Radio Noise-Original AM - Vintage Mustang Forums
 6Likes
Reply
 
Thread Tools
post #1 of 31 (permalink) Old 08-31-2019, 07:52 PM Thread Starter
Senior Member
 
Fitch's Avatar
 
Join Date: Aug 2019
Location: Fort Worth, Texas
Posts: 178
Radio Noise-Original AM

This just started yesterday. I recently re-capped my original AM radio and it has been playing great. Yesterday, I started hearing a motoring sound, not a whine, coming through the radio especially with the AC compressor on. Talking gets a bit distorted too. There is no noise or distortion when the engine is not running. There is a radio suppressor next to the voltage regulator that I substituted a .5 mf cap with but there was no change. Anybody got any ideas? Thanks, ,Cliff

PS: The noise may coincide with the repair I made yesterday to the amp meter wire near the starter solenoid. The noise is not a RPM whine and does not change with engine speed. Also, it was doing this before I snapped the mast off of my antenna which I also repaired. Reception is very good and I have adjusted the trim on the radio. FYI: I do not have the rear mounting strap on the radio. It was missing. Possible bad ground?

Cliff
1966 Blue Hardtop. 200 CID with 3 Speed Trans

Last edited by Fitch; 08-31-2019 at 08:14 PM.
Fitch is offline  
Sponsored Links
Advertisement
 
post #2 of 31 (permalink) Old 08-31-2019, 08:24 PM
Senior Member
 
myfirstcar66's Avatar
 
Join Date: Jan 2019
Location: Auburn University, Alabama
Posts: 1,311
Garage
Yes bad grounds are a culprit it seems more often than not when something has been either sitting a long time or recently disturbed.

My 1st car...
'66 Tahoe Turquoise/ Aqua coupe
•289 / 4100 •C4 Auto •Disc Brakes
•Dual Exhaust •Quick Manual Steering
•Rally Pac •Console •Deluxe Belts
•LOTS of Rotunda accessories

Older son's 1st car...
'66 Emberglo / Parchment deluxe coupe
•289 / 2100 •C4 Auto
•Dealer A/C • Console
•Dual Exhaust • Power Steering

Younger son's 1st car...
'66 Nightmist / Blue & white deluxe coupe
•289 / 2100 •C4 Auto
•Factory A/C •Console
WAITING FOR RESTORATION

myfirstcar66 is online now  
post #3 of 31 (permalink) Old 08-31-2019, 08:27 PM
Senior Member
 
Woodchuck's Avatar
 
Join Date: Mar 2001
Location: Peoples Republic of Vermont
Posts: 33,152
Send a message via Yahoo to Woodchuck
Maybe picking up interference from the IVR?

Bart

What, me worry?
- Alfred E. Neuman

Woodchuck is offline  
 
post #4 of 31 (permalink) Old 08-31-2019, 08:30 PM Thread Starter
Senior Member
 
Fitch's Avatar
 
Join Date: Aug 2019
Location: Fort Worth, Texas
Posts: 178
Quote:
Originally Posted by Woodchuck View Post
Maybe picking up interference from the IVR?
What is IVR ?

Cliff
1966 Blue Hardtop. 200 CID with 3 Speed Trans
Fitch is offline  
post #5 of 31 (permalink) Old 08-31-2019, 08:32 PM Thread Starter
Senior Member
 
Fitch's Avatar
 
Join Date: Aug 2019
Location: Fort Worth, Texas
Posts: 178
Quote:
Originally Posted by myfirstcar66 View Post
Yes bad grounds are a culprit it seems more often than not when something has been either sitting a long time or recently disturbed.
I tend to agree. I suspect a bad ground. Does the support strap on the radio act as a ground strap? Does the antenna base need to be grounded to the fender? Any other grounds I should suspect?

Cliff
1966 Blue Hardtop. 200 CID with 3 Speed Trans
Fitch is offline  
post #6 of 31 (permalink) Old 08-31-2019, 08:32 PM
Senior Member
 
Woodchuck's Avatar
 
Join Date: Mar 2001
Location: Peoples Republic of Vermont
Posts: 33,152
Send a message via Yahoo to Woodchuck
Instrument Voltage Regulator. Little silver thingy screwed to the back of the instrument cluster that turns 12VDC into 5VDC but switching on & off at a constant rate.

