Hirschmann Not Working? Or is it?

[justinperkins]

A little back story: I have an 87 300TD with no radio and a broken antenna mast. In my opinion the broken antenna is much more unsightly than the missing stereo, so getting the antenna in working order was a higher priority than installing a stereo. I didn't feel like plunking down $40 to have a mast delivered to me, so I grabbed an antenna with a good mast at the junkyard. I figured I might have grabbed a good, working antenna, so I learned how to test the antenna.

This is what I learned, hope this helps somebody.

The antenna connector is 5-pin (it's really a 6-pin connector, but missing the #3 pin). #2 is hot (always hot) and #6 is ground. With just these two wires connected, your antenna wants to retract the mast. This is the antenna's steady state. The Antenna Up/Down switch on the dash sends a 12V signal to the #1 or #5 pin. I've got some faulty wiring at my switch right now so could not test these functions (so I don't know whether power at #1 makes the antenna go up or down).

When you power up your stereo, if the power antenna lead was properly connected, it will send 12 volts to the #4 pin, which makes the antenna go up. As soon as that power source is interrupted, the antenna immediately goes back down again, remember down is the antenna's steady state.

With this simple information I was able to determine that the basic wiring to my antenna was good, but the wiring from my antenna switch on the dash was bad. I am also able to harvest antennas from the junkyard and have the means to test them.

Hope this helps some people fix their antennas. I'm still on the fence as to whether I should have posted this in the Car Audio forum or not, but I like this forum a lot and want to help people out here. I never read the other forums and I'm pretty sure I'm not the only one.

If you want pics, let me know and I'll post 'em.

[nhdoc]

The power antenna, like the ACC system in these cars is over-engineered. That stupid switch is the reason they need 5 pins and a complex controller making the antenna more costly than it needs to be. Hirschmann makes a complete replacement kit which I recently bought to replace the antenna in my 300CD:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&viewitem=&item=280058735312

This one is simpler, has 3 wires...one is a ground, one is +12V constant and one is +12V switched to the stereo's power. It also comes with all of the rubber fender fittings for any MB chassis for a stock look on top. Installing this one with a simple control at the radio meant the rocker switch would not do anything, but since I have never used the rocker switch on the dash anyway it doesn't bother me at all. For $40 I'm not fighting with a 25 year old antenna. The whole unit was cheaper than just a replacement mast for the original and it seems to work fine, so far anyway.

[justinperkins]

Originally Posted by nhdoc

The power antenna, like the ACC system in these cars is over-engineered. That stupid switch is the reason they need 5 pins and a complex controller making the antenna more costly than it needs to be. Hirschmann makes a complete replacement kit which I recently bought to replace the antenna in my 300CD:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&viewitem=&item=280058735312

This one is simpler, has 3 wires...one is a ground, one is +12V constant and one is +12V switched to the stereo's power. It also comes with all of the rubber fender fittings for any MB chassis for a stock look on top. Installing this one with a simple control at the radio meant the rocker switch would not do anything, but since I have never used the rocker switch on the dash anyway it doesn't bother me at all. For $40 I'm not fighting with a 25 year old antenna. The whole unit was cheaper than just a replacement mast for the original and it seems to work fine, so far anyway.

5-pins is only 2-pins more than the one your speaking of, and those extra 2-pins are just for the antenna switch. The failing point of these antennas is hardly ever the motor, it's usually the mast and then secondly maybe the relay board inside the antenna, both of which are replaceable individually.

I'll do a part 2 to this showing the inside.

[justinperkins]

Here's a step-by-step to getting to the core of the Hirschmann, the electric motor.

We want to take this baby apart:


1. With a flat-blade screwdriver, pry the clips open one-by-one. Don't press too hard with your screwdriver otherwise you'll break clip point. Pry like this:


2. Once you go all the way around the motor, the cover should come right off and this is what you'll see (your relay board may differ slightly):


3. Pull the 5-pin connector up and out of the way:


4. Pull the circuit board up, use a flat bladed screwdriver to get it going:


5. Take a photo or right down where the red and green wires (the two wires coming from the motor) connect to the board, if you hook them up wrong when you are putting it back together your antenna will behave in opposite mode. Once you wrote that down or took a pic, disconnect those two wires and put the circuit board with 5-pin connector still attached to the side. Since your circuit board may differ from this one, don't rely on this picture:


6. Unscrew the upper part of the antenna, this is the piece that shows on the outside of the vehicle:


7. Unscrew that phillips screw on the plastic body, this hold the mast stand in place:


8. Now you can unscrew the mast stand and put it to the side:


9. Now you've got just the motor and it's gears, take it to a battery and hook up some leads to a 12V source and see if it operates. It doesn't really matter which way you hook it up, the motor spins both ways. If you have an old mast you need to get out of the antenna, just run the motor until the mast comes all the way out (note the way the teeth are pointed when they come out).


There's a pretty good chance your motor is fine and your circuit board is just fried. You can buy replacement boards easily online. I had a great link the other day from a place that would even give you $25 (I think) for non-working German made Hirschmann antennas, they sold just about every part known to man for this antenna.

I'll update this thread when I dig up the link.

