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  #16  
Old 12-22-2015, 02:26 PM
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The short one is 7" the long one is 8 3/4".

I cleaned the vhf tuner and replaced that uhf dial light in the '75. I didn't notice this before, but the '75 uses the VRT power supply and the '74 doesn't.
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  #17  
Old 12-23-2015, 02:53 PM
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Quote:
Originally Posted by Adam View Post
The short one is 7" the long one is 8 3/4".

I cleaned the vhf tuner and replaced that uhf dial light in the '75. I didn't notice this before, but the '75 uses the VRT power supply and the '74 doesn't.
My spare antenna rods are 8.5" and 13.5".
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  #18  
Old 12-23-2015, 03:28 PM
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I might have some other rods in a box of parts, I'll look later tonight.

More pics of the '75. I cleaned up the chassis a little bit. I had straightened that piece of metal that goes in the front about 90%, tried to improve it, and wound up screwing it up worse (it's very thin). Eventually, what I wound up doing is getting some of that stick on fake chrome they put on cars now, and cutting a piece to fit. It looks ok. I'm also trying to repair that spot (you can see it in primer) on the CRT mask, where it looked like someone dropped something on it that corroded the plastic. This seems to be a pretty low hour set, judging by the CRT. But it also seems as if it was stored in a damp basement underneath somebody's junk and chemicals. (I'm just repairing that one bad spot, there's other places where the cabinet is melted or scratched and it's not so noticeable. And the cabinet, particularly the back, was very dirty.)
Attached Images
File Type: jpg 75zen100.jpg (80.9 KB, 23 views)
File Type: jpg 75zen101.jpg (66.7 KB, 18 views)
File Type: jpg 75zen103.jpg (53.8 KB, 27 views)
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Last edited by Adam; 12-23-2015 at 04:29 PM.
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  #19  
Old 12-23-2015, 05:35 PM
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The ball antennas are a PIA usually. Just rods with screws
easier. If you do just a rod use a grinding wheel to smooth
out the old rod stub & it will come right out. The phosphor -
bronze spring will stay in place. Better yet get a 1-127 from
someone. Wickid common antenna for 70's Zeniths, B&W or color.

73 Zeno
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  #20  
Old 12-23-2015, 07:54 PM
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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.
Attached Images
File Type: jpg 111.jpg (22.6 KB, 16 views)
File Type: jpg 2.jpg (13.3 KB, 14 views)
File Type: jpg 3.jpg (13.6 KB, 13 views)
File Type: jpg 4.jpg (10.6 KB, 8 views)
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Last edited by Adam; 12-23-2015 at 08:08 PM.
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  #21  
Old 12-24-2015, 01:37 AM
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Quote:
Originally Posted by Adam View Post
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?
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  #22  
Old 12-24-2015, 10:42 PM
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Probably, if I had the equipment to do that.

I worked some more on the 74. I cleaned the contacts in the tuner, cleaned the dirt and dust off the chassis. Put the timer back together for now. And now I just have to glue some cracks together on the bottom of the cabinet.
Attached Images
File Type: jpg 74zen100.jpg (51.3 KB, 21 views)
File Type: jpg 74zen101.jpg (62.5 KB, 27 views)
File Type: jpg 74zen102.jpg (52.6 KB, 21 views)
File Type: jpg 74zen103.jpg (39.7 KB, 22 views)
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  #23  
Old 01-07-2016, 01:39 AM
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I picked up a bunch of zenith antennas, but while I have several sets of two of the same length, they're all too long and get in the way of the power transformer. So for now, I'll have to live with uneven antennas on the 75. I put it back together, and now it's sitting on top of my '57 SC200 console. I put the '74 on the stand I got with the '75.
Attached Images
File Type: jpg 1975 zenith.jpg (74.9 KB, 18 views)
File Type: jpg 74zenith.jpg (33.6 KB, 18 views)
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  #24  
Old 01-07-2016, 10:27 AM
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I have access to 3D printing, if you could use the part.
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  #25  
Old 01-11-2016, 12:07 AM
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Thanks for thinking about this. But I don't really know anything about 3D printing: How the original part would be scanned or the computer program corresponding to the image of the part would then be modified to enlarge those worn down edges… Does anyone really know if such a thing is possible, if so how I could get the part scanned?
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Last edited by Adam; 01-11-2016 at 12:30 AM.
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  #26  
Old 04-02-2017, 12:25 AM
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I came across an image of an advertisement for the white 74. Zenith called it "the odessa." Pic below...
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File Type: jpg 74zenith.jpg (23.8 KB, 22 views)
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