How To Repair and Diagnose Problems with Your Imperial's Solid State Radio 


Imperial Home Page -> Repair -> Accessories -> Radios -> Solid State

Tip from Kerry (1973 radio removal):

Removing anything under the dash on a 72-73 is a real pain but it can be done.

1- Get a good flashlight that will stand up by itself.

2- Put on some good safety glasses as 'stuff' will fall down in you eyes.

3- Open the passenger door and move both seats as far back as possible

4- Remove the AC duct that goes from the center plenum directly below the radio to the drivers side. There are two phillips screws one on each end of the 3' long plastic piece. The left side drops down and you can then pull it out.

5- Remove the flex hose from the right side of the plenum. It slips off like a dryer vent.

6- Remove 5 - 5/16 screws that hold the AC plenum in. There are three on the bottom and one at the upper corner of each side. The upper ones are a bear to get to. It takes a stubby nutdriver or a 1/4 ratchet with a short extension.

7- As soon as you get the plenum out, you can see and get to the radio and the clock.


Question from Rich:

Does anybody know a good place to send my radio AM/FM out of my '66 Imperial Crown. It will play, but the station always drifts, and you have to constantly reset the station. I also have a problem with the radio in my '79 Lincoln Town Car. It has a loud hum coming from it will you're on the higher bands.

Replies:

From Jan:

I had Bob's radio in Pismo Beach, CA redo the AM radio in my '55 and it works perfectly. The owner is now Dan and his phone is
(805)773-8200. If you have the chance his shop building and it's contents are a trip back in time.

From Richard:

George Found
Grandpa's Radio Shop (he's not the Grandpa, he just works on your Grandpa's radios (and TVs - pre-1960 only)
26 Queenston Crescent
Kitchener, Ontario N2B 2V5

519-576-2570

George has done radios for me for two 1961 Cadillacs, a 1958 New Yorker Town & Country, a 1968 Chrysler Town & Country and a 1958 Packard Coupe. On the '58 Packard, George even turned the yellowed plastic buttons back to their original white, with some pretty delicate sanding. On the '58 Chrysler, George left his booth at the Canadian equivalent of Hershey and walked with me to the opposite side of the flea market to confirm my suspicion that I had just discovered the correct 7-button Electro-Touch tuner for the '58 Chrysler, which he took home to rebuild for me, so I could do a "hot-swap" later. He's also rebuilt a few speakers for me, when needed.

The 1968 Imperial convertible that I just purchased (yes, Virginia, there IS some Imperial content) has an inoperative radio, though the factory 8-track works great, so George will be doing that one for me, over the winter.

So, Rich, I can highly recommend George's services and if you prefer to send it to me, I'd be happy to take it to George's shop for you, since I'm going there anyway. (He has an amazing collection of early radios and pre-war TVs, and phones that go back to the wooden ones, so a visit there is always interesting.)


Question from Mark (1963):

I cannot tune the radio in my '63 Imperial. I removed it on the weekend, and have since removed the cover plates and am fascinated by the mechanisms, tubes, and circuitry in this simple am radio. The tuning mechanism moves via the pushbuttons, yet if I try to manually or electrically ( via footswitch) tune the radio there is no movement of the tuning mechanism. Before I get too carried away overhauling the radio to find the problem I thought I would check and see if anyone has gone through a similar repair and could offer any tips.

Replies:

From Philippe:

I don't know if '63 and '57-'58 radio are the same but I've repaired my '57-'58 radio which had a similar problem. First you don't say if you can tune the radio on a station with the manual "tuning" knob. The pushbuttons (and tuning knob) are a manual affair but the first thing is to have a radio working "manually". The "search tune" automatic system is a lot more complex affair:  There's a relay or solenoid, a small motor which drives the tuning shaft, a reversing switch and a magnetic clutch!! I repeat, this is what I've found in a '57 radio (with the schematic on the cover). The solenoid/relay (operated by the foot switch or the bar) controls the motor and the clutch. In fact it's a dual solenoid with a "starting" and a "holding" coils. When the holding coil is "on" the motor (via the magnetic clutch) drives the tuning shaft: you see the knob turning! When you reach a station, the strength of the radio signal disconnects "starting" coil and connects "holding" coil, so clutch and motor are "off". When you reach the end of travel w/o stopping, a reverse switch operated the motor in reverse. Problem on my radio was the relay/solenoid, but it was 4 years ago and I don't remember well what I did! I think I replaced it with another relay (non original ..) and cleaned the magnetic clutch and motor. Note that I have simplified the explanations as there's also a "local/distance" switch, a trigger tube etc...

From Dick:

As someone else has commented, it isn't exactly clear what you mean by "manually". If you mean manually pushing the "search tune" bar, that is the same electrically as tapping the foot control switch. If you mean manually turning the station selector knob, then you do indeed have a slightly more complex problem.

