75 Zenith 19" b/w

[Adam]

I've looked for both the antennas that actually fit this and those universal replacement rods that screw in with no luck. (I'd buy a big lot of either if I could find any.) Antennas seem to be among the hardest parts to find, I've had an easier time finding flys, yokes, and even CRTs than antennas. But I just bought a lot of Zenith antennas off of ebay tonight, none that actually fit this set, but enough that I can take them apart like I did before and at least get two of the same length.

This is how the auto-off on the 74 works:

Looking at the first picture, the motor turns the black screw gear which gears it way down, which then turns the white gear. There are two switches (circled) the top one is the power to the tv, the bottom one is to the motor. They both go off when pressed in.

Looking at the 2nd pic, the wider piece circled pushes in the motor switch, the other one the tv switch. That way to the right of the position where both switches are off, the tv and the motor is on and the timer is counting down, to the left the motor switch is still pushed off but the tv switch is not pushed in and on again, allowing for the tv to be on and the timer not running.

Looking at the 3rd pic, you can see that groove that the piece that pushes the switches off uses to ride on the big white screw gear. The problem is that the ridges of that groove are worn down to the point where the white screw gear turns and doesn't move that black piece that pushes the switches off.

The 4th pic shows the way the piece with the groove attaches to the piece that pushes the switches off with that spring. You push it in so the groove isn't in contact with the white screw gear when you set the position of the timer so it can slide freely. My guess is that it got broken by someone trying to set the timer without pushing it in first.

Unless I can get a new one of those pieces with the worn out edges on the groove that rides on the white screw gear (the thing circled in the 3rd pic), I don't think I can fix this. I can't think of any way I can build up any material on those edges and keep it simultaneously thin enough to fit in the white gear, but also strong enough not to easily break off.

[Electronic M]

Originally Posted by Adam

I've looked for both the antennas that actually fit this and those universal replacement rods that screw in with no luck. (I'd buy a big lot of either if I could find any.) Antennas seem to be among the hardest parts to find, I've had an easier time finding flys, yokes, and even CRTs than antennas. But I just bought a lot of Zenith antennas off of ebay tonight, none that actually fit this set, but enough that I can take them apart like I did before and at least get two of the same length.

This is how the auto-off on the 74 works:

Looking at the first picture, the motor turns the black screw gear which gears it way down, which then turns the white gear. There are two switches (circled) the top one is the power to the tv, the bottom one is to the motor. They both go off when pressed in.

Looking at the 2nd pic, the wider piece circled pushes in the motor switch, the other one the tv switch. That way to the right of the position where both switches are off, the tv and the motor is on and the timer is counting down, to the left the motor switch is still pushed off but the tv switch is not pushed in and on again, allowing for the tv to be on and the timer not running.

Looking at the 3rd pic, you can see that groove that the piece that pushes the switches off uses to ride on the big white screw gear. The problem is that the ridges of that groove are worn down to the point where the white screw gear turns and doesn't move that black piece that pushes the switches off.

The 4th pic shows the way the piece with the groove attaches to the piece that pushes the switches off with that spring. You push it in so the groove isn't in contact with the white screw gear when you set the position of the timer so it can slide freely. My guess is that it got broken by someone trying to set the timer without pushing it in first.

Unless I can get a new one of those pieces with the worn out edges on the groove that rides on the white screw gear (the thing circled in the 3rd pic), I don't think I can fix this. I can't think of any way I can build up any material on those edges and keep it simultaneously thin enough to fit in the white gear, but also strong enough not to easily break off.

I wonder if it could be 3D scanned the ridges enlarged in a CAD program, and a better one then 3D printed?