Aerial cable not working after new faceplate added to existing cable

[Mike Turbutt]

Hi all,
Just had a complete rewire done (excellent job) but after they added a new faceplate to the aerial cable, I get no signal on the TV. Sadly the old faceplate is gone in the trash so I can't put it back.
I've reconnected the cable several times to ensure no shorts and I've continuity tested the faceplate to ensure it's not a short fault there either.
The weird thing is that if I pop a screwdriver on to the center pin at the back of the plate, I get a perfect signal. The moment I take it off, the signal drops again. I assume this means the screwdriver is acting as an aerial in this case.
I seem to remember that the old socket had some kind of additional components "under the hood" so to speak but the new plate is a plain coax connector.
Any advice would be most welcome as it's driving me bonkers.
Many thanks in advance,
Mike

 

[MJPD29]

Sounds like a poor connection onto the faceplate, have you definetly connected it properly with the inner core and outer core clamped properly? Failing that is it connect properly at the other end? Of is it simply a dodgy faceplate

 

[telectrix]

check continuity from the back terminals to the front socket. also, if you get a good signal from a screwdriver, it could be that the old socket had a built in attenuator to reduce a too strong signal.

 

[Mike Turbutt]

Hi Matthew and thanks for getting back so quickly.
I'm confident that both inner and outer are connected correctly and clamped well. I have tested for shorts and found none.
I haven't checked the aerial end as it's on the roof and was working ok with the old faceplate which is the only thing that changed.
I should note that the aerial cable is VERY old and probably needs replacing. If I can't sort this issue out, I'll be investing in a new aerial and cable...it wouldn't hurt.
My sparks suggested a dodgy faceplate and offered to swap it out but I've continuity tested it and it seems ok. Probably worth a shot though.
Just odd that it works as soon as I touch the center pin with a screwdriver.
Thanks again.

 

[telectrix]

could be a dry joint and when you apply the screwdriver, it makes the connection.

 

[Mike Turbutt]

check continuity from the back terminals to the front socket. also, if you get a good signal from a screwdriver, it could be that the old socket had a built in attenuator to reduce a too strong signal.

Hi telectrix, I just continuity tested rear plate to front connector and it's all perfectly isolated. Definitely not a socket issue but thanks, worth checking.
Just spotted your note about a built in attenuator. It definitely had something in the old socket...not just a straight connector. Didn't know what it was though but now I'll try to get one to test.
Many thanks for that valuable nugget!!!

 

[tiptoppauly]

If you have a mast head amplifier attached then it will need a power supply unit to power it. This could be the part you are missing?

 

[Mike Turbutt]

If you have a mast head amplifier attached then it will need a power supply unit to power it. This could be the part you are missing?

Thanks for the tip. The only thing that's changed is the wall plate but I suspect that the old one was attenuated (I remember seeing "components" in the old plate that was thrown away) so I'm going to try an inline attenuator first and see what gives.
Many thanks.

 

[GeorgeCooke]

All of this is a perfect example of why you should not use an electrician to do an aerial installers job. They don't know enough about the subject. Also why you should not throw away old components till the new ones are working. It is unlikely those components were an attenuator. More likely a filter or perhaps isolating (safety) components.

Your best bet is to get an aerial installer involved who will have the correct test equipment to measure signal level, bit error rates etc. Hopefully he will also have the socket with the correct components on it.

 

[Mike Turbutt]

All of this is a perfect example of why you should not use an electrician to do an aerial installers job. They don't know enough about the subject. Also why you should not throw away old components till the new ones are working. It is unlikely those components were an attenuator. More likely a filter or perhaps isolating (safety) components.

Your best bet is to get an aerial installer involved who will have the correct test equipment to measure signal level, bit error rates etc. Hopefully he will also have the socket with the correct components on it.

100% agree with everything you said George. I made contact with a local aerial chap yesterday afternoon and awaiting his call back.