Preserving the antenna motor / wiring the antenna to go up ONLY for FM/AM/Telephone (not CD)

[Jlaa]

I might be met with crickets on this one --- has anyone wired the antenna so that it only goes up for AM/FM/AMPS telephone and NOT CD?
I have a Becker 1432 system.....

I found reference to do doing this for the r129 with @Duh_Vinci on TFTSNBN

Antenna - manual up/down modification

www.benzworld.org

Basically I use the CD-changer input on my 1432 99.44% of the time when listening to the ICE, and there's no need to keep on cycling the antenna up and down. I thought about putting in an antenna up/dn switch, but this way (as done on the r129) seems more elegant.....

 

[Jlaa]

Unfortunately after further research, it seems that UNLIKE the r129 document mentioned above, the w124.036 500E does not have a separate turn-on-remote wire for the CD changer vs. the Antenna, as far as I can tell.

See diagrams attached. It seems that antenna control and amplifier control are all utilizing the same wire (+12v) and I cannot think of an invisible way to modify the wiring so that the antenna goes up only if AM/FM/Telephone were being used.

If there was was a separate wire to turn on the CD changer then yes I think it would be possible, but unfortunately there is not one that I can find.

So therefore perhaps the best way to control the antenna from not going up during CD changer operation is to:

a) get a spare dash wood panel
b) have Madera concepts cut another hole to make it have 8 holes
c) add a w124 antenna up/dn switch that basically cuts the remote wire to the antenna

Hmmmmm....

 

[darek_u]

Isn't it that the wake up signal to CD changer is sent through the bus cable? One of the wires in the loom is dedicated +12V wake up I think. Same for the amplifier part in the trunk. My car has BE1460 and no sound or bass system, just 2 part radio. Antenna is controlled directly from the head unit via dedicated wire.

 

[darek_u]

Alpine M Bus, 8 pin plug (CD changer plug), pin #7 (red wire) +12V wake up signal. This should be valid for CHM S600, 601, 611, 620. I don't know if it matches the output from MX3192 but it should if CHM 620 can be plugged into this interface.
This is what I found some time ago when researching the CD changer options.

 

[Jlaa]

Thanks!!!! I was afraid that the remote power lead was going through the bus cable. But that is good news —no need to add another switch on the dashboard.

 

[Sam SL]

@Jlaa, do a How-To once you decide on best approach. Best to not have to change out the wood panel. That sounds like overkill.

 

[Jlaa]

My plan is the take the +12V wakeup signal (pin 7 on the Mini-DIN cable) from the Alpine MBUS cable that wakes up the "CD Changer" and use it to drive a relay.



The relay will do the following:

• When the "CD Changer" gets +12V to wakeup ----> connect pin 1 at the antenna to ground (so that the antenna retracts)
• When the "CD Changer" does not get +12V ----> keep the factory connection at pin 1 of the antenna to let the car decide when to extend the antenna

I plan to use a breakout box so that that I don't have to hack into the cable to the "CD changer"





The next question is - do I use a breakoutbox for the 8-pin Mini DIN side or do I use a breakoutbox for the 15-pin VGA side? I am terrified of messing with any of the 8-pin Mini DIN connectors that go into the MX3192 or the tuner module for the BE1432 because I have found the MB componentry to be brittle, connectivity wise. So I will employ a breakout box on the VGA connector side.

I had to break out the multimeter to map out the pinout between the Mini-DIN and the VGA connector --- so here it is. Note that the Yatour "CD Changer" does not use Alpine's MBUS pin 3 (Bus Ground).



Comments / suggestions for improvement / different plan of attack are welcome! To be continued....

 

[darek_u]

Some more info for you, maybe helpful. Antenna current draw during retracting is little less than 3A, I remember it from bench testing, so the relay can be the smallest one you can find.

When the "CD Changer" gets +12V to wakeup ----> connect pin 1 at the antenna to ground (so that the antenna retracts)

I would connect pin 1 through NC part of the relay, when CD gets control signal it would simply cut off the +12V to the antenna forcing it to retract. When I was bench testing the antenna it only needed voltage to be removed from pin 1 to retract, no need for this pin to be grounded.
How to get the signal from pin 7 - definitely not from DIN plug, this would be a nightmare. Open it and you will see what I mean... I don't know about a breakout box but if they exist - why not. If you don't mind opening the MX3192 - this is the easiest way. See picture below of mine:



Can you see the red wire in the middle? I believe this is the one you are looking for.

 

[Jlaa]

Some more info for you, maybe helpful. Antenna current draw during retracting is little less than 3A, I remember it from bench testing, so the relay can be the smallest one you can find.

I would connect pin 1 through NC part of the relay, when CD gets control signal it would simply cut off the +12V to the antenna forcing it to retract. When I was bench testing the antenna it only needed voltage to be removed from pin 1 to retract, no need for this pin to be grounded.
How to get the signal from pin 7 - definitely not from DIN plug, this would be a nightmare. Open it and you will see what I mean... I don't know about a breakout box but if they exist - why not. If you don't mind opening the MX3192 - this is the easiest way. See picture below of mine:

View attachment 103674

Can you see the red wire in the middle? I believe this is the one you are looking for.

Hi @darek_u, Did you really measure 3A on pin 1 of the antenna motor? That sounds like a LOT!! Pin 1 is the "antenna/amp control" signal. As you suggest, I would run pin 1 through the NC part of the relay.

When you measured 3A, were you measuring pin 2 of the antenna motor (the power feed?)

Thanks.

 

[darek_u]

3A is the power feed current draw, I should be more precise.

 

[Jlaa]

Ok So I made a nice wiring adapter using the VGA connector breakout box and molex connectors to "steal" pin 7 (Acc) and pin 8 (Ground) from the Alpine MBUS interface.



