Becker Aux In Wiring?

[scoot]

Becker radios have a DIN socket in the back for plugging in the optional cassette player.  People have also sold setups for plugging in an IPOD, etc.   Does someone know the wiring scheme for doing this?  I would like to work on a bluetooth interface and am exploring possibilities...

[Peter van Es]

Why do people not look through the Tech Manual... look and ye shall find: http://www.sl113.org/wiki/Electrical/Ipod

Courtesy of myself!

Peter

[scoot]

Hi Peter -

Thanks, I wasn't expecting to find that in the technical manual.  I have seen those diagrams at other sites, and I'm still confused.

Considering the 7 pin Stereo version, here's what I see:

Pin    Purpose
1      Output tuner R  (what do I do with this?  does that mean that this is the input for a different amplifier if I want?)
2.     Ground Chassis (I understand)
3.     Input amplifier R (I inderstand that this is the output from my device going to the R channel of the amplifier)
4.     Output tuner L  (see item 1)
5.     Input amplifier L  (see item 3)
6.     Ground Audio  (this is a common ground for pins 1, 3, 4, 5, and if I want to run an auxillary device through my radio then I would have the left channel wired to pins 5 and 6 and the right channel wired to pins 3 and 6, right?)
7.     Off / On  (I'm assuming that if you short this to ground it tells the radio to not be a radio but instead to be an amplifier for the aux device - is that correct?)    (Or is this 12 volt power to the auxilary device?)

The Becker Stereo Cassette player that I have has the 7 pin din plug.  It does not have a separate power wire (or it is missing).

Is pin 7 the power supply?

If so, how does the radio know to shut off when you stick a tape in the cassette player?

thanks
Scott

[scoot]

Also, the diagram shows 1 - 3 shorted    and   4 - 5 shorted.    I don't understand this either.
thanks
Scott

[Peter van Es]

You need to understand the normal functioning of the radio to understand how the DIN plug works.

The radio has a separate tuner and a separate amplifier. The tuner output is fed into the amplifier input normally, and the radio plays via the speakers.

Hence Tuner output L+R. And amplifier input L+R. When you wire in an auxiliary device with a 3.5mm plug, it uses a socket that disconnects the normally shorted Tuner R - Amplifier R, and Tuner L to Amplifier L when the 3.5mm jack is inserted. Thus allowing you to connect ipod output to amplifier input. When the jack is removed the shorts are made again. Hence the need for a special 3.5mm socket, with a short as default function.

Audio ground is separate from battery ground. I'd have to look at whether the ON/OFF is just a switched +12v circuit.

Peter

[Ron]

OK, I've been working on radios and TVs since 1960.  I'm not the smartest, but I do have history. 

I agree with Scoot, I don't understand the shorts between 1 and 3, and 4 and 5.  I think they should be removed if you wire in an iPod with this.  Two cables are needed.  I would make up a male to male (both 3.5 mm plugs) cable, one side goes into the iPod the other to a socket to be installed in dash area.  The second cable needs a female socket  and a DIN plug to the radio.  This socket will feed through the tuner to the amp, when the first cable is out.

Summary:

1.  Double male, from iPod to female socket mounted under dash.

2.  DIN connector to female socket with all 4 signal lines.  The L and R DIN tuner lines go to the female socket and the L and R socket lines go back to the DIN amp pins in the radio.

Plug in the cable 1 into the socket, tuner is disconnected and iPod plays.  Unplug cable 1 from socket and socket contacts feed through the L and R tuner signals to amps.

Same goes for mono set up, the short between 1 and 2 needs to be removed.

You will not be able to use a male plug with the DIN connector, as it will not perform the feed through function.  You could use a male plug with a box with a switch, but I think the female socket is more elegant. 

Wiring as shown will allow tuner to play WITH the iPod, and you hear both.  It would work if you tune off station and your FM or AM band is quiet.

I have not tried any of this, but it is on my list.  I wanted to get my car running first.