In either case, note that the shaft which runs laterally through the chassis and which actually positions the tuning slugs in the variable inductors is in fact joined to the drive mechanism by a slip clutch all the way at one end of the shaft. This is probably slipping. If you grab the rotating part and turn it yourself, you can probably tune the radio. The push button station selectors bypass all this folderol, and rotate the tuning shaft directly, so it is a given that the radio can still be tuned with the push buttons long after the other mechanisms fail.

Sometimes you can repair the slipping drive clutch by careful cleaning of it's surface, along with lubrication of all the moving parts in the mechanism. You must use only a tiny drop on most places (I put a dime sized puddle of "clock oil" on a smooth surface, and dip a straight pin into it to pick up microdrops of oil for each moving part.) There is an adjustment on the clutch engagement pressure/motion, but it has really limited range.

Before you get involved in all that, note that if you are careful, you can push two push buttons at once, and with a kind of see-saw motion, move the dial smoothly across the band until you find a station. Then you can find out if the radio works at all, regardless of the tuning funnies. If it doesn't, it has to go to a radio repair shop anyway, and my advice is to just ship it off to one of the specialty vendors you'll find in Hemmings (or perhaps on the IML vendor list.) I used to fix these for people, but nowadays I've too many projects already, so I'll pass.

By the way, while the radio is merely an AM radio, it is anything but "simple". It was this "Wonderbar Tuning" design, patented by Delco, which took over the luxury car radio business from Philco (then my employer) in 1949. The design of the mechanism and the control system for it was and is quite sophisticated indeed. It is amazing that most of them still work after 50 years! The non-luxury car radios were indeed "simple" in those days, but not this puppy!


Question from Allan (1964):

I was advised that the reverberator was located at the back of the trunk -- behind a piece of black cardboard. My mechanic tore the trunk apart -- no reverb. I even had him trace the rear spraker wires in an attempt to find the errant box. Result -- the reverb is still messed up. Could someone give me an idea where else it may be? On my '64 Newport it was mounted from the rear package shelf. Try to imagine what that was like over railroad tracks!!!! Lastly -- I sure would like to locate an AM/FM radio for my '64. Any ideas?

Replies:

From Greg:

Mine is located behind the dark gray cardboard under the trunk lip by the latch. I own a 1964 Crown, so I assumed yours would be too. I did not mean to mislead, perhaps there was a midyear change, or yours has been removed?

From Ken:

The reverb unit is in the trunk on the right (passenger) side. It is silver (metal) finish and about 4 inches wide and about 10 inches long. It is behind the rear trunk trim panel and the wires run along the passenger side of the car under the threshold trim plate to the radio. It is not hard to miss once you have the trim removed from the rear trunk compartment. I have also seen some of these units installed under the rear package tray in the trunk. I think that this was when they were dealer installed. It all wires in the same way and includes the rear and front speakers. My '65 Tbird Special Landau uses the same unit and Ford called it Studio Sonic.


Question from Mark (1964):

Is their anyone in the club that can direct me to a contact for AM radios? I know this might seem somewhat odd -- but my town has an excellent AM radio station. It plays soft rock, standards and jazz. The mix is totally appropriate for my 64 Imperial. I am also interested in obtaining a power antenna. Lastly -- a schematic of the factory reverberator. Any help would be greatly appreciated.

Reply from Nicholas:

For your "am radio" for the 1964 Imperial, suggest you try this kind, knowledgeable person (although a bit of a distance from you): 

Keith Campbell 

1980 Foxgate Road 

Mobile, AL 

36695 

Sorry, but do not remember his eMail address. He was helpful in obtaining the am/fm & reverberator brochures (repair manuals) for my 64 Crown; he is prompt, exact, and willing to help. Try him, if you have the time. I found it worth it!


Question from Mark (1965):

I'm having trouble with ignition/radio interference. The FSM shows a noise suppression capacitor attached to the positive side of the coil. Mine, of course, is gone with the wind. Does anyone know of a source/workaround for replacing this capacitor?

Reply from Dick:

Any ignition condenser (the type that is inside the old fashioned point/condenser distributor - remember those?) will do this job. Just go to NAPA and ask for an ignition capacitor for your 1965 Imperial, and install it from a solid clean bright metal mounting point, with the center connection to the + side of the coil. Keep the leads short.

Another reason for this noise, by the way, if the car has ever been repainted, is that the grounding clip from the near the hood hinge has been removed and not re-installed. You can picture the body man looking at this strange looking alligator toothed springy thingy, and saying "what the heck is this thing for" and throwing it away. There was a reason that was on the car, and the reason is that if you don't ground the hood, it re-radiates the electrical ignition noise right into your radio antenna.

Follow-up question from Bill:

If the grounding clip from the hood has been removed (as mine has), how does one go about re-grounding the hood?

