Doug Chase

Hi everybody,

I'm working on a friend's RX-7 ('91 convertible) so I've been looking through the forum a lot the past few days and you've already helped me a lot. I've done quite a few searches and I've found the solution to all of the idiot lights staying on and I've found out how to repair the wiper switch instead of paying $395 (!!!) for a new one. Thanks. I would like to personally thank Icemark and HAILERS. In the searches I've done you've helped me out a lot.

I'm on enough other forums and mailing lists to realize that it's in somewhat poor taste to make your first post a question, but unfortunately I need to do that.

This problem is concerning the radio. It's the factory stereo with the CD and tape player and it has the headrest speakers. Again, this is a '91 convertible with airbag. My friend mentioned that the right headrest speakers quit working a while ago so since I was waiting on the relay for the wiper switch I decided to dive into this.

This will be sort of a roundabout description of the problem, but I think the details may be important so I'm putting everything in here.

I turned the ignition switch to ACC and the radio doesn't work. No sound, no lights, the antenna doesn't come up, nothing. I pressed and held the AM / FM / CD / Tape buttons and still nothing. I pressed the power and surround buttons for the headrest speakers and again, nothing. The power and surround buttons didn't light up and there was no sound.

I pulled out the radio (thanks to you guys I figured out how to remove the radio surround without breaking anything) to check the wiring and plugs. Everything looked ok so I plugged it back in and set it in place (not screwed in though). Since the only changes I've made to the car were to remove the dash cluster I decided to undo that. I plugged the headlight switch and wiper switch back in. Hey, now when I turn on the lights then the radio buttons light up, this is progress! Still no signs of life from the radio, though, but now when I press the power and surround buttons for the headrest speakers they light up, and I hear small noises come out of the subwoofers when I turn ACC off.

Then I wondered if the radio grounded through the chassis instead of a ground wire so I screwed the radio in place. The radio is still dead and now the power light for the headrest speakers won't light up. It will still light up when the radio is not grounded. The lights on the buttons still come on when the headlights are on.

My question to you all is this. Did I damage the head unit and / or amplifier and / or headrest amplifier when I either a) tried to operate the stereo without the headlight switch plugged in, or b) tried to operate the stereo without it grounded?

I already searched on this problem and found some good information, including wiring diagrams, here: https://www.rx7club.com/forum/showth...threadid=73555 and here: https://www.rx7club.com/forum/showth...threadid=72202 but I haven't been able to find the answer to this specific question.

To answer some more questions before you ask, the fuses are all good and I have 12V on pin C all the time, pin A and D when ACC is on, and pin E when the dash lights are turned on.

Thanks in advance for the help. I apologize again for my first post being a question and for this being so long.

Doug Chase

Icemark

Glad you did you homework doug and that we could help you. Welcome to the board.

As far as the stock radio, yes it must be grounded by being screwed in, or an aftermarket ground wire installed.

However the headlight switch and wiper switch would have no affect on operation, other than the headlight switch does provide lumintation input into the stock radio.

From your description and testing I would say that the radio is history.

You have a couple of options then at that point.

You can replace the radio with an aftermarket one or

Repair the radio. At best repairing can be expensive, but most independent (read non-best buy/circus city/good guys/big chain store that sells refrigerators) stereo shops can either repair or know who to send it too to repair it. However it is not uncommon to spend $150+ to repair a radio, more if there is a CD involved.

If you replace the radio make sure you keep the old factory mounting can and use it to help mount the new radio.

Doug Chase

Thanks Icemark.

Have you dived into the internal radio wiring enough to be able to say if operating the radio with no ground attached would force it to ground through something else (amplifier? headrest amplifier?) and possibly damage something?

If you haven't, do you have any idea where I could dig up internal schematics of this radio so I can try to figure that out?

Thanks a lot. Great board you all have here.

Doug

goblues24

doug i wish you were closer cuz in the next few months im going to overhaul my stereo and i wouldve traded you my working vert radio for your non working one. im going to keep the face of mine and fabricate a sliding hinge to use it as a cover for my aftermarket so it looks stock when not in use. if you plan on coming to sfla let me know. im not 100% on my project i havent taken mine apart to see the numbers on how the face will fit over my soon to be bought aftermarket setup.

sorry i have no feedback for you on your problem but it sounds like icemark is right on with your radio being dead...you ever see it work?

Icemark

The ground will actually run through the antenna and any amps plugged in if the radio was not screwed in.

In therory, the ground should be just too weak, too complete the circuit and should not damage anything.

As far as the schematics, I don't know of any online, but either the local Panasonic, Clairion, or Pioneer service center should have them or access to them (depending on which company manufactured the radio).

On the S5 radios, there were a considerably higher amount of cold solder joints in the radios than the S4 versions. You may wish to just pop your radio open and resolder any plugs and switches inside.