Atwater Kent Model 70

This weekend's Radio Projects were an Atlas 210x HF transceiver and an Atwater Kent model 70 console radio.

This particular Atwater Kent model 70 radio is very special. My Great Grandparents purchased it new in 1930 from Hale's Department store in Downtown San Jose.  The store was located on the corner of First and San Carlos streets which is now the San Jose Silicon Valley Chamber of Commerce.  Here is what the area looked like at the time.

I picked it up from my grandfather so I could restore it as a family heirloom. It's been stored in his basement for decades. Other than having some scuffs and some finish damage from a leaking can of tomato paste, the radio was in pretty good shape.

Here's a picture of the Atwater Kent Type L" chassis. It''s a TRF design as you can tell from the multiple air variable capacitors.

Instructions mounted in the cabinet.

Upon first inspection, I found that the 80 rectifier tube had been swapped with one of the 45 audio output tubes.  I also noticed that the power transformer was not original.  I wasn't sure if the tube swap was intentional or not.  These tubes look very similar so someone might have made a mistake.

Normally, I'd trace wires before doing anything with the radio but Grandpa had insisted the radio was working when it was put away. I decided to bring it up slowly on the Variac.  Unfortunately, the radio  did not show any signs of life.  I needed to know if the tube swap was intentional or not so  I opened up the case and checked underneath.

The tube swap was certainly not intentional.  The transformer leads went straight to the socket that was intended for the #80 rectifier tube. Was some ancestor playing with the radio perhaps?  I put the tube in the correct socket, but the radio was still dead.

That transformer looks like it has been leaking tar.  Was this from the original transformer or the replacement?  The bottom of the radio had a paper cover and had tar goop on it.  Hopefully the transformer was OK.

A little more inspection revealed a 2 amp fuse on the power input that had blown. Problem #2 was found. 

Fortunately, I keep fuses in stock.  Though, this fuse is also readily available on Amazon.  If you need an assortment, they also have large assortments for sale cheaply so you can build up your stock as well.

This brought the radio to life!

There was still more work to do.  The tuning dial was slipping.  This was due to a rubber bushing that was supposed to be stuck tight to the tuning shaft.  It was pretty loose after sitting on there for 82 years. 

I could have gone on a hunt for a replacement bushing. However, since it was rubber, I simply used rubber cement to glue it to the inner bushing.  This took care of the tuning for now. 

I then reassembled the radio and waxed the case with carnuba floor wax.

The radio has dials for tuning, tone, and volume. Here's a quick demo while the radio was playing.

Unfortunately, there's still going to be some more work to do on this radio. After playing it for a while, the acrid smell of burnt tar started to fill the room.  Ugh!! Guess that transformer is suspect after all.