Reply from Dick:

The easy way is to find one of those braided grounding straps that look like miniature versions of the old style battery ground cables - the flat woven braid type. Many cars use these to ground the engine to the firewall (for the same reason, by the way). I know they are usually found on GM cars, and Packards, and probably many others. You don't need a really big one, a 3/8 or so width to the braid is adequate. Just install it from a hinge bolt on the hood (being sure that there is bare metal contact to the hood structure) and put the other end to the firewall with as short a lead as you can arrange and still be able to open the hood. The closer you locate this to the radio antenna, the better it will work. After you tighten the bolts, you can paint over the connection to prevent future corrosion or rust, but make sure you have metal to metal contact underneath the paint!


Question from Dan (1966):

Does anyone know of a good, reputable repair shop where I can send my AM/FM radio and get it overhauled so it will work as close to new as possible?? I know there are a lot of places listed in Hemmings and such magazines but was wondering if any of our IML members have first-hand experience with any place in particular?

Reply from Dick:

If you want it to work like it did when it was new, almost any competent repair shop can do that for you - I used to do so for friends, but I retired years ago.

If you want it to work like a new one (note slight change in wording), you'll have to have it converted to modern innards, with quartz lock tuning, low noise front end, digital display, stereo audio system etc. Many of the shops you noticed in Hemming's also do this work, but it is more expensive.

What's the difference, you ask? The older technology FM radios do not have the stability to lock on a station and stay there over hill and dale, they do not reject multipath distortion (Donald Duck voices when you pass buildings or mountains), and they cannot lock on extremely weak signals such as those in areas more than 100 miles from the transmitter, and they have no "capture" technology, which allows them to lock onto one station even though a signal from another station is bleeding into the same channel. The result is very unsatisfactory operation of the FM section unless you live within 50 miles of the transmitter, and never move the car.

The difference for AM operation is smaller, but still annoying, because the older technology will drift off the station due to vibration or temperature effects, giving you distorted audio at times, and they are harder to tune accurately.


Question from Tom(1966):

The owner's manual states that the search tune is available as an option for AM/FM radios (page 22), but the service manual states (page 1-13) that only the AM model is available with search tune. What is the correct information??

Reply from Dick:

AM-FM, perhaps, but not "Stereo" - that didn't come out in Imperials until late '67, and was listed as an available option starting in 1968. The AM-FM Stereo radios were not search tune, even in '68, but the much more common AM-FM radios were, in both '67 and '68. I don't know if the AM-FM in the '66 were search tune, but I don't see why they wouldn't have been.

Follow-up question from Greg:

My '65 Crown convertible is pretty well optioned and it has the AM/FM search tune radio with the remote button on the floor. Was this a rarely installed opton in '65? How far back was this radio available? I wish my car had the reverberating rear speaker! Is this something that can be added or did that option have to be installed at the factory? Why did Imperial not receive AM/FM stereo until late '67? My '66 Eldorado has AM/FM stereo but no search tune button either on the radio dial or on the floor. I would have thought The Big Three luxury cars of that era would have been neck and neck regarding technological advances such as "stereophonic sound" from a car radio.

Reply from Gene:

According to the Option Sheet for 1965:

Order Code 445 AM/FM radio w/ Power antenna and rear seat speaker
Order Code 447 Golden Touch Tuner - AM Includes Power Antenna and rear seat speaker
Order Code 466 Reverberator unit for rear seat speaker (with radio only)

Reply from Dick:

Floor operated station changers go back into the '30's (my 1939 Packard Limousine had this feature), but those were not true search tune radios - they merely cycled through 6 preset stations, one each tap on the floor button.

The true search tune feature extends at least back to 1951 in luxury cars, although of course in those days they were AM only. FM in a car came along later than FM in home radios, except for some very special radios made available at extra cost, because the circuitry was very delicate and sensitive to environmental effects (temperature, humidity, voltage variations, vibration etc. AM technology is simple and robust, by comparison.

A General Motors subsidiary (Delco) had the patents sewed up on the search tune feature in the early days, in fact we (I worked at Philco at the time) lost our contract with Packard for radios because the lawyers told us we could not legally sell them the search tune radio we had developed. Packard switched to Delco as a radio supplier for the 1951 Search tune radio, and for all subsequent business, after buying exclusively from Philco since the very earliest factory supplied radios. (This was heavy blow for Philco, and led to the company being acquired by Ford a few years later.)

Later, in the '60s, Bendix acquired the right to build search tune radios, so some cars have Bendix built radios and some have Delco, if they are search tune. I don't know when the patents expired on this technology (I left the business in the late '50's).

Mopar didn't offer FM until sometime around 1957, as I recall, and it was a very rare option even then.

The first search tune with FM was released in GM cars, of course, and only let out to the competition after they had made the advertising splash with it.

