc are double insulated so loops are quite a hard (but not impossible) to create as there is no mains earth to complete the loop.
I quite like Adrian C's suggestion, worth investigation. Decent quality individualy screened cables should prevent it but some SCART cables are just a bundle of cores with a single overall screen, crosstalk heaven...
More like beats, IWHT
Local oscillators of two different devices interfering with each other
That sounds like RF interference. Another signal is cross modulating with the wanted one and producing this pattern. It could be from another TV transmitter and being picked up as a result of unusual propagation conditions.
In message , "Dave Plowman (News)" writes
Or it could be the UHF output of one of your boxes. Try moving them one channel.
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