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Radio noise suppression capacitor


hukre's Avatar
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11-12-03, 10:25 AM   #1  
Radio noise suppression capacitor

1968 Mustang.
The wire on the small capacitor mounted at the voltage regulator has broken off. The Ford dealer quoted me $ 56 for a replacement. Can I use a capacitor which is used on the old points type distributors instead? they are about $ 4.

 
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carguyinva's Avatar
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11-12-03, 10:46 AM   #2  
possibly...

...if the old one has any markings on it, they may be helpful. the most important piece of info would be the rating in volts and microfarads...so for example it may have printed on it...50mf, 250volts...then you could go to radio shack and match something up...the other thing is possibly a shop with an old scope could measure the capacitance of it. some DVOM's have a capacitance feature on them...know anyone in the electronics field?

 
trinitro's Avatar
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11-12-03, 11:16 AM   #3  
What kind of capacitor is it? It's bound to have markings on it, and it is probably a film capacitor. What does it look like (radial, axial, tubular, etc).

 
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11-12-03, 03:27 PM   #4  
A car audio place would likely be able to help just by looking at it and cheaper than Ford.BTW what Ford dealer would still have one of those?

 
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11-12-03, 06:53 PM   #5  
To all of you who showed interest and posted replies, thank you.
The capacitor is a little round can type, 1-7/8" long and 5/8" diameter. The part number stamped on it is: Autolite C60A-188832-4, no mention of voltage or capacitance. I was wondering if it was still necessary to have since the voltage regulator is now an electronic type and there are no noisy contacts chattering as was in the original unit. Drove around today without the capacitor and couldn't hear any more noise than usual.

 
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11-13-03, 03:31 PM   #6  
Hukre,

I was just wondering what you meant when you said,

Originally posted by hukre
...since the voltage regulator is now an electronic type ...
Did you replace the OEM fender mounted Ford box shaped regulator with some new fangled device? The reason I asked is because, as far as I know, the OE parts are still sold. Perhaps you found a way to install a new alternator with a built in regulator and its own capacitor. If this is so, I would be interested to hear what modifications you made for the sake of learning.

The alternator capacitor suppresses the noise caused by the brushes inside the alternator, instead of, as you say, "...noisy contacts chattering...' inside the regulator. If you don't hear alternator whine thru your radio, then perhaps the problem is solved before it began. Also, perhaps you replaced your radio with a newer more expensive radio which are better at noise suppression. Still, I would sleep better with a new capacitor, all things considered. For example, you may get the whine on a out-of-town trip with a weak radio station signal, or under heavy alternator loads, or as the brushes wear down with age.

In my experience, Ford capacitors and resistors are seldom stamped with useful values. Thus instead of buying a $3 capacitor, Ford is happy to sell you a $50 regulator. The same thing happens on heater blower resistor stacks. Because we don't know the resistor rating of the 5 cent resistor, we have to buy a $25 stack.

Find an HVAC professional and they will have a DVOM that can determine the capacitance of your unit in a heartbeat, just as carguy mentioned. Capacitance DVOM's are standard tools for the HVAC guy.

Then use that capacitance number to find a good parts guy that will look up your capacitor in a Borg Warner Ignition (or electronics, whatever) catalog. I know because I recently did just this to replace a radio capacitor on a mini van. But you need a guy that knows his way around a Borg Warner catalog. If you get the capacitance number, but don't find a good parts man, I would even try to get the correct Borg Warner part number for you, so you could order it at any auto supply. Mine was around $3.

 
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11-14-03, 02:44 PM   #7  
Thanks Lugnut for your helpful comments. It makes sense that the alternator brushes cause radio noise rather than the regulator contacts as somebody told me. As for the regulator, I replaced it with a Motorcraft from the Ford dealer. It is an electronic type and I was told that it replaces the original relay type. It was $ 45.53, the little capacitor was an extra $ 56 and I didn't buy that. The new type regulator has the same footprint as the old one and mounts in the same place. It is however lower since there are no relays inside. As for my old capacitor, unfortunately the wire broke off right at the capacitor and I can see a couple of strands in the little hole where the wire came out of. I will try to shave off some of the area around there and see if I can get a hold of the strands for measurement. The radio has been replaced years ago with a modern solid state type and it has a lot better sound than the original.

 
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