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Using the stickys on this forum, ive been troubleshooting my Bose sound system in my 93 touring. I am basically restoring a car that has sat up for probably 2 decades. I have the car running and driving but the stock head unit was completely lifeless. I caught a good deal on Crutchfield for a head unit, line converter and install harness and installed according to thier instructions and information found here. Currently I have no sound at all from any speakers, no static or anything. I ensured the "radio relay" is being powered up, the remote wire is hooked up and sending power to the B/R wire that is supposed to power the amps. I checked with a volt meter and had 12v at the plug between B/R wire and the B/O ground wire, also verified to chassis ground. I just cant see all the amps being bad to the point where nothing works at all, the car was mostly stored indoors and stock with very little signs of modifications. Once again, stereo powers up and shows song being played but no sound and remote wire is connected, relay verified turns on. If anyone has any advise I would greatly appreciate it as Im a bit stuck unless I just replace everything which I do not care to do. Thanks in advance
I think it's possible that all the amps go bad, but still you would most likely get some noise out of speakers. What I would do is test the speaker wires by a spare speaker (just any automotive speaker, can be the cheapest speaker from amazon) and a pair of jumper cables with spade connectors. This test will narrow down possible causes. Something like this (in this pic it was connected to green and blue wires):
So I have since tried to wire in a speaker into all the channels and got nothing from any of them. From the head unit itself I can get sound, so I know its either the line converter or all the speakers/amps. I thought that I would be able to get static or something but still get nothing past the converter. I talked to Crutchfield, and the guy I talked to was actually very knowledgeable. He agrees that all the speakers and amps are unlikely to be bad, of course he asked if I had hooked up the remote wire and knew about the light green/black wire. All that was fine of course, we concluded that the line converter is a likely suspect and they are sending me a replacement. Ill update what I find.
Well unfortunately the new line converter didnt work either. currently I'm using the body manual troubleshooting section to trace the connectors out through the body but I suspect that I need to buy some amp/speakers to test wiring in the car. I wish I knew what readings to expect at the speakers, the crutchfield support guy stated it would be a pulsing low AC signal but I was not able to see this with my Fluke meter, I have an old Simpson that I might try. Any audio experts know what the signal should look like? I can go back to the input to the line converter where I know its good and work from there.
Have you tried connecting a door speaker directly to the headunit? Also I'd check the continuity between the plug to the door amp and the plug to the headunit adapter.
I have tested the head unit with a traditional speaker and it works on all channels. I will look into the testing the speakers with a battery. I didnt want to remove the door panel yet as not to break anything, I realize this might have to happen at some point anyway but I was looking to at least get some sort of sound. I would like to check the signals going to the amps themselves that way I can check the line converter and work my way back to the individual components. I still find it improbable that all the speakers and amps are bad. Currently I am doing some paint correction and took some time to ponder on the audio stuff.
OK, so Ive done some more troubleshooting and research. I used an old Simpson meter which is quite sensitive to compare input signals to the output signals in the CRUX LOC1 that I suspect is the problem. What I found was pulsing AC signals that would modulate with the volume **** on the input side of the line converter, this a known working signal tested with a speaker. I then tested the output side of the converter expecting a lower magnitude but pulsing signal indicating that it was actually passing signals. I still have nothing at all out of this line converter, I had the Simpson meter set at 2.5 volt scale and not even a bump on the needle. The Scosche converters in the old posts seem to be unavailable now so I will dig around to see what I can find. I am determined to get this system working, wish me luck.
This is what Crutchfield stated was appropriate for the car. I have since found and ordered a scosche OEA4 which is supposed to be here today. BTW the tech guy I talked to at Crutchfield has been very helpful and willing, even offering refunds for whatever I have purchased to get the system working.
you cut the RCA plugs off and there are the 2 wires just as the Scosche converter would have. The Scosche OEA4 line converter didn't work either, I'm going to take some measurements at the output of the converter tonight and see what I have. Going to verify 12v at the amps again as well. I plugged in the factory head unit to see what happens as well, it just has backlight. I turned the volume up on it and still getting nothing. I guess I am going to drop back to the wiring diagrams again and start double checking everything.
Well I have installed the scosche line converter and have pulsing AC signals coming from it with a magnitude of about .5vdc to about 2vdc depending on the volume and how high I have the potentiometers set. I briefly had the door speaker playing and the rear bose unit is working but is very quiet. My plan now is to check the signal at each speaker to see if its the same. I definitely expect more volume from the bose, its barely audible.
So I have pulled the door panel and I am getting voltage to the amp and expected signal for the speakers now but still no output. I suspect that the amps are all bad at this point, the rears are playing something but barely audible. Guess Ill get on ebay and try to source new ones or see if the currently installed ones have obvious issues that I can repair.
So I have pulled the door panel and I am getting voltage to the amp and expected signal for the speakers now but still no output. I suspect that the amps are all bad at this point, the rears are playing something but barely audible. Guess Ill get on ebay and try to source new ones or see if the currently installed ones have obvious issues that I can repair.
I ordered new amps directly from Bose automotive through a phone call several years ago (I think 7 or 8). It might be worth giving them a call, maybe they still have new amps in their stock. https://www.bose.hk/en_hk/automotive...t_us_form.html
So I rebuilt all the amps in the car and was very happy how it turned out, it sounds very good for the cost. Hell the speakers are original to my knowledge. I'm still shocked that all of the amps were bad but here we are, anyhow everything is working now.
I used this thread below for parts and knowlege https://www.rx7club.com/3rd-generati...-amps-1150545/
I replaced the caps and mosfets on door and rear amps, I am having issues with the center amp but sounds great without it. There was some board damage on some traces and corrosion that I'm not sure I can work around.
05-30-24, 08:03 AM
All bose amps bad?