The first FM Stereo was similarly tied up in patents, although I'm not as conversant with the facts in that matter. I am aware of Stereo in Cadillac and probably other GM cars in the early '60's - I think '64 for Cadillac (It worked, but barely, with the damn relay clicking all the time!). The delay for other luxury brands was the same deal - GM gets first crack at it because they put up the money to develop it. That's the American way, folks!

Imperial never officially listed it in the brochures (that I have seen) for 1967, but it was available in late '67. Ford was on the same schedule - I at one time had a 1967 Mustang Stereo radio - I believe that was a first for Ford.

The Stereo Multiplex receiver in the early days was quite a kludge. The bottom line is: it needed 5 seperate electronic boxes, scattered around the car including behind the rear seat, all connected with massive cables. The sound is superb, but the reception is typical early stereo - unless you live within about 25 miles of the transmitter, you spend all your time fiddling with the dial trying to keep it clearly tuned in. At least they had eliminated the clicking relay of the first units by 1967.

All you young whippersnappers (I can say that because I start into my 70th year next week!) have no idea what things were like for Jim Martin and I in the early days, trying to court our girls in the car with one hand on the damn tuning knob and the other on the steering wheel. The only solution was to park the car so you didn't need to fiddle with the controls, as I recall explaining at the time.

The modern radios, with their digital quartz lock oscillators and phase locked tuning are a revelation to those of us who struggled with this technolgy 50 years ago. They sure don't build them like they used to!


Question from Dan (1966):

Does anyone know of a good, reputable repair shop where I can send my AM/FM radio and get it overhauled so it will work as close to new as possible?? I know there are a lot of places listed in Hemmings and such magazines but was wondering if any of our IML members have first-hand experience with any place in particular?????

Reply from Dick:

If you want it to work like it did when it was new, almost any competent repair shop can do that for you - I used to do so for friends, but I retired years ago.

If you want it to work like a new one (note slight change in wording), you'll have to have it converted to modern innards, with quartz lock tuning, low noise front end, digital display, stereo audio system etc. Many of the shops you noticed in Hemming's also do this work, but it is more expensive.

What's the difference, you ask? The older technology FM radios do not have the stability to lock on a station and stay there over hill and dale, they do not reject multipath distortion (Donald Duck voices when you pass buildings or mountains), and they cannot lock on extremely weak signals such as those in areas more than 100 miles from the transmitter, and they have no "capture" technology, which allows them to lock onto one station even though a signal from another station is bleeding into the same channel. The result is very unsatisfactory operation of the FM section unless you live within 50 miles of the transmitter, and never move the car.

The difference for AM operation is smaller, but still annoying, because the older technology will drift off the station due to vibration or temperature effects, giving you distorted audio at times, and they are harder to tune accurately.


Question from Rodger (1966):

I have no parts book or FSM so I turn to the knowledge of the owners. The car of question is a 66 am/fm with reverb and rear a/c. How many speakers and just where are they ???

Replies:

From Mark:

My '66 Crown has 2 speakers, one in the dash and the rear on the drivers side rear shelf.  It is fed from the drivers 'c' column.  The reverb was located just to the right and under the liner of the trunk lock latch (under the card board)... it looks like a metal 8 track tape.

From Don:

I have a 66 Coupe with Reverb and Rear A/c. It has 2 speakers: 1 in the dash and the other in the rear package tray. The rear A/C has 2 rectangular outlets and 1 blower motor/fan assembly. This fan assembly has a bakelite spacer to accommodate the blower and speaker using the same hole in the rear package tray.


Question from Kent (1967):

I finally replaced the bad heater switch in my '67 Imperial and it and the fan now work just fine. However, it has been some time since I dismantled the dash to repair this stuff. I now have two single wires which come off the back of the radio, one green and one black and I can't find out where they hook up at. The radio is getting power but no sound. The radio worked fine before I started this project btw. The Grn wire has a Blk end and the Blk wire has a gray end. Can anybody help me please?

Replies:

From Pete:

On Mopars the radio connections to the speaker are typically green and black. On cars with a single speaker the radio wires connect directly to the speaker. On cars with multiple speakers the radio wires connnect to a harness under the dash.

From Dick:

These are the wires from the front speaker. You should find mating connectors hanging down above the radio.

From Paul:

If you have a wiring diagram, or if there is one available to down load from our club Web site, check it out. You should be able to locate the wires in the diagram, by color and connector type to see what they connect to. The diagrams look daunting but really aren't that bad, if the wording is clear and legible. I once had to go that route to reconnect the entire dash on a car that had been taken apart by someone else. It worked!

The radio may have two power leads, one for the dial light and one for the radio itself. Black often means ground, but I would never presume this without checking it out first. The speaker leads would be obvious. Usually wires coming from an accessory match up to other wires that are the same color, with a matching style opposite connector, unless they connect directly to another switch or terminal.