BTW I purchased a spare lighter.  I intend to gut the lighter, and put my socket in the center of the lighter knob, just plugging in the iPod right next to the radio.

(the ash tray is to become a holder for the gate clicker.  Or maybe I'll turn that wooden tray between the seats front to back and use the ash tray hole for seat belt buckle storage.)

Ron

[scoot]

The radio has a separate tuner and a separate amplifier. The tuner output is fed into the amplifier input normally, and the radio plays via the speakers.

Hence Tuner output L+R. And amplifier input L+R. When you wire in an auxiliary device with a 3.5mm plug, it uses a socket that disconnects the normally shorted Tuner R - Amplifier R, and Tuner L to Amplifier L when the 3.5mm jack is inserted. Thus allowing you to connect ipod output to amplifier input. When the jack is removed the shorts are made again. Hence the need for a special 3.5mm socket, with a short as default function.

I'm still confused.  I understand that there is a separate amp, and that the tuner feeds into the amp, and that the cassette DIN plug can also feed into the amp.  I _think_ you are saying that the DIN plug itself shorts 1-3 and 4-5 when you are not using the cassette, and un-shorts them when you are using the cassette, thus disconnecting the radio output from the amp input.   I also understand how that could be made with a little box around the 3.5 mm socket that performs this function when a plug is inserted into the little box.  What I don't understand is this:  If plugging something into the plug is supposed to un-short 1-3 and 4-5, then why does the radio work at all if you have NO DIN plug pluged into the back of the radio?   Or is the radio clever enough to know that if you have a DIN plugged in that it should use the DIN contacts to decide if the radio still gets connected to the amp?   

[Ron]

Hi Scoot, when I was working on one of my first Becker repairs, I left the DIN plug out while changing the dial light.  The radio worked, but very low volume.  That plug must be in to connect the tuner to the amp for it to work at full volume.  Pull yours out and you'll see 4 male pins.  Those are the L and R connections we've talked about.  When left off, the only connection between the tuner and the amp is accidental and via the 12 volt power bus.  There should be no signal on the power bus, but I've seen it happen on Beckers.  With a modern radio, you would even get the low volume with the plug out, but these radios are old, and low tech by today's standards.  (Don't get me wrong, I love them.)  So does this make sense?

I am glad Peter posted the connection diagrams, and they will work as posted.  It's just that the tuner must be tuned off station if you don't want to hear the radio while the iPod is on.  On one of my Beckers, it is easy to jiggle the pushbuttons to where the band switch is between AM and FM and the tuner quits.  So I could listen to the iPod with that radio, and tuner/amp connection intact.

When Becker connected the external tape player, it is possible that they could have turned the tuner off via the DIN plug, but not on any Beckers I have seen.

Ron

[scoot]

Hi Scoot, when I was working on one of my first Becker repairs, I left the DIN plug out while changing the dial light.  The radio worked, but very low volume.  That plug must be in to connect the tuner to the amp for it to work at full volume.  Pull yours out and you'll see 4 male pins.  Those are the L and R connections we've talked about. 
...
I am glad Peter posted the connection diagrams, and they will work as posted.  It's just that the tuner must be tuned off station if you don't want to hear the radio while the iPod is on.  On one of my Beckers, it is easy to jiggle the pushbuttons to where the band switch is between AM and FM and the tuner quits. 

When Becker connected the external tape player, it is possible that they could have turned the tuner off via the DIN plug, but not on any Beckers I have seen.

OMG!!! Yes, it is perfectly clear now that I see that the little plug covering the din plug isn't just a cap.  So I believe that the Cassette player and the available IPOD interfaces both un-short  the radio -> amp connection when they are engaged, and short them when not engaged.   Yippee !!!  I get it.  The critical part of "getting it" is seeing that the little cover plug on the DIN has the 4 pins.  THANK YOU Ron.  THANK YOU Peter.   Scott.