Ever sine I have had my '66, The radio has never been quite right. It has always sounded fine with the volume down, but as I turned it up, it started to get scratchy and distorted. At high volume you couldn't make anything out.

I tore it apart and replaced the two capacitors and added an aux port. The quality didn't change so I decided the speaker must be bad.

I ordered a new 8 ohm replacement speaker and just got around to installing it today. Much to my disappointment, it still does the exact same thing.

Good sound down low, but gets worse as you go louder.

Engine running makes no difference.

Is there something else in the radio that I need to replace?

 

Reception, and selection of radio stations in my area is extremely limited, so the radio in the 65 is strictly for show. Topic has come up on occasion and seem to recall member posting thread on retro fitting, or upgrading original radio's w/ current electronic components. Suggest run FTE search on topic and narrow the search to the 61-66 forum and find thread with other member's comments.

Came across this thread: https://www.ford-trucks.com/forums/1...d-truck-2.html

OE Style Radio with AM/FM, Bluetooth, USB & Ipod/Iphone - 66-77 Ford Bronco, New - Toms Bronco Parts

Anyhow food for thought???

 

Is there a way to tune the antenna?

 

Sounds like the potentiometer behind the volume **** is acting up. Unless it's routinely rotated throughout its range, the contacts get oxidized. You can remove the potentiometer and soak it in contact cleaning solution, or just try to hit it with some aerosol electronic contact cleaning spray, hoping that some gets inside and does the job.

Forums devoted to antique radio and electric guitars have lots of tips & tric ks for cleaning dirty "pots".

 

Certain Jimkoz is lot more knowledgeable than I on subject; having said that, I used an aerosol can of electrical spray and it damaged the plastic components and ended up I had to replace the entire switch. Anyhow, food for thought??

 

You can use this stuff that I use for vintage stereos

 

Brake cleaner and other no-residue solvents will often do a real number on plastic. Vintage pots are usually cleaned with WD-40, and tho purists cringe nobody has come up with anything better for that specific purpose.

Make sure you've actually replaced the power supply capacitors - are there any electrolytic types? Those will need replacing.

 

I did everything that was done in here:

https://www.ford-trucks.com/forums/1...-addition.html

How do I get to the potentiometer to clean it? It is inside the volume switch, correct?

 

Neat thread! Usually volume pots have a couple holes in the back that will allow spraying contact cleaner inside. Don't go overboard about it, but don't be shy either. Put a shop towel down to catch excess and spray a healthy dose right inside the pot and work the volume control several times. It will get where it needs to go. Any other switches and pots should be cleaned up too.

If cleaning the volume control doesn't fix the problem and you're still wanting to troubleshoot dig around the net for a schematic or SAMS folder.

 

If you look at the pictures in that thread. See that big silver can? There are at least two more capacitors in that as well, tough to read but looks like a 400 uF and 300 uF (MFD) @ 16 volts. If you can find one that's close in voltage and uF it would be quicker to replace. If not, use discrete caps. For replacements, don't go less than 16 volts and get as close as you can on the MFD/uF. Two 500 uF @ 25 volts would be fine, for example. Sometimes the older stuff doesn't have an exact modern equivalent but that's no problem. Just be sure to observe polarity, and note whether the can itself is grounded to chassis or "floats" above ground, don't connect replacement capacitors to chassis if the outside of the can wasn't.

it looks to me those are probably the main power supply capacitors. That would likely be the source of the problem? Dirty pots can cause issues with noise, but not usually overall volume.

 

I finally have a little time on my hands so I'd like to have another go at this. I see the big round 300 uF capacitor. Where is the 400 uF capacitor? Are the two big rectangular-ish silver thingys capacitors?

You also make mention of electrolytic type capacitors. How do I tell if they are? and do they have to be replaced with electrolytic types or will any capacitor with the correct uF and voltage rating work?

I know very little about this type of electronics, but that is why I am trying to fix the radio myself - it helps me learn new stuff and makes me feel like a bad a$$ when it actually works.

 

Do you want me to scan and send you copies of the SAMS and Bendix schematics? I have both for the 6TB* radios. The biggest silver can is 2 capacitors in one. 400mf and 300mf at 16 volts in the one unit. There are two other electrolytics rated at 500mf (2V) and 50mf (3V).


Read this carefully and you can not only fix your radio but add a hookup for your smartphone or MP3 player, too, if all goes well.


Adding Auxiliary Input (for an mp3 player) to an Old AM Truck Radio


Let me know if you'd like a copy of the schematics. The two rectangular silver thingies are tunable coils. There is a screw slot in the top of each so you can adjust them. But only adjust them while observing with an oscilloscope. You want to adjust them both to 262.5KC if they need a change. This is the intermediate frequency (IF) which is between the Radio Frequency (RF) portion and the Audio Frequency (AF) portion.


Chad


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1972RedNeck, the big silver cans have more than one capacitor inside. Up to 3 or 4 typically. They are electrolytic capacitors, meaning they have a polarity, and a very high capacitance to size ratio. You COULD replace them with regular capacitors but they would each be the size of a coke can and cost a small fortune.

Think of them like a battery. They wear out, lose ability to take a charge, etc. You can use individual, discrete capacitors of the same or greater voltage rating and capacitance to replace the sections inside the can capacitor. This is fairly inexpensive. Use new manufactured electrolytics, not NOS. You may find, if you dig, a twist-loc FP replacement can for the old one. They are convenient, but relatively expensive. Maybe 20 or 30 dollars. Check eBay for a quick survey of what's available.

 

Yes, and they can hold a charge for quite a while after being disconnected from power. Discharge them first using a 100 ohm resistor across the leads.


It is possible to re-form older NOS capacitors using a Capacitor Checker like the IT-28 from Heath, but avoiding them otherwise is good advice for sure.


Heathkit Vintage Capacitor Checker


I have one of these on the bench here. Great old testers.


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Eh, the ones in his radio ceased to be a hazard about 30 years ago, they probably won't hold a charge anymore. That's why they need replacing, basically.

It's good advice to beware the hazards that electronics can pose, of course. For the most part auto radios though aren't going to be much of an issue.

I have an Eico 950B iirc, with tuning eye. Can test capacitors with up to 500 volts DC. Now *that* thing is dangerous. See the metal case there, it will be "hot" either when ON, or OFF, take your pick, and can still zap ya with the DC too. Keep one hand in back pocket at all times. It works well though. These came as kits too, lots of cool stuff available back when electronics were big enough to see or handle.