[greasybenz]

maybe i should look into this on my W124 as well. My antenna stopped going up and i was going to replace it with a manual one from Hirschmann like i did on my 300SD.

[Mark DiSilvestro]

Originally Posted by nhdoc

The power antenna, like the ACC system in these cars is over-engineered. That stupid switch is the reason they need 5 pins and a complex controller making the antenna more costly than it needs to be. Hirschmann makes a complete replacement kit which I recently bought to replace the antenna in my 300CD:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&viewitem=&item=280058735312

This one is simpler, has 3 wires...one is a ground, one is +12V constant and one is +12V switched to the stereo's power. It also comes with all of the rubber fender fittings for any MB chassis for a stock look on top. Installing this one with a simple control at the radio meant the rocker switch would not do anything, but since I have never used the rocker switch on the dash anyway it doesn't bother me at all. For $40 I'm not fighting with a 25 year old antenna. The whole unit was cheaper than just a replacement mast for the original and it seems to work fine, so far anyway.

I too bought the same low-budget Hirschmann off eBay. For $40 + shipping, I will mention that this Hirschmann is 'Made in China'. It's for my rusty 240D, which already has a 'Made in Singapore' Blaupunkt radio anyway, so I'm not really concerned with the antenna's country of origin, but thought I would post this for those that might be reluctant to put a Chinese antenna in their German cars. Otherwise, it was about the same price as the common 'Made in China' non-brand power antennas they sell in AutoZone or Pep-Boys, seems to be made well enough, and it came with a huge assortment of fender & body adapters to fit almost any installation, so I'm satisfied.

Happy Motoring, Mark

[Biglex]

Mine doesnt work at all, and it actually looks like the previous owner replaced it with a non-retractable antenna. Bah!

[kafer65]

I have the U6000 model which has is dissimiliar in many ways from the model in the pics. I just put the circuit board back in and wanted to test it out with the help of this thread. The most notable difference is that mine has the #4 as the empty pin not the #3. Number three is the brown ground and #1 is the blue wire. If I give them juice I get movement. It will run until it parks itself when it finds the park section of the little plastic selector gear that trips the breakers on the circuit board. If I switch the polarity it will run in the other direction. My dash switch is uncharted territory and doesn't work. The dome light doesn't either so it may be an wiring issue up front. I can't find any faults with the unit in the trunk. I'm interested in radio reception functionality only and keeping it stock so I'm will be happy to move to more pressing issues after that.

[justinperkins]

Originally Posted by kafer65

I have the U6000 model which has is dissimiliar in many ways from the model in the pics. I just put the circuit board back in and wanted to test it out with the help of this thread. The most notable difference is that mine has the #4 as the empty pin not the #3. Number three is the brown ground and #1 is the blue wire. If I give them juice I get movement. It will run until it parks itself when it finds the park section of the little plastic selector gear that trips the breakers on the circuit board. If I switch the polarity it will run in the other direction. My dash switch is uncharted territory and doesn't work. The dome light doesn't either so it may be an wiring issue up front. I can't find any faults with the unit in the trunk. I'm interested in radio reception functionality only and keeping it stock so I'm will be happy to move to more pressing issues after that.

My dash switch is faulty as well, but the antenna operates fine with the stereo which is what really matters.

From tearing apart two of these antennas, I can see that these circuit boards differ even when the rest of the antenna does not. For example the circuit board that was in my wagon when I bought it did not have the two additional wires connected to the circuit board which are given juice by the switch on the dash. There was just no place to connect them, it was weird!

Then I pull the antenna from an 87 300E and it has a circuit board with connection points for all 5 wires! Well I swapped that circuit board out with the one in my wagon, but my switch still doesn't do anything so I'm leaning towards a bad switch now.

[babymog]

I replaced mine with a Hirschmann DRP-11 3-wire. I used three wires, the ground, hot, and hot with dash switch in center or left (auto or up) position. This allows me to have the radio on with the antenna down if necessary (car wash etc.), works great, always retracts with car or radio off.

[justinperkins]

Originally Posted by babymog

I replaced mine with a Hirschmann DRP-11 3-wire. I used three wires, the ground, hot, and hot with dash switch in center or left (auto or up) position. This allows me to have the radio on with the antenna down if necessary (car wash etc.), works great, always retracts with car or radio off.

Do you have the ability to stop the antenna at any position or is it just up or down with the switch?

I know that with factory antenna you should be able to fine tune the antenna height with the switch.

[Diesel2theMoon]

Removed the antenna because it would not fully retract or fully extend. The cover plate was screwed to the body of the case - not pressed on as the one in this picture. The circuit board, rotator gear, and spring look like one show on Diesel Giant's websight in his tutorial on how to replace an antenna mast.

Why do I post on this thread? After my work on the antenna the motor will not 'shut off' when I turn off the radio. I just grinds away. I finally just pulled the power plug on the antenna and pulled the mast up as far as I could (about 14").

I must've damaged the little gear/lever/spring combo that 'turns off' the motor.

Anybody rebuild a Hirschmann antenna from the mid 80's? Where does on get parts (like the little plastic gear)?

[Palangi]

Performance Products shows a few antenna parts in the 126 section of their catalog.