PING Bill Wright - interference or TV fault?

[Steve]

Our five-year old Panasonic TH-42PX80BA plasma telly has, just this morning, started showing 'moving sparkly lines' (crap description, I apologise) and I was wondering if it's likely to be interference of some sort or the TV itself going faulty.

We have a Sky+HD box connected (though we don't subscribe to the HD service) via HDMI and the lines are visible both when viewing through the Sky box or when using the TVs own internal Freeview tuner.

We have a coax taken from the Sky box's RF2 output to two other TVs in the house (so that they can either use their own tuners or watch what the Sky box is showing) and the lines are *not* visible on either of those TVs, either via Sky or Freeview - only the main TV (which is in the living room) is affected.

The following two photos show the lines quite clearly. I paused the Sky box for clarity but the lines were still moving even with the picture on pause:

Any ideas? We're in Preston, Lancs - Granada Region, Winter Hill transmitter.

[Andy Burns]

The photos look nothing like the interference you'd get from DVB-T or DVB-S, my first though was a loose HDMI connector, but you seem to have eliminated that by using the internal tuner, I's say the problem is with the display circuitry of the TV, you could try a different source such as VGA in from a PC or scart/composite but I suspect it'd have the same fault.

If percussive maintenance has any effect on the lines I'd look for a dry joint or loose connector inside if you fancy having a go yourself (assuming it's out of warranty by 5 years old).

[Steve]

Thanks for that quick reply Andy. I'll give the percussive maintenance a go, but if no joy I'll hunt out the paperwork because I'm sure it's somewhere around 5 years old - but we took out a 5-year warranty as well when we bought it from Richer Sounds. I'll probably find that the warranty ran out last month but hey-ho, worth a try. Thanks again sir :')

[alan]

It looks as if the faulty lines have been shifted to the left by 64 (ish) pixel positions. The white lines come from the shirt and badge. The light blue displaced lines fit the channel logo

Possible a line sync problem or maybe a 50Hz source and 60Hz display, or visa-versa.

Try turning the TV off at the mains plug rather than putting it just into standby. This sometime resets crashed software/firmware.

[Steve]

Ok Alan, worth a try - thanks very much

[Dave Liquorice]

So they are not on the recording or incoming data stream. I'd reseat all the cables, especially if they haven't been disturbed for a while (while > 1 year). Though as you also say that the internal freeview receiver also exhibits the problem I don't hold out much hope of an external cable fault.

The full power down of the TV and all other boxes/TV's connected might cure it. HDMI works well but is rather too clever at times and can get confused. I had and audio L/R swap that I couldn't clear without a full power down of everything, I might even have had to unplug everything, power cycle each unit then plug everything back together.

As a last resort you could try a factory reset.

[michael adams]

The simplest way to eliminate interference would be to try an external source DVD etc. , using a known good lead, be it HDMI, SCART or whatever. If you get the same fault showing up on the DVD then it's the set. Otherwise not.

The output of the internal Freeview tuner is still dependant on the cable which is feeding it and so different sets connected using different cables might not exhibit the same fault, even if connected to the same source.

michael adams

...