Zenith 24h20 Porthole

[leadlike]

FINALLY had some time tonight and rewound the width coil. From the closeup picture earlier in the thread, you can see that it is two spools. When I pulled the coil, the top spool crumbled in my hands. The center shaft on the spool burned up, exposing bare coil wires to the adjustable inductor, shorting the windings to ground, causing the 5u4 to flash over.

As the spool was gone, I could only make note of the winding direction of the coil, and strip it. The spool ends were still intact, if a little cooked (no conductive carbon, thought). So I made a properly sized cardboard tube for a new center shaft, and began winding magnet wire onto it (#36, seemed pretty close to the original) by hand. Once I got a good base laid down, I chucked the coil into my drill, and spun the rest on. The whole operation took about an hour and a half.

I hooked it up, and the set powered up. The coil didn't heat up, like the old one did, so I hooked up a video source and the crt, and was rewarded with a decent picture. Vertical hold is still twitchy, but it you leave it alone, it stays put. Sound is extremely poor. I suspect low bandwidth getting through, but adjusting the various sound and tuning controls still produces the same result with fuzzy highs and lows.

BTW, the old width coil measured 15 ohms, and the newly wound one checks out at 15.6 ohms! Not bad!

Otherwise, the picture looks decent, and the set is much easier to operate. I suspect that the bad width coil was heating up and loading things down a bit. Will take some measurements next.