Zenith 12" Porthole

[Radiotronman]

Just picked up this zenith porthole, model G2745-OX. It has the metal coned 12" 12UP4. It uses chassis 27F20. It looks lik the schematic glued in the lower inside part of the cabinet, has a second schematic glued on top of another one. I guess zenith made changes. I'm trying to determine if it's a 1948 or 1949 set. It came with its knobs, I just left them on s bag on top for now. After I finish my 1951 philco 16", I will move in to this set next. I love the flip open doors and prismatic viewing dials on the 1949 portholes and have been searching for a console. It's wierd this model is not listed in the sand index, only the chassis? The CRT tests weak, but I think after a little cooking it will be viewable. This seller also had a extra set of knobs that I need for my zenith 29t926 I've been working on!

[Electronic M]

Chassis # = way to tell electronic guts apart, Model # = way to tell the different wood boxes they often put the same guts in as other boxes apart. It was common to not bother to list all the wood box identifiers in the schematic indexes.

The chassis number is always the first number to search on all, but the more unique sets.

[Paul Knaack]

Whoa, nice looking set. That cabinet doesn't look like it even needs much attention Plus you got the knobs to finish your 29t926. Can't beat that. You are a porthole magnet.

[oldtvsandtoy]

Ok I hate to jump someones post but does anyone have a good 12UP4 to sell? Also could use the left side knob door Thanks and sorry again

[decojoe67]

A classic '40's porthole TV! Nice find. I'm going to say it's a '48 with it's prismatic panels, but so many models spilled over a year after their original production date.

[ohohyodafarted]

Originally Posted by oldtvsandtoy

Ok I hate to jump someones post but does anyone have a good 12UP4 to sell? Also could use the left side knob door Thanks and sorry again

PM sent

[tvdude1]

Just sold one last week to a member here for 50.00

[Radiotronman]

Restoration is under way on this porthole. I've replaced a couple open sand coated resistors and as many capacitors as I had replacements on hand for. This set has 7 multi section electrolytics, so I have got to order plenty of those too. I'm amazed at how many bumblebee caps and white colored caps are cracked open on this set. Many 1meg+ resistors are lower in value, instead of the normal drift above value. I'll finish correcting the horizontal rolling on my 1951 Philco 16" while I'm waiting on parts.

[dtvmcdonald]

Mr. Muntz would have had a stroke looking at the bottom of a set that late,
looking like that. Far too many parts!

[Radiotronman]

I agree. Luckily Ive restored a few portholes already, as these are not for the faint at heart. The schematic shows the 16", which is a little different than my 12" set. Many cap values are different and in different places. A definite tip is to oil the fine tuning mechanism before using. They get sluggish over the years and won't turn, breaking the dial string. The dial string goes through the center of the chassis and is very difficult to get to and restring.

[Radiotronman]

After replacing all of the electrolytics and most of the bumblebee caps replaced. I fired it up and I have a raster! More work to do...

[Radiotronman]

Finally got video but having difficulty getting the horizontal from rolling every few minutes. Adjusting the horizontal phase trimmer and horizontal frequency trimmer will get in locked in, but then it'll roll again. Must be a resistor in the sync circuit somewhere out of tolerance.

[Radiotronman]

Ok, calling this one done! Very good picture and sound on this set.

[Kevin Kuehn]

It looks really nice! So were you able to solve the rolling issue?

[Samuel1981]

That was fast. Video! How did you handle the rolling issue?