It would be helpful if you know that the factory radio has always been there. Sometimes after market radio installers add/change wiring. If one of them have been under there, it should be obvious by the difference in connections / colors / connector types from what is used through out the rest of the car.

From William:

To me, that sounds like the speaker wires for a normal Chrysler corporation radio from back then. Seems like they will have a gray cast plastic terminal insulator where they plug onto the radio (one male, one female?) or ganged in a common connector.

While you're under there, it might be a good time (after you recover from the contortions of the first project) to also put a new speaker in the front too. Also, it might not be a good idea to operate the radio with the leads unplugged for very long. If you have a spare speaker, you can verify if those really are speaker wires, but doing so with a Chrysler factory service manual (which will also note the color code and gauge of each wire) might be a good idea too.


Question from Rick (1967): 

I was trying to find out about the radio on my '67. I opened the door to the radio and there behind it was a Blaupunkt AM-FM typical of what would be found in a VW of the same era...and there was no rear speaker knob or power antenna switch which told me the car never had a factory radio to begin with! Any thoughts? 

Reply from Chris:

In 1967, the radio (AM, AM/FM mono, and later in the year, AM/FM stereo), power antenna, rear-seat speaker, and rear amp and reverberator were offered in numerous combinations. You could have gotten an AM radio without the power antenna, rear-seat speaker or reverb, which sounds like the way your car was equipped. Have you looked for the build sheet under the rear seat cushion (sometimes it's behind the rear seat back)? If you find it, I can decode it. Once the stereo radio became available near the end of the model year (it's officially a 1968 option, but like AutoTemp it showed up as a running change during the '67 model year), I believe the reverberator was dropped, since its purpose was to simulate stereo in a mono system by delaying the rear speaker via a simple spring (pretty clever, even if not truly effective). The brochure gave the benefit as being "for that concert-hall effect." On the window sticker for my '67, it lists the radio with AM/FM Golden Touch radio with power antenna, foot-button station changer and rear-seat speaker as one $227 option, and then the rear reverberator (which included the rear amplifier) as a separate $37 option.


Question from Roy (1967):

My radio pretty much stays on the same station, so I never noticed this problem before, but when I press on the search tune floor button the radio makes a slight pop and stops playing and the only way it comes back on is to turn the radio off and on again where it resumes with the original station. Has anyone had this experience? It acts like a little circuit breaker is popping so I wonder if the mechanism is gummed up causing it to stall, or if it might be something else.

Reply from Dick:

This is normal operation, so long as the dial is moving (searching) after you hit the search button. If it never stops, this means that the detector tube is not seeing a strong enough signal to stop the search process. There are 3 possible reasons for this, in order of likelihood:

1. The antenna is not all the way up, or is mistrimmed (see your owner's manual) or is defective. 2. You live in a fringe area, there are no stations strong enough to trip the threshold. 3. There is something wrong with the search tune hardware.

If, on the other hand, the dial does NOT move after you've hit the search bar or floor button, there is probably a build up of crud and corruption on the spring drive motor which propels the carriage across the dial. The cure for this is to take the case off and clean the bejabbers out of the search tune mechanism, also make sure the solenoid and it's trip switch that returns the carriage at the end of it's sweep across the dial is making contact and able to zap the dingus back to home position.

These mechanisms demand occasional usage, if they are left unused for weeks or months, they get balky like this, usually a good cleaning and maybe a very light touch with a clock oiler will restore proper operation.

When you cycle the on-off switch to off and back on, this resets all the logic and stops the search process, that is why the radio comes back to life when you do this. The speaker is muted when the search process is going on.


Question from Jim (1967):

Those of you with '67's ('68's too?) Do you generally DRIVE with the door over your radio open or closed? I always thought it would be very luxurious cruising across the plains with soft music playing and no obvious source, but then I figured that on a long drive you would always be monkeying with the dial trying to get a station, then again isn't there a foot switch for the travel tuner? Second, do you DISPLAY your Imperial with the door open or closed?  I guess Chrysler got the idea from TVs of the period, they often closed up so it would look like furniture. Mom always left hers open - it was always on!

Reply from Chris:

I tend to drive mine with the lid open when I'm playing the radio. Since I like to drive with all the windows down (for the airy feeling you can only get in a pillarless car), I'm frequently adjusting the volume, which can only be done from the radio knob, to compensate for ambient noises. Of course, I do make it a point to change stations at traffic lights by the foot button, with my hands obviously on the top of the steering wheel. Also, the reverberator/rear amp sounds better on the highway than around town, too, so I tend to switch it on and off.

When I show it, I close all the lids to show off the beautiful "rare walnut trim" of the "Danish Modern cabinet doors" (as the brochure says). My displays at shows explain the features rather than leaving the doors and hood open and destroying the visual impact of the car.

