No radio signal

[mrtibbs]

Hi all. I have recently bought a Skoda Fabia 1.9Tdi estate for our sons first car. It is going into the local garage to have new rear brakes and a rear shocker fitted. There are a couple of other things that need attention however and one of them is the radio not working. I have removed the roof aerial and found the there is a flat spring like piece of metal on the circuit board that looks as though it should be in contact with the pin that stcks down from the aerial mast. Should this touch the pin or not? I have tested it with a meter and when the pin is in contact with the spring piece I have continuity from the thread of the aerail mast to the outside of the aerial connector into the radio, this seems to be wrong to me. Can anyone offer any advise please?

TIA

 

Keith

[Gobsheene]

Hi Keith, 

 

I cant help specifically with the aerial base, but with Co-Axial cable, the outer must not touch the inner so as not to compromise the signal. If you're testing continuity i'm sure you're aware of this already! 

 

Did you check all connections on the back of the radio 1st? 

 

Could be it's had an after market stereo fitted by previous owner and when they put the standard one back in they didn't reconnect the aerial. 

 

It's easily missed sometimes  

[mrtibbs]

Thanks for the reply. Yes I did check that there was no short circuit between cores, it is good. All connections are OK and present as far as I can tell. I have offered up another stereo to check that it is the signal and not the unit that is at fault, same results....

I will need to have another look as it was getting dark when I was looking last night.

thanks again

 

Keith

[mrtibbs]

Any other ideas please?

 

Keith

[mattievrs]

Standard radio or aftermarket?

[mrtibbs]

Standard radio or aftermarket?

It has a standard (I think) stereo with Skoda printed on the front panel

[AndyPandy]

What resistance are you getting ,when you say you are getting continuity?. Multimeters normally have ,a continuity range,and 3 or 4 ohm ranges.Continuity is normally expected to be up to about  50ohms or less,Ohm ranges can be up to 20 Mohms(20,000,000 ohms).

As the  aerial rod connects to an electronic amplifier,it is possible  a meter will show  a value on your meter. Try a piece of wire acting as an aerial, where the aerial lead  connects to the aerial base,and also at the input of the aerial socket on the radio.I would expect to receive some strong signals which would prove the radio,and the lead.Make sure that the spring is making contact with the pin you mention in the aerial base. Also the 2 self tapping screws,and amplifier base are sealed with silicone rubber to stop water ingress onto the printed circuit ,and its components. When I had problems with signal strength, I found an open circuit where the aerial cable meets the socket ,at the aerial end,possibly caused by somebody pulling on the cable to disconnect the socket.

Edited 19 April, 2014 by AndyPandy

[gfwc]

The radio doesn't work on mine either. With both the standard unit and aftermarket unit.

On my other Fab estate, I got really good signal with the same stereo.

I'm getting sweet FA at the moment.

[Ryanfsr]

I've read somewhere here before that the PCB directly underneath the aerial suffers from water ingress which leads to corrosion.

About a £30 part to replace I believe, but involves partially removing the headlining inside the car to remove it.

Going to give this a shot myself sometime soon as my radio is pretty shocking to say the least

[mrtibbs]

What resistance are you getting ,when you say you are getting continuity?. Multimeters normally have ,a continuity range,and 3 or 4 ohm ranges.Continuity is normally expected to be up to about  50ohms or less,Ohm ranges can be up to 20 Mohms(20,000,000 ohms).

As the  aerial rod connects to an electronic amplifier,it is possible  a meter will show  a value on your meter. Try a piece of wire acting as an aerial, where the aerial lead  connects to the aerial base,and also at the input of the aerial socket on the radio.I would expect to receive some strong signals which would prove the radio,and the lead.Make sure that the spring is making contact with the pin you mention in the aerial base. Also the 2 self tapping screws,and amplifier base are sealed with silicone rubber to stop water ingress onto the printed circuit ,and its components. When I had problems with signal strength, I found an open circuit where the aerial cable meets the socket ,at the aerial end,possibly caused by somebody pulling on the cable to disconnect the socket.

Thanks for the reply Andy. I will try your suggestions maybe at the weekend when our lad is not using it. I had connected one end of my meter lead to the aerial on the roof and the other lead to the aerial lead that connects to the radio in the dash. I was listening for a bleep rather than noting any values :( One thing that struck me as strange was the fact that the Bleep was from the outside ring of the aerial connector and not the centre pin as I would have expected. Is this correct?

Thanks

Keith

[AndyPandy]

Hi Keith,

It is a bit hit and miss,because all meters have different characteristics , continuity setting is really for house type cable checking,as a intact wire or an  open circuit! OK for checking aerial cable continuity ,but with both ends unconnected. Try and get to both ends to do this check.If cable seems OK it more than likely is the aerial amplifier at the base of the aerial mast.Did you find any white corrosion when you checked it? 

[mrtibbs]

Hi Andy. Thanks for the help I am an engineer and am using an excellent digital DMM to carry out the testing, just getting confused with the readings that I am achieving with this. I had the radio end open and the other lead into the socket of the aerial mount on the roof. I realise that the amplifier is in circuit with that arrangement but at least I know that I have a path from the roof to the radio albeit not the way round that I expected. I have bought a replacement aerial from Ebay so as soon as that arrives I can test that one as I believe that the fault lies with the amplifier now.

Thanks again

 

Keith

[mrtibbs]

Ha, just when you think that you have the fault nailed, it kicks you in the teeth :( I popped out earlier when the replacement aerial arrived and fitted it, same result, just a mushy noise. I have quickly (although maybe not effectively) tried to connect my meter leads to the radio end of the aerial cable and also to the connector that joins onto the roof mast lead. No signal..... Looks like the coaxial cable is open circuit? Don't know how that would have broken but I will try again tomorrow with some help from son to see if there is continuity or not.

Peed off now :(

 

Keith

[sepulchrave]

Jeez, to check for continuity throughout the entire length of the cable just twist the core and screen together at one end and measure between the core and the screen at the other, easy one man job taking two minutes.

[mrtibbs]

Twisting together a moulded plastic fitting, while still leaving it in a condition that it can be reused isn't actually that easy, maybe you have a suggestion to cover that as well?

 

Keith

[sepulchrave]

Twisting together a moulded plastic fitting, while still leaving it in a condition that it can be reused isn't actually that easy, maybe you have a suggestion to cover that as well?

 

Keith

 

I do, just jam something conductive into the plug between the pin and the shield at one end and check for continuity at the other.