Bart

What, me worry?
- Alfred E. Neuman

Woodchuck is offline  
post #7 of 31 (permalink) Old 08-31-2019, 08:39 PM Thread Starter
Senior Member
 
Fitch's Avatar
 
Join Date: Aug 2019
Location: Fort Worth, Texas
Posts: 178
Quote:
Originally Posted by Woodchuck View Post
Instrument Voltage Regulator. Little silver thingy screwed to the back of the instrument cluster that turns 12VDC into 5VDC but switching on & off at a constant rate.
Hmm. Ok. Hadnt thought of that. Another thing I was thinking. When I got the car, the radio was a broken Custom Autosound that I tossed and replaced with this original . They had the CAS radio wired directly to the battery with an inline fuse so, I didnt know which wire the original radio was fed with. I just selected a 12 volt keyed source that wasnt being used behind the cluster and connected it there. I wonder if a different 12 volt power source would make any difference?
Woodchuck likes this.

Cliff
1966 Blue Hardtop. 200 CID with 3 Speed Trans
Fitch is offline  
post #8 of 31 (permalink) Old 08-31-2019, 08:45 PM
Senior Member
 
Woodchuck's Avatar
 
Join Date: Mar 2001
Location: Peoples Republic of Vermont
Posts: 33,152
Send a message via Yahoo to Woodchuck
Try the 14A Accessory fuse. You can get a "piggyback" connector...

Fitch likes this.

Bart

What, me worry?
- Alfred E. Neuman

Woodchuck is offline  
post #9 of 31 (permalink) Old 08-31-2019, 08:45 PM
Senior Member
 
NEFaurora's Avatar
 
Join Date: Dec 2007
Location: Melbourne, FL
Posts: 8,852
Send a message via AIM to NEFaurora
Try using the actual Radio Suppressor that was meant for the car at the VR. You can buy them from Virginia Classic Mustang's (VCM) website.

There was also a Secondary Radio Suppressor and its hard to find today. It was located underneath the Wheel hub Dust cap and would work while the car was in motion.

1965 Mustangs also had a Radio Suppressor on the back of the Alternator. (Pictured Below) It was deleted on 1966 and later Alternators.

)

Tony K.
Attached Images
File Type: jpg Picture20067.jpg (513.1 KB, 4 views)



Tony Kovar
Melbourne, FL (Formerly from Long Island, NY!)

1965 Mustang Convertible 200cid I6, 3spd Manual (Soon to be swapped for a '65 Date Coded C4!)
1966 Mustang Sprint 200 Registry Owner/Moderator
1966 Mustang Sprint 200 Convertible 200cid I6, C4 Auto
2007 Mustang V6 Convertible w/ Pony Package
MCA#70001

Getting Ready for the 2020 Melbourne, FL MCA Nationals!

Last edited by NEFaurora; 08-31-2019 at 08:48 PM.
NEFaurora is offline  
post #10 of 31 (permalink) Old 08-31-2019, 08:51 PM Thread Starter
Senior Member
 
Fitch's Avatar
 
Join Date: Aug 2019
Location: Fort Worth, Texas
Posts: 178
Quote:
Originally Posted by NEFaurora View Post
Try using the actual Radio Suppressor that was meant for the car at the VR. You can buy them from Virginia Classic Mustang's (VCM) website.

There was also a Secondary Radio Suppressor and its hard to find today. It was located underneath the Wheel hub Dust cap and would work while the car was in motion.

1965 Mustangs also had a Radio Suppressor on the back of the Alternator. It was deleted on 1966 Alternators.

)

Tony K.
I am using the factory radio suppressor at the VR. I sub'd a .5 mf cap in its place as a test to see if the original was good or bad. It made no difference. I would expect a whine that would increase with RPM if it needed a suppressor at the alternator. Also, it doesnt matter if the vehicle is in motion. Just running while sitting will produce the noise.
Woodchuck likes this.

Cliff
1966 Blue Hardtop. 200 CID with 3 Speed Trans
Fitch is offline  
post #11 of 31 (permalink) Old 08-31-2019, 08:58 PM
Senior Member
 
NEFaurora's Avatar
 
Join Date: Dec 2007
Location: Melbourne, FL
Posts: 8,852
Send a message via AIM to NEFaurora
Maybe the new caps have no shielding? I have no idea. You might try some shielding material inside the radio...What have you got to lose...

