1963-1964 AM-FM Delco Chrysler Radios
by Carl Bilter

The 1963-64 Chrysler AM-FM radios were produced by Delco, and were the first factory radios offered by Chrysler with the FM band. The FM band was monaural on these radios. FM multiplex stereo broadcasting was introduced in 1961, but stereo FM was not offered on Chrysler radios until later in the 1960's as car radio receiver technology advanced.

The modern FM band from 88MHz-108MHz was established in the USA around 1946. Radio manufacturers began including the band on their higher end sets, but most early circuit designs had less sensitivity and selectivity than modern sets. Relatively few stations occupied the band in the early years (compared to the crowded dials of today). While FM offered the potential of superior sound quality compared to AM, with a broadcast frequency response typically 20Hz-15,000Hz along with static-free reception, the signal strength would vary dramatically depending on the receiver antenna location, height, and distance from the transmitter. Consequently, given the limitations of the receiver technology of the day, the small size of the car radio chassis, and the rapidly changing signal strength in the mobile environment, it was impractical to offer the FM band in car radios.

By the early 1960's, through the use of transistors and more advanced circuit designs, it became viable to offer the FM band on car radios. Effective with production starting in January, 1963, this AM-FM radio became available as the premium radio offering on the Chrysler line.

In both 1963 and 1964 the radio was only available with the front fender mounted manual antenna. Why not offer it with the optional power antenna? After all, the radio was available on the Imperial in 1964 with a power antenna. Actually, it had nothing to do with manual vs. power, it had to do with the location of the antenna. On the Chrysler, the optional power antenna was located on the rear fender and therefore required a long antenna lead-in cable. On the AM band, an antenna trimmer on the radio had to be adjusted by the dealer to compensate for the long cable, which was part of the tuned input circuit. The AM-FM set included a trimmer located on the underside of the radio to perform this adjustment for the AM band, but there was no such adjustment for the FM band. I guess the concern was that the long lead-in cable might adversely affect FM reception to the point that customer complaints would result. I'm not convinced it's a big deal, as my experience with bench testing the radio is that the FM sensitivity is excellent and is sufficient to offset potential problems with the long cable. However, such an installation with a power antenna in a 300J or 300K would be incorrect for concours judging.

That said, for those considering a radio upgrade to their 300J or 300K by simply installing one of these AM-FM sets in the bezel opening that is currently occupied by their Bendix AM 5 button or 7 button set, think again! The Delco AM-FM radio has a physically smaller front fascia than the Bendix sets do, and the radio knobs are spaced closer together. A special dash bezel was produced for these radios, and you will need that part in order to install the radio. Here is a photo of the special bezel:

This particular example was removed from a New Yorker Salon, where this radio, A/C and Auto-Pilot were standard equipment. Auto-Pilot was not available on the 300J or 300K with the Firepower 390 ram engine, and A/C was optional of course, and so you'll need a bezel with suitable cutouts for the options on your car. They are fairly rare.

Note that there are not separate cutouts for the radio knobs. That is because these radios use a special chrome plated escutcheon that is mounted on top of the aluminum dash bezel but under the radio knobs. Here is a photo of that item:

These radios featured excellent reception on both bands. The AM band performance is comparable to the Bendix AM radios offered the same year, although subjectively I think the sound quality is a bit better on the Bendix sets. The FM band reception was close to state of the art for the day, but the FM fidelity was really no better than the AM band and nowhere near that of high end home hi-fi or stereo sets of the period. Do not expect hi-fi FM sound from these radios. We'll discuss that below. These radios were similar in style to their GM “wonderbar” counterparts sans the search-tune capability. The circuit, however, was unique to the Chrysler model. You might read on the internet that one should NEVER use a speaker less than 8 ohms with these Delco sets, and you'll see that on reputable radio repair and restoration sites. That is INCORRECT. They are talking about the GM radios, which used special 10 ohm speakers. The Chrysler versions of these sets were designed to be used with the 4 ohm Mopar speakers used on the AM only radios. Both the 1963 and 1964 versions appear cosmetically identical from the front as installed in the car, but the physical chassis and circuits are different for each year.

