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2006 DTS 1990 Brougham
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43 Posts
Discussion Starter #1
I really would like to keep the original radio in my 90 brougham. However it has a problem that is as annoying as hell. First there is a whine that you can distinctly hear that gets higher in pitch when you accelerate the car. Also when the car is warm or on a warm day the radio has constant ticking/thumping sound coming from it. I would think something new might solve these problems, but it's possible not too. I see used units on eBay which I wouldn't object to, but at $200+ for a used unit that possibly might have the same problems as the other units seems a little spendy. Any advice or ideas appreciated.
 

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1980 FBC
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979 Posts
A whining sound might be a problem with your alternator.

One shorted rectifier diode will allow the alternator to still make rated output voltage but the available current will be low. It will also have ripple which shows up as whining on radios.

The alternator output should be checked by someone with modern equipment or real experience.

I'd go over the car's wiring where there are ground lug connections to make sure there isn't a loose connection also. That could make a thumping sound in a radio.

There are outfits who specialize in old car radio repair. Maybe give one a jingle.
 

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1926 Model T street rod, 2000 Jaguar XJ8, 1999 Corvette.
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6,737 Posts
Simply disconnect the alternator, start the car and if the whine is gone you need alternator repair and/ or replacement. What you describe is rarely a radio fault.
 

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1991 Cadillac Brougham D'Elegance 5.7 Litre, 1994 DeVille
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6,796 Posts
I've had the same problem being loose connection to the alternator. My replacement alternator is very picky for it.
 

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1991 Cadillac Brougham D'Elegance 5.7 Litre, 1994 DeVille
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6,796 Posts
Meaning if the plugs or connectors have become loose at all or the slightest trace of dirt or corrosion there's a good chance of getting the radio interference. The old one never had the problem.
I'm guessing it might actually have something to do with the radio because I've seen the same situation over years that someone replaced the alternator and it started problems even tho the replacement alternator tested OK and had no problems if installed on another car. Or more recently a car that had a new stereo installed, the old one didn't have the interference but the new one does, yet it works great if installed in another car.
 

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1926 Model T street rod, 2000 Jaguar XJ8, 1999 Corvette.
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6,737 Posts
Alternators have radio noise suppressors within them. Some are faulty even on rebuilds and will NOT affect alternator charging operation but cause a whining noise in some radios. Some cars have better grounding systems than others, so its rarely an issue.
 

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1980 FBC
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979 Posts
A new radio install whining is probably a ground loop. The best ones are when the ground only comes from the antenna coax shield.
 

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1985 Fleetwood 75
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345 Posts
The speaker pops are probably the electrolytic capacitors under the heat sink PA circuit board have gone dry, and cracked. pull radio and open it up remove the heat sink on side and re solder in new capacitors probably the
1uf caps just under the heat sink the heat causes them to pop. just replace all electrolytic caps and the problem goes away. note the polarity mark on side lead with - symbol keep them the same as old one when
removed.
try get the 105C rated temp specs if you can for better life. voltage 16V or higher
 

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2006 DTS 1990 Brougham
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43 Posts
Discussion Starter #10
Well. I put in a new alternator. After initially thinking the problem solved I noticed the distinct whining noise return after driving for 15 minutes. Whining pitch increased when the accelerator is pushed and when let off the accelerator the whining pitch decreases. I checked all grounds throughout the car and all were good and tight. I guess the next job is to pull the radio head and perhaps install new capacitors. More work than I was hoping for just to keep a car stock.
 
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