1949 Zenith Porthole Restoration

[ChrisW6ATV]

Nice progress. Those sets are very cool.

[Radiotronman]

Ok,

I changed the remaining three electrolytic canned capacitors and the power resistors and I was rewarded with a one inch line on the screen! So at least we know the flyback isn't gone. Now to figure out why I'm getting insufficient height. If I turn brightness up or down, the raster will disappear.....

[IsthmusTV]

Nice work! Have you tried carefully adjusting the ion trap?

You've come a long way and you're getting really close!

-Clark

[Radiotronman]

It didn't have an ion trap on the crt when I got it. I can try one from another set and see if there's any change. Thanks!

[bandersen]

If it doesn't have one and you see something on the screen, it doesn't need one. Probably an aluminized CRT like a 10FP4.

[Radiotronman]

After swapping out a couple of tubes I was rewarded with a picture and audio! It only has 4000volts at the second anode, but definty progress. Now I have to figure out my insufficient high voltage priblem.

[damen]

Originally Posted by Radiotronman

After swapping out a couple of tubes I was rewarded with a picture and audio! It only has 4000volts at the second anode, but definty progress. Now I have to figure out my insufficient high voltage priblem.

Your set is looking great and what a nice job you did on the cabinet replacing the veneer. Does it have a Rouland picture tube?

[Radiotronman]

Thanks Damen.

My set actually has a GE 12kp4 tube in it. Still working on where my high voltage is being pulled down. I love the looks of your set, especially with that brass trim in the grill cloth area.

Scott

[IsthmusTV]

Originally Posted by bandersen

If it doesn't have one and you see something on the screen, it doesn't need one. Probably an aluminized CRT like a 10FP4.

Hmm. If it has a 12LP4 as stated in an earlier post, that would normally require a double field ion trap. Probably a rebuild with a straight gun in it.

Looks like your getting close!

-Clark

[damen]

Originally Posted by Radiotronman

Thanks Damen.

My set actually has a GE 12kp4 tube in it. Still working on where my high voltage is being pulled down. I love the looks of your set, especially with that brass trim in the grill cloth area.

Scott

Thanks!! Hope you get the one like it from your friend. Be cool to have both. I know a lot of things could cause voltage to be low good luck on that.

[Radiotronman]

I'm hoping to make the missing slats and side molding for the cabinet tomorrow morning. These 49 zeniths are the hardest to find. The switch to light up the clear prisms are so cool to me.

[Radiotronman]

Worked on the case a little more this weekend, since the weather was nice. I finished making the slats and the top side molding, with vent cutouts.

[Radiotronman]

This is the top side molding.

[damen]

Wow!! That looks great

[Radiotronman]

So I still only have 4000v at the second anode and can't find any obvious signs of why. Voltages at the horizontal output, damper and picture tube all test pretty close to the values listed in the schemstic.