Yes, the 67-68 interior is very much like the most modern high-end furniture of the day, and while pushbuttons galore were the rage in the late 1950s and early 1960s (remember when stovetops even used pushbuttons to select the heat range - lo, med lo, med, med hi, hi - even though a variable knob makes so much more sense?), concealed controls on TVs, radios and kitchen appliances were the rage in the mid-to-late 1960s. A friend of mine had a stove where the entire stove top retracted behind a panel, leaving only the backlit dials to hint at the item's functional nature.

Whatever happened to such passionate detail in design? In cars today (and appliances), it's just about plastering fake-looking wood (or fake-looking fake wood) all over molded plastic interiors. Even the '99 LHS, with its neat chrome-ringed white gauges and chrome-ringed clock with wings to suggest the new/retro Chrysler logo, does this all on a sea of tan plastic.

There's no dashboard more elegant to me than the '67 Imperial, with its walnut-trimmed door armrests and control panels angling up to meet the dash panel in perfect planarity, and the way the instrument panel sweeps across the car in a glamorous line of walnut, brushed stainless steel and black glass. With the panels all closed, the shapes, materials and lines evoke a period modern architectural elegance I've never seen in another car's interior.


Question from Mark (1968):

I was driving my '68 Crown today (the 4 dr. hdtp) and I noticed that I have perfect reception on the AM side, but when I go to FM I cannot
seem to receive only 1 station at a time. I hear several stations all at once, with 1 or 2 stations all across the dial. Anyone have any ideas what's wrong?

I recently (3,4 months ago) replaced the antenna on this car.

Replies:

From Mike:

Your good reception on the AM side leads me to believe this is a problem internal to the radio, and not in the antenna or leads.

Not being an RF engineer, i can only place a conjecture as to the cause of this problem, but it sounds like your radio has a selectivity issue on the FM band. Basically, the tuning circuit isn't precise enough to dial in on one station. If the radio is original, it may be time to have a shop look at it. The tuning circuits may have drifted out of adjustment.

From John:

Adjust the antenna trimmer screw on the back of the radio. Also, FM reception is best with the antenna at about 31 inches, for AM you would extend it all the way.

From Chris:

On most cars of this vintage there is an antenna trimmer that is located somewhere on the radio near the antenna connector. This is a capacitive device that nulls the insertion loss of the antenna. Look for a hole with a small screw head looking adjustment. Set your radio's FM dial somewhere in the mid band 96-98-101 MHz and tune to a station in that range. Adjust the trimmer until you hear minimum crosstalk. This shouldn't affect the AM scale since it is tuned to a different wavelength of the antenna, and is a different modulation scheme.

From Dick:

Chris is right, mostly, with this, but in the radios I've worked on, this adjustment is only for peaking the antenna for the AM band. Just in case I've missed some, double check in your owner's manual or FSM.

I believe the antenna trimmer on our cars is usually visible when you remove the right side tuning and fader knobs, and is to be used to correct poor reception on the AM band only. The usual instructions say to tune the radio to somewhere toward the high end of the AM band, where there is no station, maximize the volume, put the antenna all the way up, then tweak the tiny screw for maximum sound level out of your speaker. Even though there's no station there, you will hear background noise, and other crud - when it is as loud as you can make it with the little screw, you've optimized the setting for your antenna and radio. There is no equivalent adjustment for the FM band, although for optimum FM reception, the antenna length should be set at 31 inches, not all the way up (although it is damn hard to tell the difference, in my experience). If your AM reception is good, there is no need to fiddle with this delicate and easily broken little trimmer capacitor.

However, none of this will do any good in the case of multiple stations coming at the same time on the FM band, this is a failure inside the radio, and the set needs to go to a competent repair shop for a major alignment with the right equipment.


Question from Mark (1968):

I found another antenna for my '68 and put it in today. Bzzzz-- it goes right up and comes right back down. So I'm happy about that; now at least I have a complete working antenna.

However, my FM reception has not improved much. AM is much better-- used to not be able to get any AM at all (the difference b/n freq. modulation vs. amplitude modulation, I guess). But on the FM side, I still get a lot of what I would call crosstalk or bleedover. You hear
one station-- but you also hear several other stations in the background. No matter where I am on the dial I'm getting several stations at once.

Reply from Dick:

Your FM receiver section is probably in need of "alignment". I take it you cannot eliminate the interfering station by careful adjustment of the tuning knob? Do you live within 50 miles or so of the stations? If so, it should work quite well.

There are quite a few radio repair outfits around that specialize in older car radios, including FM - I think you need to send it off for a complete "tune-up". This requires experience and some really sophisticated instrumentation to perform, it is not for the neophyte to fiddle with (which may be what happened to your radio, as they are normally quite stable.)


Question from Allen (1969):

It turns out my car only has the AM/FM unit -- where can I get the stereo unit with built in 8 track player? Is installation relatively easy in my 1969 Imperial or a tear apart the dash scenario?

