Power Antenna Woes-85 300SD

[regsatx]

It appears my antenna is history. It is getting current from radio (aftermarket Pioneer AM-FM-CD installed by previous owner) but I can't hear motor working. I assume this means motor is gone since it is getting power, and I can't just replace the mast???
Any other suggestions for verification motor is fried??? And if so, best place to obtain compete antenna w/motor, as I don't know you can just replace motor. I'm just a so-so do-it-yourselfer, so help is welcome. Radio works OK, but several stations fuzzy. CD, of course, works fine.
CAN I JUST FORCE UP THIS ANTENNA A BIT UNTIL I REPLACE to improve reception??? If motor gone, would that hurt anything???

85 300SD,
225k Astral Silver

[donbryce]

How do you know the motor is getting power? Did you unplug the antenna and test the lead(s) from the wiring harness? If original Hirschmann, there should be a fused power supply lead, a ground, and 3 leads from the dash switch. The dash switch supplies current as a 'trigger' to vary the position of the antenna (a dumb idea IMO which went with the old Becker radios).
Regardless, the easiest way to verify the motor is to remove the antenna and check the 2 leads directly on the workbench. If the antenna is original, it's probably long overdue for a cleaning and inspection anyway.
Removal is easy. Take out the trunk liner and expose the unit, remove the screws from the lower mounting bracket, unplug conector, and pull down to pop the head out of the rubber grommet in the fender (or unscrew the mounting nut if that's what you have).
On the bench, take a flat blade screwdriver and insert into the catches around the perimeter of the casing, give each a gentle twist to release and gently pry up on each one to get the cover off (easier to do than describe). Inside, you will see 2 wires from the motor (ignore the circuit board). Use a 12V source (spare battery, charger, whatever) and clip + and - to the motor leads. One position will make it turn clockwise, the other counterclockwise. You'll hear it try to move, and if so, reverse the leads and the mast should go up. Nothing, and it's toast.
You can manually get the mast up by putting the antenna back in without the cover (you could, I suppose, get the cover off while in the car too, but it would be awkward undoing the clips), then roll the little wheel with your thumb. Pulling on the mast directly may break the nylon cord teeth or some other internal drive part. And don't cut the cord, as one astute poster once noted, or the mast will free-fall.
The best place for a replacement (original) is EBay. There's a guy in CA that repairs these (Walter Odemer) http://www.geocities.com/odemer@sbcglobal.net/ , and several on-line sources for parts eg. http://www.antennaworld.com/ I very much doubt that the motor is bad though. From your other post, I suspect a wiring problem.

[regsatx]

Thanks for your helpful reply. The antenna went out very suddenly after a fuse blew (#15 which controls interior lights, antenna, etc, which has been replaced). Perhaps antenna caused fuse to blow??
To answer your question, I checked for voltage going to antenna from stereo, so I know power is going from that source. Don't know how to remove dash antenna switch??
• WHERE is fused power lead you mentioned located?
• HOW do I remove the antenna switch on console AND is fused lead behind it?
Tomorrow, I will follow your advise and remove antenna and check thoroughly.
Thanks again for your help!!

[donbryce]

See other post for removal of switch. Your #15 should be the only fuse for the antenna. I'm betting the fuse blew from the antenna motor trying to move the mast cord. This may have fried the circuit board inside the antenna too. If it's real scuddgy inside, or something has broken, a review and damage assessment is in order. You're probably best off if there's damage to the board to look at a replacement. EBay often has good used Hirschmanns. I got one for about $40.00. I'd far rather have a good used original than a replacement any day.
If the boards OK, and the motor works, a thorough cleaning and lube will bring it back good as new. Here's a schematic of the setup, on a W126

[regsatx]

I will get back to you with my findings...and a big thanks to donbryce for the diagram!!
You guys ROCK!!!

[regsatx]

Regarding the two fuses shown, "g" and "h", it appears that "g" is the 15 amp fuse box fuse (is this correct) and that "h" is WHERE??? Can anyone clarify.

Thanks