Discovery Of A Treasure
My friends Dick and Mary Klug are avid estate sale patrons. About once a year they call me about a TV that they have seen at an estate sale. This time they found me a real GEM. The set is a 1951 RCA model 9T79, also known as the Northampton. In 1951 this set was a top of the line model with a delux cabinet and a 19 inch screen (the largest screen RCA offered in 1951). This is a photo of the set as I first saw it in the living room at the estate sale.

Based upon a service tag I found inside the set, the owners originally lived at 1933 W. Nash in Milwaukee, which is literally 3 blocks away from the appartment that I lived in when I was 4 years old. At some point, the owners of this set moved to West Allis near 76th and Oaklahoma where the set was discovered at the estate sale. This is a photo of the service tag found inside the set, dated January 28, 1958.

Cabinet Restoration
When I first laid my eyes on the set at the estate sale, the top of the set was in very nice condition. Unfortunately I needed to store the set on my mothers screen porch for a couple years until I could get around to restoring it. During the time it was on the back porch, the top of the set was exposed to some intense sunlight which caused some damage to the varnish on the top of the set. The varnish had become sun bleached. It was an easy thing to remedy. I took some 200 grit wet emery and wet sanded the top of the set which removed most of the faded varnish. The wet slurry from the sanding was a yucky mustard color and had the smell of old varnish. After the wet sanding was completed, I wiped the top with an automotive grade pre-cleaner designed to remove all traces of wax. Then I sprayed two liberal coats of pre-catalyzed lacquer, and after the lacquer was cured, the top looked as good as new. Notice the interesting feature of seperate doors. Two doors for the TV Screen and two doors below that cover the 12" speaker.

Electronic Restoration
My first task, as always, was to test the 19AP4 picture tube.  Much to my surprise, the picture tube tested LIKE NEW!  Stuck on the back of the high voltage cage was a sticker which stated that the set had a “FACTORY OVERHALL” buy the RCA Service Company. Because of the pristine condition of this set, and because of the RCA Service Company sticker, I have to assume that the set was probably under service contract with RCA Service Company, and at some point near the end of its daily use, the set had the picture tube replaced. This is a photo of the "Factory Overhall" sticker.

The fact that I had a great picture tube to work with and a pristine cabinet, gave me the incentive to restore this set to operating condition again.  I put the set on a variac and gradually powered the set up. At around 85 volts I could hear the horizontal oscillator singing and at that point I cranked up the brightness control.  I had a nice bright horizontal line, indicating the high voltage section was working but the vertical section had a problem.  I did a bunch of tube swapping, but it was to no avail.  The vertical section had a definite problem which would need me to pull the chassis and put it on the bench. Over the next couple days I completely I replaced all the capacitors.

I hooked the set up to a CRT substitute box to do some live trouble shooting.  As it turned out, the vertical height control had some tin whiskers, which was preventing the vertical section from operating.  I put my oscilloscope on the horizontal section and re-adjusted the horizontal oscillator waveform and frequency, and then the horizontal section was able to lock up.  At that point I got a picture on the test crt.

The tuner was problematic.  I don't like RCA wafer switch style tuners.  They have so many switch contacts that can oxidize and cause intermittent video as you switch channels.  So I gave the tuner switches a liberal bath of De-Oxit tuner cleaner.  Cleaning the tuner contacts fixed the intermittent issue, however the local oscillators were a bit off of center.  It was causing the fine tuning to be out of range in both directions as you changed channels.  Some more adjusting of the local oscillators and I was able to tune multiple channels properly.

I installed the chassis back into the cabinet and hooked everything up.  After a bit more adjusting of the vertical and horizontal linearity, and height and width, focus, and centering I was presented with a fairly nice picture.  Electronically the set was ready to go. Here are a few screen shots of the fully restored and operational RCA Northampton.