TD Hirschmann antenna help - PeachParts Mercedes-Benz Forum

Stevo · #1 04-16-2010, 01:28 PM

My antenna does not go up when the radio comes on. Is it possible to get the antenna up and have it stay up, so I can at least have some tunes while I attend to the other more pressing issues on my, new to me, euro TD. Perhaps put 12v to the red wire of the motor, I have not had the opportunity to mess with one of these antennas. I've looked at the instructions for mast replacement but dont see anything about checking for 12v to the motor or "getting it up and leaving it up" Maybe a replacement for the Hirschmann that I can stick in for now?

okyoureabeast · #2 04-16-2010, 01:48 PM

Go ahead and pull the cover off and take a look at the motor.

In my case there is a tiny daughter board that rests on top of the unit that changes the polarity to get the little DC motor to spin.

If you pull the unit out you might as well try and see what is wrong since it is so easy to fix. Apply 12 volts to the motor and see if it moves. If it does I can almost guarantee the little board on top is fried. Simply replace it!

Oh and make sure that the motor's little cable on top is connected properly and is supplying a current.

nhdoc · #3 04-16-2010, 01:55 PM

You can just grab the nub with a pliers and pull the mast up if you are planning on replacing it anyway. There is a mechanism which will allow the nylon tail to slip (which is what it does when the antenna goes all the way down and the motor keeps on running for a second or two). You won't do any damage by just pulling it up manually and if the motor isn't working it will stay up until you fix it.

my83300cd · #4 04-16-2010, 04:11 PM

Pssst- did you check the antenna rocker switch to make sure it is in the right position? Occasionally someone messes with mine and the first thing I think is that the antenna is effed up.

Stevo · #5 04-16-2010, 04:29 PM

Quote:

Originally Posted by nhdoc

You can just grab the nub with a pliers and pull the mast up if you are planning on replacing it anyway. There is a mechanism which will allow the nylon tail to slip (which is what it does when the antenna goes all the way down and the motor keeps on running for a second or two). You won't do any damage by just pulling it up manually and if the motor isn't working it will stay up until you fix it.

Thanks, I'll just grab hold of the "nub" and pull it up then, I was worried about breaking if but if thats not a problem I will be able to fix it proper when i have a chance.

Stevo · #6 04-16-2010, 04:31 PM

Quote:

Originally Posted by my83300cd

Pssst- did you check the antenna rocker switch to make sure it is in the right position? Occasionally someone messes with mine and the first thing I think is that the antenna is effed up.

I dont have a rocker for the antenna, actually my 85 240D doesn't have one either, both cars are Euros, maybe thats the deal.

Stevo · #7 04-16-2010, 04:34 PM

Quote:

Originally Posted by okyoureabeast

Go ahead and pull the cover off and take a look at the motor.

In my case there is a tiny daughter board that rests on top of the unit that changes the polarity to get the little DC motor to spin.

If you pull the unit out you might as well try and see what is wrong since it is so easy to fix. Apply 12 volts to the motor and see if it moves. If it does I can almost guarantee the little board on top is fried. Simply replace it!

Oh and make sure that the motor's little cable on top is connected properly and is supplying a current.

Thanks, I'll save your post and hopefully get to a full repair soon, next on my list is the locking system, but I need tunes in the meantime

vstech · #8 04-16-2010, 11:07 PM

My euro 240D 5 speed has the rocker, so it's not a euro thing...
I pulled out the antenna (it takes like 10 seconds) two small bolts, and the nut on the antenna seal going through the fender.
opened it up, and cleaned all the gunk out of the thing. rigged the motor to a battery, and played with it. turns out the sections were corroded, and siezed. sprayed a little chain oil on it, moved it a bunch, and VOILA! full function on the old thing.
I bet there are a LOT of antennas that need lube after all this time. amazing they work this long! I have a lot of cars, so I started looking at others, and found a lot of them were corroded so badly, the masts have to be replaced. some maintenance in that area could have saved them. get some oil on your mast and move it up and down and it will be standing full height in no time!
ok, re reading that it sounds kinda kinky... eeewwww.

vstech · #9 04-16-2010, 11:09 PM

I also noticed several of my cars have amplifiers on the antenna. is that a rare thing?

Stevo · #10 04-17-2010, 12:26 AM

LOL, sometimes you just have to say it like it is:

The antenna on my 85 240D euro has worked flawlessly with only a little "silicon on a rag" swap down occasionally so I've never fooled with one, new territory, I guess. I too have a few parts cars so I may "experiment with one of those first, then maybe I'll have a "stand by" antenna.

An "amplifier" humm, I have this strange looking device bolted to the roof of my glove box that I haven't ID'd yet, I don't suppose thats an amp

good luck with your cam problem. I had to replace a cam on my daughters 78 240D and there is a difference in the "early' and 'late' cams but I dont recall the details.

nhdoc · #11 04-17-2010, 07:53 AM

The box mounted above the kick panel is an amp for the radio. The factory radio is a two-part affair. The head unit has no power amp in it and the low-level output is fed via a DIN plug to the power amp. In that amp is the antenna switch too IIRC - in other words, the antenna motor is fed its signal from the power feed from the amp.

Stevo · #12 04-17-2010, 10:37 AM

Quote:

Originally Posted by nhdoc

The box mounted above the kick panel is an amp for the radio. The factory radio is a two-part affair. The head unit has no power amp in it and the low-level output is fed via a DIN plug to the power amp. In that amp is the antenna switch too IIRC - in other words, the antenna motor is fed its signal from the power feed from the amp.

The little black box bolted to the overhead of my glove box (5 spd, Euro, 85, TD) was professionally installed, by the looks of the work and has a tag "Zum Radio, for use with electronic radios only". It has 13 push buttons, must be for some sort of antiquated "satellite radio

The radio in the car now is a mid/low quality radio/CD unit.

Stevo · #13 04-17-2010, 02:19 PM

Up date, 12v to the motor but the motor does nothing so I 'cranked it up "26" by pulling up and turning the little "flat belt". there was another female antenna connector down with the other wiring which most likely goes to that gizmo in the glove box so with the antenna up and plugged into the radio/CD player all is well. Thanks for the help, there is no corrosion inside the unit so when I get a chance I'll try and fix it or snag one from my parts cars.