Reply from Elijah:

You can install the AM/FM/8-track unit, but you'll have to find another instrument cluster to do so. If you look at your current radio, you'll see that the opening for it is basically a rectangle:

_________________________
|                        |
|________________________|

However, the 8-track unit uses a different instrument cluster, with an additional opening beneath the radio:

_________________________
|                        |
|___                  ___|
  o |_________________|

The little o at the left is the opening for the track-changer knob. So basically, you can do it -- but you'll have to find another radio and instrument cluster.


Question from Roger (1969):

I have a '69 Imperial.  I want to take out my AM radio and put in AM/FM radio from a ' 70 Imp.  Does the radio come out thru the front of dash or back, have any of you folks done this before sure would like some tips.

Reply from Elijah:

The radio comes out the back of the dash.

1. Remove single screw attaching A/C spot cooler duct from beneath steering column (long black plastic tube that goes from far left of dash over to the center).

2. Remove the four screws from the Vent lever panel beneath the steering column. Lower panel to floor (be careful - the plastic will break easily).

3. Remove four screws attaching center ash tray and remove ash tray (you'll have to disconnect one wire for the lighter and one for the ash tray light).

4. Remove nut from attaching bracket at back of radio (bracket goes from radio to bottom of the dash).

5. Disconnect antenna and radio wiring.

6. Remove two screws from bottom of radio (you'll find access openings beneath the dash).

7. Carefully lower the radio down and out of the dash.

8. Lather. Rinse. Repeat.

9. Install new radio and put it all back together.

10. Take a muscle relaxant to allow your back to return to its previous uncontorted position.


Question from Jonathan (1970's):

I was just looking at some listings of radio options for Chryslers from the mid-70's and turned up something interesting. Those of us into Fuselage Imperials are probably aware of the floor-mounted tape cassette player/recorders that were available -- for the roving executive who wanted to play his newest tapes, and dictate as he drove. The Dictaphone on wheels for the 1970's. Anyhow, I found that in '74, Chrysler introduced a dash-mounted cassette player. It came as a combination AM/FM stereo radio with cassette (with Dolby). What I'm wondering is does this radio for '74-'79 fit the slot for the '69-'73 generation of Imperials? This would be a great way to get a cassette player in an Imperial. Not only would it be in the dash, but it would still be a vintage Mopar radio/cassette and it would match the interior pretty well. Plus you wouldn't have to pay the outrageous prices people are asking for the floor mounted cassette/recorders. Ok, it's the only factory tape RECORDER I've ever seen listed by an auto-maker, but is it really worth $500.00? Try to keep editorials to a minimum on this. We've vented over this topic before, I think. I'd just like to know if the '74-'79 Mopar radio/cassettes will fit the radio slots in the '69-'73 Imperials? Thanks in advance.

Replies:

From Frank:

I don't think they would fit properly as the '74 and up dash is completely different.   It probably depends on how flush you want it. 

From Jack:

In a word, no. They are very different in the face plate, and mounting system. The dash on a 69-73 has a single din sized opening, and the 74-98 Mopar is a 1 1/2 din opening.  If you look at the 8 tracks of the fuselage years, there was an opening just under the radio in the dash for the 8 track slot, which required a unique dash panel, (or a cut out?)  I think there is a subtle curvature in the dash as well, which would make the flat front units all the more difficult to adapt.  Now, all the radio openings, and most of the radios from 74 till about 98 will fit each other. but that's another story.....


Question from Jay (1973):

This weekend I decided to do something about the radio in Silent Bob, my '73 LeBaron 4DHT. It has not worked since the distributor failed spectacularly in May. I found the oddest problem I could imagine . . .

When the distributor went out with a bang, the radio quit, along with the clock and everything else on fuse #8. A few fuses later my son and I figured out that the radio was the problem, though the clock still doesn't work. The turn signals and backup lights do, which was my main concern.

Saturday I decided I had been without tunes long enough and pulled the radio. Take out the a/c duct, remove the driver's side ash tray, then two screws, the ground strap, and the red power wire and the purple/gray/brown output connection, not too bad. Hook the power connection back up and use a test lead to put ground to the case, turned the switch, ground wire heated up and began to smoke, so the problem is definitely in the radio. Took the radio chassis (AM/FM/8TK) to the bench and popped the top and bottom covers to look inside and see if there is anything wrong that I can _see_, like a burnt resistor or melted insulation. Hmm, a sticker with a 510 area code that indicates this radio was benched sometime in '99.

What's this? The red (power) wire enters the back of the chassis through a rubber grommet and is SOLDERED TO THE SIDE OF THE CHASSIS? No wonder the test lead heated up and smoked! But it looks like a factory solder, and there is a gray or blue (can't remember) wire soldered to the same location. How in heck did it work with the power lead soldered to ground?

My questions:

1) Is that the way this thing is supposed to be wired? (Don't think so . . .)

2) So how is it supposed to be wired?

