Cable Arcing??

mjsmyth

I was out in a friends house today and he asked me to have a look at his Sky+ as only one of the tuners was getting a signal.

To see whether it was a cable/lnb issue or tuner issue, I uncrewed both f-type connectors at the back and was going to swap them over when I noticed that one of the cables seemed to be missing the inner core.

On closer inspection, the core was sitting in the lnb input and all around the imput had turned black and a tad brittle. The cable was also blackened as was the inside of the f -type connector.

It would appear to me that when the cable was made, the inner core must have got snipped and over time broke. It would then seem that the a certain amount of arcing took place.

How much power goes down a cable to the LNB? Apart from possible damage to the sky+ box, is it possible it could have been a greater risk to the house?

Anyway, I remade the cable and all is good in tv land.. for the moment at least.

MJ

Tony

mjsmyth wrote: »

How much power goes down a cable to the LNB? Apart from possible damage to the sky+ box, is it possible it could have been a greater risk to the house?

MJ

Very little in the milliamp range, sounds like water ingress.

mjsmyth

Water ingress? Hmmmm...

There was no noticeable water within the cable when I remade it. I will be damned if i am going to get up on his roof and hang out of his chimney to check the connections on the dish.

As it happens, I that who ever installed the dish for Sky, installed it very very close to the roof tiles. From where I was looking, it looked like the LNB was actually resting on the roof tiles..

As for my friend, hopefully it won't rain too badly anytime soon!

Thanks Tony.

MJ

Tony

My pleasure, its probably a small amount entering the cable over a long period.

mjsmyth wrote: »

Water ingress? Hmmmm...

There was no noticeable water within the cable when I remade it. I will be damned if i am going to get up on his roof and hang out of his chimney to check the connections on the dish.

As it happens, I that who ever installed the dish for Sky, installed it very very close to the roof tiles. From where I was looking, it looked like the LNB was actually resting on the roof tiles..

As for my friend, hopefully it won't rain too badly anytime soon!

Thanks Tony.

MJ

jonnygee

I had this problem a few times with one downlead, I came to the conclusion that it was being caused by a chemical reaction between the copper in the cable and the alloy in the F connector or lnb input, The fact that this lead was actually cctv cable probably didnt help.