[Sean]

Hi Harlan,

I believe the 3-pin socket is for an external antenna.

The auto antenna style jack (I think this is a Motorola style but I may be wrong) is the phono input. The RCA jack is for the output from the phonograph. Your radio should have the Philco Beam-of-Light phonograph in it. This phonograph used a lamp that reflected light off of a mirror attached to the stylus. A photo-cell received this light and converted it into the electrical signal to be amplified by the radio chassis. The lamp was powered from the oscillator running around 500KHz or so since 60Hz would be picked up by the photo-cell and would be heard in the speaker. There is also an audio transformer in a black case mounted inside the top of the cabinet to the left of the chassis when viewed from the rear. The cable that plugs into the RCA jack goes into this transformer and the cable with the auto antenna plug comes out of the transformer. I have attached a photo of the rear of a 41-608 I restored a couple of years ago. Oh, and the octal socket on the rear of the chassis is for the optional HR-1 home recording unit that could be installed onto the phonograph.

For the speaker I would recommend Hank Hank Brazeal in Alabama. I have had him do a couple of speakers and he does excellent work.