We have just had a telly a panasonic delivered but the picture when watching through the sky box is rubbish. Alright through TV aerial both digital picture and analogue Help pls I have had a look through the fault finding in the book and been on their web site but neither gave any help
New lead would probably cure it, unplugging it and plugging it back in a few times might too.
the contacts on cheaper leads corrode over time, if it's being used then it won't corrode at the precise points it's making contact so will work for years. use it on different devices after that time and they make contact at different points so you get a bad connection.