Converting old GEC radio for aux-in

[Andy625]

I hope I've picked the right forum for this question - this is my first post on this forum. I have a GEC Starfinder radio dating from around 1979, which still works fine. However I would like to convert it to take an input from an mp3 player, and effectively use it as a speaker.

The radio has a 5-pin din socket on the side which I remember using to connect it to an old radiogram many years ago, so that the radio played through the speakers of the radiogram. I was wondering if the pins in the din connector can be configured such that the connection goes the other way, and whatever is connected to the din connector is played out through the radio speaker? So that its an input connector rather than an output?

Alternatively, I would be happy to sacrifice the headphone socket to be a 3.5mm input connector.

I know a little about electronics, but not enough to figure this out on my own. Can anyone give me any advice, or point me towards someone that may know how to do this?

[crackle]

You may find that it will work already with a standard stereo jack to 5 pin DIN cable. The output which you used with the radio gram probably came from before the volume control so that the signal was the same regardless of where you set the radio volume. So injecting a signal back into the same point will go through the volume control to the amp and you will be able to adjust the speaker volume using the radio's volume.
Depending on how the DIN socket is wired you may or may not need to bridge the left and right channels together to make mono for the radio amplifier.
You will need to tune the radio to a quiet part of the dial.
Can you post a close up photo of the inside of the radio showing the connections on the back of the DIN socket (may not be possible if it is mounted on a printed circuit.)

Mike

[newlite4]

Try connecting to pin 3 (left channel in) and pin 5 (right channel in), these should be the aux inputs along with pin 2 which is ground.
Neil

[KeithsTV]

I have an ITT Europa 100 radio dating from 1974. It has a DIN connector for connection to a tape recorder but I'm sure that pressing two of the push buttons down simultaneously disconnects the tuner and allows it to be used as an amplifier using the L & R input pins on the DIN connector.

Keith

[Andy625]

Thanks for all the replies - that is very interesting. I didn't realise that there may be a chance that it wouldn't need any wiring changes. I will see if I can get a photo of the inside of the set tonight. I didn't realise that you could buy 5-pin din to 3.5mm jack leads. If all else fails though, I think I may have the lead that I would have used for the radiogram somewhere at my mums.

[Andy625]

Just had a quick search, and found numerous 5-pin din to 3.5mm jack leads on Ebay. As the radio is obviously mono, would I be best buying a 5-pin din to 3.5mm mono plug, or would it not make any difference?

[paulsherwin]

The MP3 player will have a stereo jack socket so you will need a lead to match this. The radio will have the L & R connections bridged internally, either directly or with resistors.

[Andy625]

That's great. Thanks for your help!

[Andy625]

Here (hopefully) are some photos of my radio. I'm afraid they're not brilliant pictures, but hopefully you'll be able to see enough.

I've ordered a lead which should be here later today, so we'll see what happens.