Jim Chambers

The quest continues, but I'm halfway home. The hard part is done. I have a 6 channel amp and a CD2 which function beautifully in the CD mode. You haven't lived until you've listened to the Best of the Bee Gees through 10 speakers in a 928 (OK, so the Bee Gees are pre-period correct)!
Now for the rest of the story. The radio scans and finds no stations, only static. It behaves as if there is no antenna. I have it plugged into the head unit. I can trace the cable along the passenger side of the console under the carpet. The wiring diagram doesn't help me. Where does the cable go and is there another component between the radio and the antenna.
What worries me is that earlier I took out an antenna wire for an old mobile phone. I cut it at the passenger rear seat where it disappeared under the trim panel. As usual, all suggestions, hints and guesses appreciated.

M. Requin

The original had an inline RF amp. which has probably been disconnected. Look for a small wire attached to the antenna cable (from the antenna) - on my 86.5 the wire that attaches to it is white. Hope this helps, and I'm sure the more experienced will chime in.

Jim Chambers

Thanks Martin. That is a good start. I just talked with Stefan at SW stereo and he spoke of a white wire as well. He was driving in NYC traffic and asked that I call him back later. I have a white wire coming from the multi-pin connector at the rear of the radio and also a second one which is a loop. Does the white wire follow the antenna cable? My antenna is on the roof, not the rear quarter.
Keep those suggestions coming.

Rick Carter

I have a similar problem although I do get some FM reception it is not good and AM is almost non-existent. I have an aftermarket roof antenna. Is Porsche OEM any better? It costs more at about 100 bucks. Also does the the cable make much difference, R-11 for example?

jmrjames

Could the "period tunes" problem be with a time space continuum issue in attempting to dial up radio stations that no longer exist ?

Sorry could not resist

Jim Chambers

I think I need the white dog that sits by the gramophone.

michaelathome

There is a white wire (power) that is attached to the roof ant. Follow that from the back up to the head unit and make sure that it is plugged in/connected.

Michael

StratfordShark

The RF amp is in base of roof antenna. They often go bad after time and reception is then worse than having no amp at all. Try another (unamplified) antenna plugged into radio first to check that the head unit receiver is OK.

Had to replace my roof antenna as it wasn't receiving anything. I found a Golf (Rabbit?) Mk II antenna which was a close replacement but I had to modify the power connector to leave the power lead entering at side of sunroof aperture as original, and needed adapter to link to the coax cable of car. Reception is great now.

RET

The roof antenna has an amplifier built into its base and the symptom of its failure, or lack of power, is poor FM reception and no or almost no, AM.

You should be able to check for power close to the base of the antenna: the coax signal cable and the amplifier power wire both had connectors a few inches inside the roof opening and should be easy to access ( at least they were in my sun roofed '89, anyway...). The antenna's amplifier should have power whenever the head unit is on.

Replacing the antenna is pretty simple, but I recall some problem with new versus old style antenna connector types: make sure that you get the correct one to match your installation.

Marine Blue

Hmmm I don't remember the Bee Gees being all that popular in the 90's.

I do agree, the stock stereo does sound pretty good when everything is functioning properly. Now I just need to find yet another CD2.

Jim Chambers

I have everything right at the head unit with the white wire powered. Haven't yet checked that the power is making it to the antenna.
It appears that the antenna is above the sunroof motor. Does it have to be removed to replace the antenna with its booster?

I'm also getting great sound from the 4 door speakers. The rear 6 are quite muted. Stefan at SW stereo tested the amp and all 6 channels were good.
I wonder if the PO did some rewiring there. He pretty much screwed up everything else when he installed an aftermarket system and then did a half-assed job of trying to return to OE. Used the wrong amp and messed up the wiring to the head unit. I am 90% there, but the last 10% is a bear.

Afshin, I admitted in my post that they were "pre-period correct".

jmrjames

I am in the process of replacing the head unit in my 1991. I believe that this is the forth change and there is quite a mess. The antenna cable has a black wire taped to it which was not connected to anything. I have not unraveled the tape to see if this black wire is connected to a white wire.

Should I check to see if there is a white wire ?

If I find a white wire should I connect it to a power source ?

Is the turn on amp power line a proper place to connect the white wire to power the antenna amp and the speaker turn on amp ?

Thank you for your advice.

SQLGuy

Any idea how the PO was driving the rear speakers? If he was using two channels of a four channel amp to drive all six rear speakers, then the cargo speaker is probably in parallel with the B-pillar speakers. One thing to check would be to set the head unit fade and balance to go to RR, and disconnect the amp's connection to either the RR B-pillar or cargo speaker. If you're still getting sound from both the cargo and B-pillar speaker at that point, you'll need to find out where they're connected together and fix that before using the system again.

Cheers,
Paul

Jim Chambers

Thanks Paul. You may have the answer. I will follow your advice and report back.

jmrjames, my '90 should be the same as your '91. The factory connector to the head has a brown ground, red power, both with larger spade connectors. Then there is a smaller gauge red which is the amp power line. All three are contained in the same harness. Also there is a green/brown stripe wire which relates to the theft deterrent system (mine is not connected).There is a small white "loop" which comes from and returns to the connector and a second white wire exiting the connector. It then connects by a male/female connector to the black lead that follows the antenna. It is hot and powers the antenna booster when the radio is on. Assuming your factory connector is long gone, you will need to connect the white/black to power up when the unit is turned on. Hope that helps. If not, let me know. I am reporting from memory and I can take another look at the wiring diagram if necessary.

StratfordShark

From memory I think you only have to unbolt and remove the reducer gear and slide it out of rubber connector to expose the antenna base, and you can leave the sunrrof motor in place.. I think you have to undo one or two of the rubber buffer mounts to be able to flex the sunroof drive cables clear of the aperture for the antenna, but again this is simple and will be obvious when you have the sunroof cover off.

With the cover off and before removing the antenna, you can just unplug the 12V connector powering the base amplifier and see if you have 12V when head unit on.

Photo shows the view up towards antenna base. On right side you can see the amplifier power lead and its connector, and just below that is the antenna coax cable.

Also shown is the original antenna amplifier. I think the potting compound used to encase the amp components has decayed into a foam-like substance. At any rate the amp wasn't working and it had power.