Starting on Monday, the picture is breaking up across all the channels. When it's switched on, a message pops up saying the antenna cable is short-circuited. It's been saying that ever since I got it on BBC1, but hasn't affected anything. I haven't moved or changed anything. All is fine on the TV it's connected to, and on the the other humax I use. Please help!

As I recall the 9300 has an option to power a masthead amplifier via the aerial IN socket. If you have no such device the aerial resembles a short circuit to a DC voltage hence the message. You can turn this option off in the set-up menus. But it does no harm as the Humax simply shuts off the voltage anyway.

As for the other issue. How is your aerial fed to the Humax and the other devices you have? Do you have anything connected to the Aerial OUT of the affected Humax? If so does that display any picture break up? That would indicate if the feed to the Humax is OK or not.

Try swapping the aerial lead round with one of the other units, depending on how it is wired up, to see if the fault follows the lead or stays with the Humax.

What signal strength and quality reading do you get on the Humax?

How have you got it connected to the TV? Have you tried a different cable?

Thanks for your reply. The aerial comes straight from the aerial on the roof to the humax, which then has a lead coming out of it to connect to the TV. The TV picture is absolutely fine, but the humax freezes, goes slow, and makes that horrible sqeaking noise every now and then.

What signal level and quality readings do you get? Different receivers react differently to low or high signal levels. If the level is very low it might be the Humax is struggling but the TV copes better.

Equally too high a signal can cause problems of overload in the tuner.

I'm assuming it should be the same as the other humax, which is absolutely fine, but will check once I get home.

There appear to be two separate issues with the 9300T.



In that case make sure the Antenna Power is off.
MENU -> Installation -> Antenna Power


As chrisjr state this could be caused by the strength level being to high. Unfortunately the Humax strength metre does not indcate how much over 100% it is once it reaches 100%. To be on the safe side it should be below 100%.

Another possibility is that you are tuned into the wrong BBC mux and the weather has only now become such that you cannot receive a good signal. Did you manually tune it in the same manner that you do/did for your parents' 9150T?
http://forums.digitalspy.co.uk/showt...3320&highlight=
And are you sure that you chose the best transmitter for the aerial you have installed?

It could also be that a cable has deteriorated and the BBC mux happens to be the first to suffer.
You could try comparing the readings of your two Humaxs but as there is no standard for the strength metres what they display could be different just because they are two different boxs. To be sure that it is not a cable issue would it be feasible to swap you 2 Humaxs box over so they are instead using the other’s aerial cables?

I got home and checked the signal and that was 100%. The quality, however, was jumping around all over the place. I fiddled around with the cables, but the problem persisted. Having just checked again, it finally seems to be behaving itself.

In answer to your tuning question, I'm pleased to say I use the automatic version on mine.

As always, I'm very grateful for the assistance given on this forum, and shall bear your comments in mind in case it happens again.

There is a peculiarity with the 9300 where the signal strength reads 100% with Antenna Power switched ON, the reading is not real.

If you turn the antenna power off and the signal level stays stuck at 100% with the quality all over the place then that could be a sign of too much signal. This can cause overload in the tuner front end which generates loads of interference effects, seriously degrading the picture.

The TV should also be reading up near the 100% mark as well as a comparison.

Fortunately that is easy to cure with a simple attenuator in line with the aerial feed to drop the signal level a little. For example

http://www.maplin.co.uk/p/aerial-attenuator-6db-bw59p

If however the signal is too low that is rather harder to cure. Depending on what is causing the low signal. It could be an inadequate aerial, damage to the aerial, the aerial shifting in the wind, damage to the cable or a poorly terminated plug