And then I plugged it in between the Yatour "Cd Changer" and the cable --- and it worked! Yay!



But I realized something unfortunate --- No matter if the Becker 1432 is set to cassette, FM, AM, or CD, the measured voltage between pin 7 and pin 8 (ground) is always +12V! This means I cannot use pin 7 as a signal to automatically retract the antenna when the "CD Player" is used, and to extend the antenna when FM/AM is used. I was expecting pin 7 only to be +12v when the CD changer is selected (coming out of the MX3192).

I am 2000% sure I got the right pins because I checked my wiring 4 times. Then again, perhaps the wiring diagram pinout is not 100% correct. Maybe I should try pin 6 (even though pin 6 is supposed to always be +12v?)

But I have a bigger "problem" --- I feel embarrassed to ask this ---- where is the power conntector plug for the antenna? See here:



??!?!?!?!?! I realized that it does not matter if I have this connector plugged or unplugged, the antenna still goes up and down when the BE1432 is turned on. Am I stupidly looking at the wrong electrical connector??? Note that my car has the mobile phone option that was installed by the dealer.... but clearly there must be some other electrical connector to the antenna because otherwise how would it still be getting power even though I unplugged this 6-pin connector?

 

[Kyiv]

@Jlaa, awesome skill set. Eventually, out of necessity, I plan to acquire one as well. Can't imagine letting some money dive into my dash (for example) to work on electricals.

Perhaps, in the future, you could record your work process with a phone, then fast pace it, then post it here?

 

[speedy300dturbo]

But I have a bigger "problem" --- I feel embarrassed to ask this ---- where is the power conntector plug for the antenna? See here:

Jlaa, that large plug is for your sunroof motor. There should be a smaller square-ish electrical connector on the antenna unit itself.

 

[Jlaa]

Perhaps, in the future, you could record your work process with a phone, then fast pace it, then post it here?

You mean time lapse? Hahahahhahaahah you will have to watch me work, eat, drink, drink some more, scratch an itch, work, burp, eat, etc....

Jlaa, that large plug is for your sunroof motor. There should be a smaller square-ish electrical connector on the antenna unit itself.

Thank you. I knew I was being an idiot. That motor did not look like any of the hirschmanns on @gsxr ‘s w124performance.com site.
Tomorrow I will try and see if DIN pin 6 shows +12v only when the BE1432 has “CD changer” selected, and if it does, I will attack the antenna again.

 

[gerryvz]

 

[Jlaa]

Ok, I will have to give up on “automatic antenna retraction” as conceived because I tested pin 6, and I found it to be +12v regardless if the 1432 is set to radio or CD.

This means the only way to do this is with a manual switch for the antenna. Accordingly, the cleanest way to do this aesthetically speaking would be to use 9-switch dash wood.

Since 9SDW is NLA, I emailed Madera Concepts about cutting holes in 8SDW. I noticed Jeff Wayco is no longer replying.

Anyone know what happened? Same phone, same email .... just no Jeff???

 

[darek_u]

But I realized something unfortunate --- No matter if the Becker 1432 is set to cassette, FM, AM, or CD, the measured voltage between pin 7 and pin 8 (ground) is always +12V! This means I cannot use pin 7 as a signal to automatically retract the antenna when the "CD Player" is used, and to extend the antenna when FM/AM is used. I was expecting pin 7 only to be +12v when the CD changer is selected (coming out of the MX3192).

damn that's a real bummer... On my diagram pin 7 is marked as "+12V control", I just double checked it... On yours it says "ACC" - maybe CD is powered always with key in ACC position??? This isn't very clever unless the power consumption in stby mode is minimal.

 

[Jlaa]

damn that's a real bummer... On my diagram pin 7 is marked as "+12V control", I just double checked it... On yours it says "ACC" - maybe CD is powered always with key in ACC position??? This isn't very clever unless the power consumption in stby mode is minimal.

Yeah, "ACC" / "+12 V control" pin 7 is always +12V as long as the Becker is turned on, regardless of input.
If the Becker is turned off, then pin 7 shows no voltage.

This is all, of course, after the MX3192.

 

[Kyiv]

you will have to watch me work, eat, drink, drink some more, scratch an itch, work, burp, eat, etc....

Scratching your itch and burping, while performing electrical work will only make you more relatable

 

[RicardoD]

This is insanity and at the bottom of list of "problems that do not need to be solved" on our cars. But that is what makes you special Jlaa

 

[mikeym]

I looked into a while ago and there is no simple solution. So just unplugged antenna in the trunk. On occasions I need FM, it seems to work fine around the city except when under the tunnel. Otherwise, don’t miss the antenna

 

[Jlaa]

I looked into a while ago and there is no simple solution. So just unplugged antenna in the trunk. On occasions I need FM, it seems to work fine around the city except when under the tunnel. Otherwise, don’t miss the antenna

That makes sense, but then the antenna doesn’t extend. :-(. That’s not absurdly solving a problem that doesn’t need to be solved. Absurdity is in my repertoire. Rationality is not.

 

[Sam SL]

It's really too bad MB did away with this switch on the 124's. Not sure if early ones had it.

 

[gsxr]

Early 124's did have the ANT switch. Think it went away with the first facelift in 1990, if not earlier.

 

[gerryvz]

That is my observation, as well. The W124s had the switch through the 1989 model year, and it went away in 1990. R107s - went away with the end of production of that model in 1989. W126 - went away with the end of production in 1991.

 

[Ascension]

Early 124's did have the ANT switch. Think it went away with the first facelift in 1990, if not earlier.

My 90 300TE has the switch .

 

[maw1124]

You could buy a modern head unit @Jlaa, and then the antenna would only go up for radio reception (which is never).

Jokes. Nice “old college try” though.

maw