| rogbell | -- 12-18-2010 @ 10:19 AM |
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I have a restored original '41 radio installed in my '41 Coupe Sedan which works perfectly as long as the engine is not running. As soon as I start the engine there is so much noise/static that you can't hear anything. I do not have a condenser mounted next to and attached to the voltage regulator and wonder if that is the problem. If so, what condenser do I need and where can I find one. Thanks.
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| Old Henry | -- 12-18-2010 @ 11:20 AM |
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Here are some ideas from the manual for the 46-48 radio that you might consider. (See attached image) I did not find the recommended condensers in the Green Bible so don't know what their rating is. Old Henry (The older I get, the better old looks.) This message was edited by Old Henry on 12-18-10 @ 11:45 AM
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| 4dFordSC | -- 12-18-2010 @ 11:35 AM |
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The modern equivalent of the condenser shown in the instructions posted by Old Henry is the RC-1, which NAPA carries.
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| Old Henry | -- 12-18-2010 @ 12:24 PM |
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4dFordSC, I'm assuming that the NAPA RC-1 is equivalent to the 22-1148 recommended for the circuit breaker panel and the voltage regulator. Do you know the NAPA equivalent for the 22-1326 recommended for the coil and maybe the oil gauge sensor? Old Henry (The older I get, the better old looks.)
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| Old Henry | -- 12-18-2010 @ 12:33 PM |
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I would also fully check out the antennae. If it is old, you might just want to get a new one. They can short out and lose their ground and cause the problems you're describing. I remember having those problem that were solved by replacing my antennae. I don't know how the '41 radio is installed so don't know if you have room to try this with the radio installed but if you can, try unplugging the antennae from the radio both with the engine running and not and see what, if any, difference it makes. If it makes no difference or is worse with it plugged in, most likely the antennae is bad and needs to be replaced. Old Henry (The older I get, the better old looks.) This message was edited by Old Henry on 12-18-10 @ 12:38 PM
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| supereal | -- 12-18-2010 @ 1:33 PM |
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What to do depends on then type of noise. A whirring noise that rises and falls with engine speed is usually caused by the generator and can be suppressed with a condenser on the armature terminal to ground. If it is sparkplug noise, resistor plugs may help, but probably won't eliminate much of it. Be sure you have a good ground strap between the body and the engine. As mentioned above, be sure the base of the antenna is well grounded, and that the antenna lead shield is intact and soldered. The noise mainly affects the AM radio band, and because most listened to local stations that were strong, it wasn't often a consideration years ago. Unless you must have the rightwing blather that dominates AM today, you might consider having your radio converted to AM/FM, as FM is not subject to the noise you have described. I did that years ago. The most careful efforts almost always fall short of fully removing the static.
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| 4dFordSC | -- 12-18-2010 @ 2:18 PM |
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My '40 with a stock Roto-Matic AM radio has RC-1 Condensers attached to the "Batt" terminal of the voltage regulator, the oil pressure sending unit, and the circuit breaker under the dash. The installation instructions also call for one on the coil in addition to the ignition condenser, but I omitted that one. I have no engine noise in the radio, but don't listen to it that often, since about all we get on AM in this market is talk radio and gospel music. Used to have a good Golden Oldies R&R station, but it went Hispanic several years ago:-(
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| supereal | -- 12-18-2010 @ 2:55 PM |
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If it does the job, that's OK, but the condenser at the regulator should be on the ARM terminal. The coil already has a condenser, usually at the distributor. It is part of a tuned circuit, and adding capacity may affect operation. We used to install condensers on the oil pressure sender and the gas gauge sender as part of the kit that came with the radio, but unless there is an intermittent "scratching" sound, they usually are not necessary. A condenser on the input wire to the radio may help, but we usually substitute a piece of RG-59 coax for that wire, such as used in TV systems, and ground the shield. Any part of the wiring in a car can pick up radio noise. That is why the Corvettes have shielded ignition systems.