)

Tony K.



Tony Kovar
Melbourne, FL (Formerly from Long Island, NY!)

1965 Mustang Convertible 200cid I6, 3spd Manual (Soon to be swapped for a '65 Date Coded C4!)
1966 Mustang Sprint 200 Registry Owner/Moderator
1966 Mustang Sprint 200 Convertible 200cid I6, C4 Auto
2007 Mustang V6 Convertible w/ Pony Package
MCA#70001

Getting Ready for the 2020 Melbourne, FL MCA Nationals!
NEFaurora is offline  
post #12 of 31 (permalink) Old 08-31-2019, 09:00 PM Thread Starter
Senior Member
 
Fitch's Avatar
 
Join Date: Aug 2019
Location: Fort Worth, Texas
Posts: 178
Quote:
Originally Posted by NEFaurora View Post
Maybe the new caps have no shielding? I have no idea. You might try some shielding material inside the radio...What have you got to lose...

)

Tony K.
Could be but there was no noise for several weeks after I recapped it. Its going to be fun figuring this one out.

Cliff
1966 Blue Hardtop. 200 CID with 3 Speed Trans
Fitch is offline  
post #13 of 31 (permalink) Old 08-31-2019, 09:19 PM
Senior Member
 
NEFaurora's Avatar
 
Join Date: Dec 2007
Location: Melbourne, FL
Posts: 8,852
Send a message via AIM to NEFaurora
Could be the Antenna too maybe... Try using one of those "Hide away" Antennas and see if the humming goes away.....

If not, Maybe the car's ignition system?.....Move over to Pertronix??!??....lol.... Shooting in the dark here....lol....

)

Tony K.



Tony Kovar
Melbourne, FL (Formerly from Long Island, NY!)

1965 Mustang Convertible 200cid I6, 3spd Manual (Soon to be swapped for a '65 Date Coded C4!)
1966 Mustang Sprint 200 Registry Owner/Moderator
1966 Mustang Sprint 200 Convertible 200cid I6, C4 Auto
2007 Mustang V6 Convertible w/ Pony Package
MCA#70001

Getting Ready for the 2020 Melbourne, FL MCA Nationals!
NEFaurora is offline  
post #14 of 31 (permalink) Old 08-31-2019, 09:21 PM
Senior Member
 
Join Date: Jul 2009
Location: Niceville Fl
Posts: 4,593
Bad solder joint on one of the replacement caps?

Btw what caps did you use? And lessons learned? I need to recap my am/fm

Flade
68 289 convertible Candy-apple red & white
66 200 coupe Blue
94 GT convertible Red & black
98 GT convertible White & black
98 V6 convertible White & tan


Last edited by Flade; 08-31-2019 at 09:33 PM.
Flade is offline  
post #15 of 31 (permalink) Old 09-01-2019, 06:57 AM Thread Starter
Senior Member
 
Fitch's Avatar
 
Join Date: Aug 2019
Location: Fort Worth, Texas
Posts: 178
Quote:
Originally Posted by Flade View Post
Bad solder joint on one of the replacement caps?

Btw what caps did you use? And lessons learned? I need to recap my am/fm
A bad or cold solder joint would produce the noise with just the key one and engine not running.
Ive been restoring antique tube and early transistor radios for about 25 years so I have accumulated a huge stash of new capacitors and resistors. I also bought all of the ones my local Radio Shack had when they were closing. There is nothing mysterious about re-capping these radios. Its pretty straight forward. Go slow, match the value on the original cap as close as possible. Its OK to go slightly higher than the marked value but dont go below that number. At least 1 cap will have 2 caps in one can. Those are electrolytic capacitors and the most important. Before you remove that cap, note the orientation of it and study the information that is stamped on the can. I have not recapped a FM car radio so, I would expect several more capacitors. Is your radio currently working OK ? If so, I would leave it alone until the volume or clarity starts to diminish . Good luck!

Cliff
1966 Blue Hardtop. 200 CID with 3 Speed Trans
Fitch is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Vintage Mustang Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are Off

 
For the best viewing experience please update your browser to Google Chrome