Monday, November 25, 2013

In The Beginning

The radio arrived on Saturday 23rd, 2013. First things first. The radio is a AC-2905 Delco radio with the "Studebaker" script on the dial face. This radio is a six tube superhetrodyne receiver covering the AM band. Here is a link to the SAMS Photofact on it:

AC-2905 .PDF

The first thing in getting it going was to remove the vibrator and see if the tube filament light up. After resoldering the power wire, filaments lite!

The next step is to see if the vibrator would run. It did run but not very loud and there was very little voltage on the secondary of the power transformer. Next, pull the rectifier to see if it was shorting the transformer. No such luck, still low voltage. So next was to open up the vibrator and see if it is Tango Uniform:

I used a grinder to remove the lip on the vibrator:

Here is the guts of the vibrator with the sound deadening rubber puller back. Can't really see the contacts but believe me, they were burnt.

So next I fiddled with the contacts to get some form of usable operation so testing could move forward. I did get the vibrator to function for a little while and got high voltage on the output of the power transformer. I then plugged in the rectifier tube but no output from it. I cut the load off the filter capacitor and did get 100 VDC on the capacitors. Not sure if it was low because of the vibrator, bad rectifier, of leaky filter capacitors.

So my next steps will to be to order a solid state vibrator and replace the filter capacitors. What I will probably do is to hog out the existing filter capacitor can and slip into the can modern capacitors to keep the original external appearance.

 Did not find a single thread of the dial cord. Based on the nibbling through out the radio, I suspect that the dial cord was tastey...

 Back of the face plate. Looks like the echelon is crimped into the pot metal face plate. With care it can be removed, cleaned up, and painted.
 Faceplate is bent up a bit but it can be straightened and may not be the prettiest..

Found a three tube mud hornet nest just below the rectifier socket (not shown here)

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