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| Old Henry | -- 12-18-2010 @ 3:09 PM |
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Two responses to Supereal: 1. As I said before, I don't have any radio noise and have no condensers anywhere so don't know the difference between putting one on the ARM terminal of the regulator and putting it on the BAT terminal. All I know is that Ford recommended the BAT terminal as per my attached illustration. 2. The condenser by the distributor is to give the current trying to go through the points when they open an alternate route so that the points don't arc so much and burn out. Ford's recommendation is to put one on the other terminal BEFORE the current goes through the coil to dampen any static being picked up by that wire. (See illustration) What is unclear from those instructions and illustration is whether to put that condenser before the coil mounted resistor or after. Old Henry (The older I get, the better old looks.) This message was edited by Old Henry on 12-18-10 @ 3:13 PM
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| Old Henry | -- 12-18-2010 @ 3:16 PM |
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One more question for 4dFordSC: Do you know the NAPA part equivalent for the suppressor explained and shown in the radio manual as part number 63-1273? Old Henry (The older I get, the better old looks.)
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| 4dFordSC | -- 12-18-2010 @ 4:22 PM |
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"One more question for 4dFordSC: Do you know the NAPA part equivalent for the suppressor explained and shown in the radio manual as part number 63-1273?" Sorry, I don't.
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| supereal | -- 12-19-2010 @ 9:59 AM |
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OH: Putting a condenser on the battery post of the regulator has the same effect as putting one in the power wire to the radio. There is no problem with putting a condenser on the input side of the coil, but putting it on the distributor side will affect operation. The ignition condenser does dampen arcing of the points, but it also provides a method of assisting the charging and saturation of the coil, itself, so the capacity is important. All the Ford radio installation information I have shows the regulator condenser is attached to the ARM terminal if it is not actually on the generator. As said above, there is no harm to put one on the BATT post, but it won't suppress the arcing at the commutator, a major source of noise. For a couple of decades, I was employed as an engineer for a group of radio stations, and spent a lot of time trying to clean up AM interference on a variety of receivers, including vehicles. We could usually reduce it, but seldom eliminate it. The spread of FM radio made life a lot easier.
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| Old Henry | -- 12-20-2010 @ 11:09 AM |
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It looks like it wouldn't hurt to put condensers in all of the possible places (but not another between the coil and the distributor.) Might not do any good but can't hoit. Something I did to try to eliminate spark plug noise in my indepentent CD player (run by it's own battery not connected to the car except to the speaker) is to put choke cores on all lines that would fit in them. Here are the ones from Radio Shack I used: http://www.radioshack.com/product/index.jsp?productId=3012599 Here's ferrite core for larger wires: http://www.radioshack.com/product/index.jsp?productId=2103222&clickid=prod_cs The way those work is to run the wire through them then back around and run through again. That eliminates a different kind of noise that capacitors to not. Capacitors (condensers) reduce low frequency interference, coils reduce high frequency. Old Henry (The older I get, the better old looks.) This message was edited by Old Henry on 12-20-10 @ 11:22 AM
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| rogbell | -- 12-20-2010 @ 11:21 AM |
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Thanks for all the help everyone. I will try each of the suggestions and hopefully eliminate the problem.
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| Old Henry | -- 12-20-2010 @ 11:21 AM |
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Here's a photo of one of my wires going through the larger ferrite core. You can see in the photo two other smaller choke cores with smaller wires going through them. Old Henry (The older I get, the better old looks.)
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| supereal | -- 12-20-2010 @ 2:54 PM |
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Ferrite beads do a good job on higher frequencies, but not much on AM noise. In old radios, much of the noise is due to the mechanical vibrators that generate the higher plate voltage from the 6 volt input for tube type radios. There are solid state "vibrators" that help with that, and don't create "hash". Another common fault is old filter capacitors. They are mostly electrolytic type, and become weak due to aging. One method of noise reduction tried years ago was to use the speaker coil as a choke by running the input thru it. They are rare today.
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