grundig 4870

[melinx]

If anyone thinks that the reception on FM on their Grundig 4870 is rubbish, they could be right.
On my 4870 rds V there was no connection between the aerial input point on the FM board
( pin 1, which is the pin nearest the aerial input socket ) and the aerial input socket.
I bought a 4870 rds C ( an earlier model ) from Germany on Ebay and found that this was exactly the same !!
The circuit diagram says that there should be a connection !! the radio works after a fashion due to the close proximity of this pin to the aerial socket.
Making the connection on both sets as per the circuit diagram and bench testing with a signal generator showed that the sensitivity was improved from 20 microvolts to 2 microvolts, a tenfold improvement !!
Back in the car, the crazy behavior on RDS and TP was radically reduced
I wonder how many were produced like this ?

[jonnybear]

our green carlton

had a mint reception everything works but now i had to remove and swap it with the one in my room, cos the reception is poo or non existent some times.

I wonder if its got the same problem ?

i dont fancy taking it apart ?

hmm

[melinx]

All that needs to be removed to get at the aerial connection is the bottom plate which just clips on.
You may need to break the guarantee seal
Unfortunately I don't have a camera to show how simple it is, maybe HMK or von-opel could help ?

[jonnybear]

took the plate off and it looks like a greek salad picturs would be appreciated i will post one tomos

[Murph]

I'll have a look to see if I have an old unit - I'm sure I have one that's code locked somewhere.
If I can find It I'll take the cover off and take pics.

[jonnybear]

found a piece of carlotn history

took radio out in my dippy, found a sticker on it and a number

" radio signal cutting out especially on 97.3"

H . Evans and phone number, im tempted to call it!

cars only had two owners, sooo i wonder :O

[melinx]

If anyone thinks that the reception on FM on their Grundig 4870 is rubbish, they could be right.
On my 4870 rds V there was no connection between the aerial input point on the FM board
( pin 1, which is the pin nearest the aerial input socket ) and the aerial input socket.
I bought a 4870 rds C ( an earlier model ) from Germany on Ebay and found that this was exactly the same !!
The circuit diagram says that there should be a connection !! the radio works after a fashion due to the close proximity of this pin to the aerial socket.
Making the connection on both sets as per the circuit diagram and bench testing with a signal generator showed that the sensitivity was improved from 20 microvolts to 2 microvolts, a tenfold improvement !!
Back in the car, the crazy behavior on RDS and TP was radically reduced
I wonder how many were produced like this ?

The red wire is the one to add.

Be warned though, this will not cure the dreaded sudden cutting out on FM, but it radically improves the ability to receive FM in low signal strength areas

[Winky]

Has anyone any ideas or actually established what causes the drop out?

Now the weather is warming up (at last) mine is dropping out more & I'm still not convinced its as something as a dodgy connection thats getting hot & 'buckling' & then going back to its original shape when it starts to cool down thus making connection again. It rarely happens to mine during the winter/colder weather making me think this.

I must point out, if my post doesn't give it away, I'm now electronics genius but common sense seems to point this way.

[melinx]

I would be delighted to know the answer

http://totalcarlton.com/forums/index.php/topic,8167.msg67953.html#msg67953