Zenith H2447R 19" Porthole TV

[Crist Rigott]

Originally Posted by jr_tech

Looking good!

I like the fact that you label the parts... I actually used one of your underchassis pictures when working on a set (7inch Philco?) . It was much clearer than the Sams photo, and in color, which helps, as well! Thanks!

jr

Now that's a great idea! You're welcome.

[Crist Rigott]

I finished applying the Super Corona Dope to the fly back tonight. After the last coat, I baked it for several more hours. Here is what I'm going with:

[Crist Rigott]

I thought I'd restore the power supply first. Then the main chassis.

The PS chassis is pretty green from the CAD plating.



I scrubbed it off using a mixture of 50/50 CLR and water. I used a green Scotchbrite pad I get at the Home Depot. I then used Q-tips to swab out the underneath part of the chassis. All was rinsed with Isopropyl alcohol and then dried.

When flipping it over one time, it slipped out of my hand and broke the E-Cap phenolic insulator. After removing the E-Cap (C2) I removed and replaced the insulator mount using some 4-40 screws, lock washers, and nuts. All better now. While I was removing the rivets on the mount I also removed the Candohm (R62) resistor. I then bolted on a 3.5K 25W chassis mount resistor. I'll never have to worry about that going bad! I also used some heat sink compound between the resistor and chassis.



I then noticed that in 2 places a grounding lug was riveted to the chassis. I cleaned both up with a small wire brush and applied some flux to the area. I used my 150W soldering iron to solder both of those ground lugs to the chassis. Only one is shown.

[Crist Rigott]

I then got to work on re-stuffing the E-Cap (C2). I'll use my usual method of cutting off the base right at the bottom of the can, clean it all out, true up the parting surfaces of both the base and the can. I enlarged the hole in the middle of the base to 5/32. Then I epoxy a 1 inch tall piece of PVC pipe to the base. Making sure there is no epoxy on the outside which will interfere with a good seam where the base and can meet. Tomorrow I'll add the replacement E-Caps.

[wa2ise]

Sometimes I misread the thread titles, here I first misread "porthole" as "portable". Wonder if Zenith ever made a portable porthole.
Like those GE locomotive like portables, except with the entire round CRT exposed.

[Electronic M]

Originally Posted by wa2ise

Sometimes I misread the thread titles, here I first misread "porthole" as "portable". Wonder if Zenith ever made a portable porthole.
Like those GE locomotive like portables, except with the entire round CRT exposed.

There was a 12" table set IIRC 1950 model year in a leatherette cabinet...Not sure if they had the stones to add a handle and call it portable.

IIRC MacDonald had the engineers adapt a table model porthole chassis into the back seat of his limo so he could watch TV on the go....Some electronics mag of the day had a write up on it. I bet he let them do the article as a way to put out feelers to see if there would be a car-tv market.

[Crist Rigott]

I started on the main chassis and the E-Caps first. I removed C1 and C3. When removing them, I broke off some of the twisty mounting tabs. This is usually the case. Once is a great while, I'm able to remove a can without breaking them off. These were really twisted!

I'll go into detail on how I re-stuff a E-Cap. Both of these caps are 4 sectioned caps. A while ago I won an auction that had like 25 E-Caps that were 4 sections with the sole purpose of using them as "donor" bases.

Here are the 2 caps and their donors.



I cut the originals as close to the base as I can with my band saw. I use a piece of 1/32 plywood as a shim to prop up the can because the base is larger in diameter. As I cut with the band saw, sometimes I'll rotate the cap some just to help keep the cut straight.



Here are the results of cutting the originals. All I'm interested in are the "cans". The bases are no good to me.
After removing the cardboard covers using my heat gun, I then cut the bases off the donor caps. This iime close but not so close to the base as with the originals. Here are the results:





Notice how much fuller the original cans are compared to the donors. Here is a picture of the original cans and the cleaned up donor bases. I clean up the bases using a brass brush and then drill a 5/32 hole in the middle. These holes were offset slightly to avoid drilling through the terminal symbols. I'll clean out the cans using a heat gun to remove the guts, and some steel wire brushes, acetone, paper towels, and Q-Tips to clean the cans.



The donor bases are about 1/8 inch taller than the originals. Not a problem on this chassis.



Next thing to do is make up some sleeves from 1 inch PVC pipe I got at Home Depot. I forgot the exact size but maybe it's 1 1/2 inch pipe. It is the thin walled stuff. The first thing I do is true up the end using my disc sander and 90 degree guide. When truing it up, I rotate the pipe about 1/2 to 3/4 turns.



I then mark the trued up end with an arrow. This end will be glued down against the base.



I then use my 1 inch wide ruler to make a mark 1 inch up from the trued end. I go all around the pipe.





I then cut off the pipe on the line just made. I then clean up the cut end with the disc sander. I then repeat the whole process for the other sleeve starting with truing up one end.
Once I have the sleeves cut out I then de-burr them using my hobby knife and #11 blade, and some 80 grit sandpaper.



I then use 15 minute epoxy and apply the epoxy on the trued up end being careful not to get any epoxy on the outside of the sleeve. Then the sleeve is inserted down onto the base. I then clean off any and all epoxy that has gotten onto the outside of the sleeve especially down near the base. Any epoxy here will prevent a good seam when the can is put into place.

[WISCOJIM]

Originally Posted by Electronic M

IIRC MacDonald had the engineers adapt a table model porthole chassis into the back seat of his limo so he could watch TV on the go....Some electronics mag of the day had a write up on it. I bet he let them do the article as a way to put out feelers to see if there would be a car-tv market.

Different MacDonald?

https://books.google.com/books?id=NN...r%20tv&f=false

.

[Electronic M]

Originally Posted by WISCOJIM

Different MacDonald?

https://books.google.com/books?id=NN...r%20tv&f=false

.

That is the article I remember.