1950 Zenith 12" Porthole Restoration

This 1950 Zenith 12" Porthole was the second set I acquired. It's model G2346R and is called the Graemer. It sold for $339.95 new in 1950. That was big money in those days. Adjusted for inflation in equivelent 2011 dollars it would cost you $3342.00.

I purchased the set through a listing on Craigslist, from a person in Poynette, Wisconsin who had acquired it at an estate sale. The set was in relatively good cosmetic condition, with only a few scratches here and there. But the varnish on the doors was in very poor condition. The 12UP4 picture tube was defective and so that was the first item on my list of items to obtain.

The 12UP4 is a tube that is difficult to obtain. It is a metal body 12" tube, used for the most part on Zenith Porthole sets and a few others. It took several months to locate one from another collector that lives in the Chicago area. With a good 12UP4 in hand I was now able to start the restoration.

As usual the first task in the chassis restoration is to make a list of all the capacitors that will be needed, and order them. I do this by going down the list of capacitors in the Sams Photofact schematic.

While waiting for the capacitors to arrive, I started on the cabinet restoration. The fine quality cabinet is made from mahogany solids and quality mahogany veneer plywoods. I first removed the doors and stripped off all of the old varnish. I think the set may have been exposed to direct sunlight for a long time because the varnish on the front doors was very flaky and dry looking on the outside, but the inside of the doors was perfect. As is the case with many sets, the top of the cabinet was also in need of stripping and refinishing. After stripping the varnish I mixed stain until I had a shade that looked like a good match, and then stained the front side of the doors and the cabinet top. When it was dry I sealed the surface with two coats of shellac. Following the shellac, I sprayed several coats of clear automotive acrylic lacquer. I also gave a light sanding to the main body of the cabinet and then sprayed on two coats of clear lacquer to match the lacquer on the newly refinished doors.

The round bezel around the picture tube was very dirty but after a good cleaning, a nice finish was revealed underneath. I also sprayed a coat of clear lacquer over this bezel to give it a nice new finish. Often speaker grill cloth is in very poor condition but because this is a full door set, the speaker grill cloth was protected by the closed doors during it's long life. As a result the speaker grill cloth was in very pristine condition and did not even require any cleaning.

The brass control door below the screen, had some of the lacquer coating worn off and there was tarnish in those areas. I stripped the remaining clear lacquer off of the control door and polished the solid brass door with buffing compound and a cotton buffing wheel. Then I sprayed 2 coats of clear lacquer over the newly polished brass control door to prevent future tarnish. You will notice a small slide switch below the Zenith emblem on the control door. One of the features on the Zenith Portholes was a feature that allowed you to view a "magnified" image on the round tube. The slide switch selected a normal picture that had a blank area at the top and bottom of the screen, or if you prefered you could select a "magnified" picture which streched the verticle height and filled the entire screen top to bottom. This was similar to the "Opera Glass" feature that was offered on Stromberg Carlson sets of the same era, except that on the Zenith sets, only the verticle height was streched. On the Stromberg Carlson sets the "Opera Glass" feature streched both the verticle and the horizontal which prevented the picture from being distorted.

The brass trim rings behind the channel and volume knobs were also tarnished. I removed them and used the same method as was used on the brass control door to restore them to a bright luster. Back when this set was made, manufacturers were still using quality materials like the solid brass on these parts. As a result the old parts can be re-polished and lacquered and will look as good as the day they left the factory in 1950

When the replacement capacitors arrived, I removed all of the old bumble bee style bakelite capacitors one at a time, and replaced them with the new ones. These black bakelite capacitors are refered to as Bumble Bee's by TV restorers, because the black body with the color stripes remind us of bumble bees. These bumble bee type capacitors are just old wax paper types inside of a molded bakelite body. They are every bit as un-reliable as a common wax paper capacitor so I always replace all of them.

I tested all the tubes and replaced any weak ones with strong tubes from my inventory of vacuum tubes. I plugged the chassis into my variac and slowly brought the chassis up to full line voltage. After adjusting the ion trap I got a nice bright full raster over the entire screen. I hooked up a pair of rabbit ears, and with some adjustment of the various controls I was rewarded with a very nice picture. The quality of the picture really amazed me. It was sharp, clear, and in focus.

I put the finished chassis in the newly refinished cabinet, bolted it in place. The old rubber line cord was in poor condition so I replaced it.


Then I installed the back of the set. then I sat down and watch some old episides of Amos and Andy. It was just like 1950 all over again.


Here is a front view of the finished restoration with the doors open.