We will now examine each model year offering separately. Please refer to our introductory page about radios for general information and servicing tips here: https://chrysler300club.com/tech/radio/1.html

1963
The AM-FM radio was model 333, available as sales code 366 with front speaker only and sales code 367 with both front and rear speakers. Only 10 300Js (2.5%) were equipped with this radio. It is VERY rare. Most sets that survive were pulled from New Yorker Salons, where it was standard equipment. A mid-year offering, only 593 New Yorker Salons were built for 1963 and few survive.
The set was 100% solid-sate (no tubes) featuring 9 PNP transistors. The output transistor was located on the back of the chassis and was surrounded by huge heat sinks for cooling. Power output is not specified but seems more than adequate. The FM circuit featured an RF amp and four IF stages are utilized to achieve excellent reception. Being a mono receiver, the IF filters are probably narrow in order to achieve excellent channel selectivity. However, high frequency response is compromised in doing so. The audio circuit is shared with the AM band and also rolls off high frequencies. After all, the same lousy Mopar “Deluxe” 6”x9” speakers used on the Bendix AM sets were also used on these radios.
The 1963 version uses 11 electrolytic capacitors, all of which are probably bad if original. Three are located in a large aluminum can on the board and two others are in smaller cans. Contained in the large can is a 4uf e-cap rated at 11.5 V AC (not DC). That one can be replaced with a conventional film cap rather than an e-cap; I use a Panasonic 4.7uf film cap. One e-cap is located inside the tuner but a new one can be paralleled in outside the tuner by studying the schematic and physical circuit layout. For both model years it is essential to obtain a Sam's Photofact manual and maybe the Delco manual as well if service is required. Each year is different.

Here is a photo of the front of the 1963 radio. This one has incorrect tone and fader controls.
The controls should be the same as the Bendix AM sets.


Here is a photo of the back of the 1963 radio showing the output transistor and heat sinks:

1964
The 1964 version was model 351, available as sales code 363 with front speaker only (MSRP $157.00) and sales code 365 with both front and rear speakers (MSRP $174.30). We don't have all the 300K records compiled yet, but it appears that approximately 15% of the 300Ks were ordered with this radio.
As in 1963 the set was 100% solid-sate (no tubes) but was upgraded to 10 PNP transistors with the addition of a second AF (audio frequency) amp. The output transistor was again located on the back of the chassis and was surrounded by huge heat sinks for cooling. An FM RF amp and four FM IF stages were used as in 1963.
The 1964 version uses 9 electrolytic capacitors, again, all of which are probably bad if original. Three are located in the large aluminum can on the board but the others are individual. The 3 e-caps in the large can are the same as 1963. As in 1963, one e-cap is located inside the tuner but a new one can be paralleled in outside the tuner by studying the schematic and physical circuit layout.

Here is a photo of the front a 1964 radio (with correct knobs). It looks the same as the 1963 version:

The 1964 chassis had some rearranging of the external physical components. Here is a photo of the back of the chassis. Note the positioning of the jumper in the rear speaker socket which is required when only a front speaker is connected.

For both years, the radio internals are crowded and challenging to work on. If you are a DIY car guy, but a radio novice, this would not be the easiest set to learn on. But I like a good challenge and decided to work on one of these as my second car radio project ever attempted. The unit is a 1964 set removed from a parts car that hadn't been powered up in perhaps 40 or 50 years.

Here is what the radio looks like inside from the top:

The complete underside of the circuit board is accessible. The tuner is enclosed on the upper right and is best left undisturbed. Removing the circuit board can be risky because it is very old. Unsoldering all the connections can result in broken traces. However, it is possible to parallel in new e-caps for 8 of the 9 total from above. You absolutely need a circuit trace diagram to do this, and the Delco service manual has one. The Sam's Photofact has photos of the physical layout with components keyed to the schematic. The results will look a bit messy, but will functionally work. The 10^th e-cap is easily accessible from the bottom of the chassis.

Here is a photo of the internals from the bottom of the set:

That aforementioned 10^th e-cap can seen in the far upper right of the photo (it is mounted vertically) next to the variable resistor for the output transistor bias adjustment. On the middle far right is the large e-cap can, soldered to the circuit board. Do not try to remove it; just parallel in new caps from the other side.

I powered up the set prior to servicing to see if it worked. It did not play. Shocker! However, it did power on and the output transistor heated up. Being 100% solid-state, these radios are “instant on” and they produce a noticeable “thump” in the speaker when turned on. So the good news was that the audio output worked.

I installed new caps in parallel with the 3 in the can, and tried again. The radio worked! Sort of. But barely. Then I installed the remaining new e-caps one-by-one checking the radio each time (to ensure each new connection was good). At some point the radio began working – quite well – but not consistently. It required all 9 e-caps to be replaced, and at that point the radio works great. It is back from the dead.

Often, all that is required is cleaning the controls and switches with Deoxit and replacing the electrolytic capacitors to regain full functionality. The transistors do not typically go bad (but they can). As a DIY car guy, you too can do this!