Jump to content

Stock AM Radio noise suppression condensor


Recommended Posts

Ok, im trying to get my stock AM radio working. The head unit is good, and when I was in Canby, OR I had good reception and nill static.

 

Back in canada, not so much. I tried putting a condenser on my alternator, however; it seems to draw excess power for the first minute of turning on the engine. it keeps my charge light on and i can hear a "whine" from the voltage regulator? but the radio is ok, some times i have to turn on the headlights.

 

Then there is the condenser on the + side of my coil, i think thats done, very rusty. I have tried the new condenser on the coil and I get so much static, so thats not right.

 

There is also a condenser on my distributer, thats new.

 

I cant find much info in my manual or online (datsun wise) I saw a picture of a 240z ALT with a condenser on it, but couldnt tell if it was on the positive or negative. 

 

Im going to have to buy a new condenser for the coil, because i cut the terminal off, and put in on the new one (fork vs blade)

 

Thanks!

Link to comment
  • Replies 11
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Make sure you have good quality resistance plug wires.

 

Make sure you have an R on the plug number. Such as BR6ES

 

Check or instal a ground wire from the negative terminal to the body sheet metal. Or from the block to a hood hinge bolt

 

A condenser will not draw any power from the alternator. Think of it as an extremely small storage battery. If your light is now staying on and the regulator is humming this is not right. What capacitance did you use? An alt capacitor (or condenser) should be no larger than the tip of your thumb. It's polarity is important and it should show infinite resistance across it. Maybe yours has an internal short.

 

Alternator.... 0.5 micro farads

Dizzy........... 0.2 to 0.24 micro farads

Link to comment

the fuse that feeds my Am radio had a coilwound in there as a suppression.

 

be honest the condenser I think you don't need esp if you went elelctronic ignition or Pertronix as I did.

 

maybe bad antenna conecction.

 

I use NGK pklug wire set NE64

 

 

Condensor on the dist is for the points so it helps stop the arching.

 

If you still using points hopefully you still using the ballast resisitor and a Point coil.  if not he coil will be HOT

Link to comment

Sadly I still have points. Its a new coil and I have a new ballast with it too. The condenser on the dizzy in new too.

 

I will try the wires. Now that it's warmer, outside and truck running, it's actually working ok. It doesn't seem to work when the truck is cold. Voltage regulator maybe? Idk

 

My antenna is garbage, it got snapped off half way and I have a coat hanger in there. But when the trucks off it gets good service so it's not the antenna.

 

I'll buy the plug wires because I didn't check last set I got :(.

 

Oh I also have that coil in the fuse holder for the radios power.

Link to comment

 But when the trucks off it gets good service so it's not the antenna.
 

well maybe the Datsun Ant has built in suppressor unlke your coat hanger. Im only guessing. remember its like a coax connector on there as there is a shield.

 

 

 It doesn't seem to work when the truck is cold.????

what does this mean? maybe radio is just bad until it warms up.

 

 

The spark plug wires Im only guessing also I never had a proplem with any of them. But the NGK s look so cool.

Link to comment

The antenna was hollow. No more than a extending magnet wand. But I get what you're saying.

 

Cold as in, early morning. It's getting to be 10 deg at night. But then again it works on a "whenever" basis. Sunny, rainy, night, day. It's not consistent enough I can pin point it.

 

The auto part guy said every plug wire is shielded these days. It was more common back in the day. Unless I am looking for RESISTOR wires? Not just shielded? But even then my wires say suppressed or the like.

Link to comment

The stock AM radio is sensitive to signal strength.   Inside the radio is a AGC, or automatic gain control circuit.  This circuit makes the radio more sensitive, when the radio signal is weak, and less sensitive when the radio signal is strong.

 

If your antenna is not good, in essence every radio signal is weak.  The radio turns the AGC "up" trying to get any signal.  This amplifies the radio station signal, but also amplifies the sources of RF interference from the truck.

 

The Stock AM radio probably also has an antenna trimmer.  This is a screw that tunes the radio to the antenna length, and the cable from the antenna, to the radio.  this tuning also makes the radio signal stronger, and tends to reject sources of interference.

 

Get a good antenna.  Tune it to the radio with the trimmer.  This is how, according to my 1970 Nissan service manual.

Extend the antenna completely.  Turn the radio on, tune to 1400 KC. You may have a strong radio station at that frequency, tune away from it.  once that is done, turn the antenna screw to the left, and right slowly, listerning to the noise, or static in the speaker.  stop at the point the noise is the loudest.

 

It was suggested you check the secondary ignition wires,  Make sure they are in good condition, Cap and rotor too.  Use the resistor spark plugs.

For ignition noise, install a 0.5 UF capacitor on the POSITIVE side of the ignition coil.  Try to keep the lead to the capacitor as short as possible.

For alternator noise. A whine, that increases with RPM, install a 0.5 UF capacitor on the main output charging tewrminal.  Try to keep the lead to the capacitor as short as possible.

Link to comment

The old Radio Shack became The Source? something like that. They used to have tons of parts but now are just cell phone and crap outlets. Source will have some parts. Phone 'em up

 

Mission Park Shopping Ctr

#11/12 3151 Lakeshore Rd

Kelowna BC, V1W 3S9

(250) 860-5531

 

Orchard Park Shopping Ctr

2271 Harvey Ave Unit #910

Kelowna BC, V1Y 6H2

(250) 860-6865

 

 

Canadian Tire used to have bolt on antennas for radios but now a days....???.

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.