thomo

The Delco-Bose radio on my 89 vette makes a high pitched whine of constant volume. It doesn't change pitch noticibly with engine speed. If you turn the volume up the noise remains a constant volume and is eventually less than the signal level if you crank the volume right up. Does anyone have any ideas as to the cause?

I've noticed the antenna motor seems to have a loose braided strap hanging down from the top of it - where's it supposed to go? There is a copper earthing strap joined to the motor that presumedly goes back to a main earth up front.

Technical support is hard to find in Australia on these cars!

hokiess

Amazing! Mine is an 89 too and does the exact same thing. I'm ripping this whole system out and replacing just as soon as I'm able to wrangle up the extra cash.

jfb

The braid should be connected to the nearest ground.
Each speaker has its own amplifier and there are several electrolytic capacitors on the circuit board that dry out with age which reduces their capacitance. You can replace these electrolytic capacitors yourself if you want to tackle this job. It would only be hard for someone that has no experience repairing circuit boards.

1bdvet

I Also Had The Same Problem Noise, But When I Replaced My Alt. With A Chrome One All Noise Went Away.

corvette1989bham

I am having the same problem on my 89..but it has four new Bose amps.

thomo1

I will try earthing the braided cable on the aerial and putting a 100MF cap on the alternator. It is interesting that someone is having the same problem even with new speaker amps and yet someone else was able to solve it with a new chrome alternator. Replacing the electolytics will be my last resort. (by the way thomo1 and thomo are one in the same - just different e-mail addresses 'cause I couldn't remember my password)

corvette1989bham

Well worst come to worst, I have signed up for Gorgon Killewbrews school (my third time) and we will sovle the problem then. I cant speak highly enough about Gordon and his school...they are the BEST people and know sooooooooooooooo much, I could listen to him talk for weeks! After my last trip I sent them a Thank You basket for the experience.

jfb

Turn the radio on with the engine off. If you don't have the whine, the alternator is suspect, but if the whine is still there, your amplifier's electrolytic capacitors are at the end of their life and need replacing.

corvette1989bham

I have the noise but ALL FOUR amps have been rebuilt, noise if the same from ALL amps. Any thoughts on how to test alternator? Disconnect it with the car running?

jfb

Either turn the radio on with the engine off, or unplug the connector on the alternator when the engine is running to see if you still have the whine. If no whine, the alternator is suspect and absolute proof can be had by using an oscilloscope across the battery with the engine running to see if the alternator is putting out higher than normal ripple. Sometimes the voltage regulator in the alternator oscillates. Also, most modern ignition analyzers allow you to look at the voltage waveform across the battery. Find a repair shop with an analyzer that can look at the battery waveform (engine running) if you cannot get access to an oscilloscope.

corvette1989bham

FOUND IT. It was a corroded NEGATIVE battery terminal bolt. It looked fair but Gordon Killebrew suggested replacing the bolt....instant noise fix.

johns89

I am a new member and found this group searching for a solution to my problem.

I also have an 89 corvette with the same problem. In addition to the whine there is ignition noise. All is fine when the car is not running.

I do not understand what part was replaced. I looked at and cleaned the bolt that connects the negative wire to the battery. It did not change anything. I really do not understand how this could fix the problem. What am I missing? Is there any factory installed noise supression that could have failed?

Any help would be apreciated.

corvette1989bham

I need more details, is your car stock, when did the noise start, have you had amps rebuilt replaced? Are you using OE Bose cassette? I spent months tracking mine down , I had cleaned my negative terminal too but REPLACING the negative bolt FIXED my whine.

johns89

The car is stock and is the original Bose system. No repairs were made. The problem happened all at once. It did not get worse over time. The noise is the same in all 4 amps/speakers.

Any Ideas?

corvette1989bham

Well, replace the neg bolt. Wont cost a dollar and good place to start. Next with car running unplug the alternator completely, did this fix the noise? run a ground wire from the distributor to the solid chassis ground, take the radio out, put in a ground strap from the radios metal case to good known ground (after plugging back up alternator) this is a good starting point ..let me know.

johns89

Thanks for the ideas. I guess I have some work to do.

johns89

I spent some time trying most of these ideas. I then discovered that the noise is present with the ignition On without the engine running, but goes away when switching to the Accessory position. I also noticed that the noise is a little different from each of the speakers. I think that I need to change the capacitors in the amps. Does anyone know what values these are and what is the easiest way to remove them from the doors? I removed the drivers side door panel and it still was not obvious how to remove the amps.

jeo60005

You guys have helped me before, my alternator is making a high pitch whine all the time, had it checked every thing checks out fine. My vette is a 67 327-350hp has a new voltage regulator. Any help would be appreciated, thanks Jack

cliffg

My boss speakers make noise on the right side, door only. When I put the power in the radio makes a pop and then the right door speaker makes noise. You can hear the music but sounds terrible. The rear speakers work but the drivers doesn't. The drivers speaker comes on and off. When it's on the radio sounds great even the right side but it doesn't last. The drivers goes off and the right side starts with the noise again. Any idea what the problem is?

Cruisinfanatic

does moving the ***** and sliders make any difference? If not could be a bad amp in speaker box