Putting my restored dash back in today (67 Big block) and I am a little confused (normal) as to these dash capacitors. What exactly do they do, are they necessary? Which goes where? Thanks
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Re: dash cluster capacitors
Ray -
They're radio noise suppression capacitors, and they reduce/prevent "pops" and static in the radio speaker, primarily on the AM band. All of them are shown in the U69 (radio) section in your Assembly Manual. -
Re: dash cluster capacitors
So all of these dash gauge capacitors are just for the radio and have no other electrical use (gauge protection etc?)
Thanks,Comment
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Re: dash cluster capacitors
They help a little with surge suppression also but the effect is minimal. For example, when the lights are turned on the electrical gauges needles can jump momentarily due to the current surge. That visual effect will be reduced. They don't protect anything.
The capacitors also help to reduce the alternator/generator whining sound which can enter the AM portion of the radio via the power or antenna wiring. Unshielded wiring is a transmitter antenna for generator brush noise. The capacitors short out that energy at low radio frequencies. Just another example of what John was describing.Comment
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Re: dash cluster capacitors
Thanks Jerry, If you notice there are (seems like) several different ones offered for different uses for the gauges, each itemized in the aftermarket catalogs. You woinder how much differance can there really be between them? Also, I have a larger in line type thats affixed to the underside of the steering wheel bracket, any idea where this little jewel goes? I do have the 67 AIM, but the drawings are damn hard to read!
Thanks,
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Re: dash cluster capacitors
Thanks for the information. As an aside, may I ask, on a non radio equipped 67, such as my 67 BB, did the guage cluster still get the capicitors? My car was a very low mileage car when we did the body off restoration and as I recall, no capicitors were found. Thanks for the help....Comment
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Re: dash cluster capacitors
I don't have any capacitors on the underside of my 67 steering column Ray. There's a wax cap just above the column but it's not hooked up (never noticed that before) and probably is there to filter the turn signal flasher. I dug out the AIM, illustrated parts manual and chassis manual but couldn't find what you described. And you're right, it's hard to find anything in those pictures.Thanks Jerry, If you notice there are (seems like) several different ones offered for different uses for the gauges, each itemized in the aftermarket catalogs. You woinder how much differance can there really be between them? Also, I have a larger in line type thats affixed to the underside of the steering wheel bracket, any idea where this little jewel goes? I do have the 67 AIM, but the drawings are damn hard to read!
Thanks,
Perhaps it was added later and is not stock?
My opinion on the differences you mentioned seeing in the catalogs is that the capacitors function the same as long as the voltage and microfarad ratings are identical. Lest you think I know more about the wiring harness connected capacitors than it do, I'm only fluent with their theory. I just repair/restore radios in the 53 to 94's. Capacitors in those devices do much more sophisticated tasks than just filtering noise. Amazing little devices for sure!
Finally, it's good to remember that all of these items generate radio noise to varying degrees -> wiper, headlight, heater and window motors, flashers, switches and even the static build up on tires (I include talk radio in this category also.
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Richards question (previous entry) regarding the capacitors associated with a radio delete is interesting. I noticed in the manuals that "AM/FM" and "Radio" capacitors seemed to be uniquely identified; perhaps to make deletion identification easier. There are several long time restorers I see around here regularly and I'll be sure to pass along anything I learn.Comment
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Re: dash cluster capacitors
Ray, instead of the steering wheel bracket are you referring to the wax capacitor that is attached to the pedal bracket? It plugs into the brake light switch and stops a popping sound through the radio speaker when you hit the brake.Comment
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Re: dash cluster capacitors
The RF caps are called out in the U69 radio option (back of the AIM book). They were 'intended' to be installed only on radio equipped cars (burden the cost with the option)....
But, with so many cars going down the line/out the door with radios, once in a while we see factory 'escapes' where the caps were added despite that particular car not having a radio...Comment
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Re: dash cluster capacitors
Bingo Bill! Thanks you very much!
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