3) If I disconnect the power-to-ground connection, will that put the radio back in service?

4) Why doesn't the clock work, since it's not even on the same circuit, according to the FSM?

5) Should I just chuck the factory radio (don't really want to) and put in an AM/FM/CD (really would like to have CD capability)?

Replies:

From Arran:

I think that you have found your problem. I can't speak for a '73 Imperial but most radios are wired so that they are grounded through the metal box to the frame of the car, even with a positive ground cars. The power wire connecting to the box of course leaves you with a dead short and a blown fuse. The power wire should be connected to the circuit board inside but the question is where? If I had a circuit diagram or the radio in front of me I could probably tell you.

From Kerry:

The red wire goes into the chassis in the same hole as the rest of the wiring harness. I bet if you take the case off, you will find where someone pulled it out and then, thinking it was a ground, just stuck it on the case.

From Jack:

I just went through a fun project with my '73.

the stock am/fm/stereo was nonfunctional, so I found a replacement on Ebay, (under $10) Turns out this is a unit that could interface with the optional cassette player/recorder on the hump. With some help from the FSM I could decode the 7pin din 'dongle' on the back of the radio to wire in a DPDT switch, and a mini stereo cable which I ran around and under things to between the front seats. I use an Ipod player, but you could just as well plug it into a portable CD or trunk mount a changer if it interfaces with RCA plugs..

I've replaced the stock speakers with some bargains I found on www.partsexpress.com (under $25 all the way around) and it sounds really quite good. (considering the 30 yr old head unit) and it's all totally stock looking. I'm thinking about adding line level converters and external amps, but, that's a ways down the list. 


Question from Zack (1974):

I tried taking the radio out from the front, but it wouldn't come out. Do I have to remove the dash pad? If so, how hard is it, and how long should it take?

Reply from James:

You only have to remove the metal part of the dash on top (where the defrost vents are). When you get this off you'll see a metal grounding bracket screwed to the dash, and bolted to the radio. You can undo the bolt on the radio (7/16" I think) which you can't actually see while you're working on, or just take out the screw on top. Sometimes it's hard to pull the stereo out with the grounding bracket still attached though. Like other people have said, check all antenna connections before screwing with the radio itself. Have you lost both AM and FM reception? I managed to destroy the antenna connector on mine at one point and then only FM worked (weakly), with a new connector everything was jolly good again.


Question from Alan (1976):

I drive a 1976 NYB, with a couple of minor problems.

The original radio is the Wonderbar analog, with no tape or CD. The reception in town is acceptable, but drive 20 miles out of town and you have no radio, along with no tape player. I have the foot switch on the floor to activate the Wonderbar station seek. I have pulled it out for a CD radio, but you know how it is with collectibles. It's great to have the original working machinery.

Any ideas for rebuilding or replacing the original? Some approximate prices would also be appreciated.

Reply from Arran:

Sometimes weak reception can be caused by a bad connection between the radio and the antenna. There should be a plug that goes into the back of the radio and some sort of large spade connector attaching the wire to the bottom of the antenna. Look for corrosion at this connector, a loose connection between it and the antenna, or a broken wire. Check this out first before you break out your wallet and have the radio worked on.


Question from Bruce (1978):

The mighty '78 NYB has a nifty AM/FM/CB radio. Right now, only the FM seems to work, but the previous owner drove it across country and used the CB not too long ago. He mentioned a "coil" that attached to the top of the antenna that is now missing. Has anyone heard of this and what it does?

Reply from Brad:

Just a tip about CB radios. If there is no antenna attached to the radio and you key the mic, you WILL blow the output transistors and they will need to be replaces (good luck finding those). Just trying to help those with the cool CB radios who might not know this. This is the most common way a CB gets destroyed.


Question from Greg (cassette player):

Wasn't there a late sixties or early seventies option of a cassette player/recorder that attached to the floor?

Reply from Elijah:

That's right -- the cassette option was offered in '71, and I think in '70, but I'm not sure.

Anyway, it was a cassette deck mounted in a pod-like affair that was affixed to the transmission hump just under the dash. Not only could you play cassettes through your five-speaker high-fidelity mulitplex stereo system, but you could also record things from the radio AND make personal recordings through the microphone which was included with the system -- pretty nifty, huh?

For those of you who have '71 through '73 Imperials with the non-8track multiplex radio, look under the dash at the back of the radio sometime -- you'll see a thick black cable about two inches long with a large plug. If you remove the cap from this plug, you'll see that this is actually a round five-pin connector -- this was where the cassette unit plugged in, so if you ever find one, you can easily add it to your car!

Don't lose that cap, though -- the radio itself won't work without it, unless you have a cassette deck to plug in!

From Larry:

It sounds like the same thing used in the other Mopar's of that vintage.  I have one, from a "73 Charger SE, that was never installed. It is kind of tan in color, though the base plate cover is green.


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