1950s or '60s vintage Zenith TVs, Need some info

[Tom9589]

One other important connector on the tuner is the IF output. It will be a shielded cable with most likely an RCA style plug on the end of it. So you have four connections on the tuner: IF output, filament, B+ and AGC. If the Sams is new enough, all of the connections will appear in the upper lefthand corner of the schematic.

The motorized tuner mechanism is completely separate from these tuner connections.

[vortalexfan]

Originally Posted by Tom9589

One other important connector on the tuner is the IF output. It will be a shielded cable with most likely an RCA style plug on the end of it. So you have four connections on the tuner: IF output, filament, B+ and AGC. If the Sams is new enough, all of the connections will appear in the upper lefthand corner of the schematic.

The motorized tuner mechanism is completely separate from these tuner connections.

The IF Connection is was an obvious connection (the only connector that has an RCA Style connector), same for the B+ Connector the only connectors that aren't as obvious are the AGC and the Filiment connectors, and the Sam's copy I have doesn't list the connections anywhere on the Photofact.

[vortalexfan]

I looked over the schematic again and it did show the connections but it wasn't a style of wiring diagram I was expecting, and it turns out I had the AGC and the Filiment wires switched. I was trying to hook the twin-leads back up to the antenna terminals on the back of the TV and one of the spade connectors broke off the twin-lead connector for the UHF connector.

[vortalexfan]

OK, so I hooked the tuner up properly and I'm still not getting anything out of the tuner yet, no lights or anything, so I wonder if the tuner is just dead on this TV? Although when I tune through the channels with the power tuner, I get a little disturbance on the screen like the tuner is trying to pick something up, but the screen just goes blank.

[Electronic M]

Originally Posted by vortalexfan

OK, so I hooked the tuner up properly and I'm still not getting anything out of the tuner yet, no lights or anything, so I wonder if the tuner is just dead on this TV? Although when I tune through the channels with the power tuner, I get a little disturbance on the screen like the tuner is trying to pick something up, but the screen just goes blank.

Have you cleaned the tuner channel strip contacts yet? About a month ago when I was getting the 1964 TV chassis on my Zenith Chancellor going the contacts were so dirty it wouldn't tune anything for a while, and then barely would if you wiggled the knob just right...A thorough clean that took the contacts from black to shiny got it to where it works the first time every time I tune it.

The easiest way to tell which terminal is for heater is to trace the dial light lead...that lead will have continuity to the correct terminal.
Test your dial light bulb too...If it's burned out it's not a good visual aid to tell you if you're heater lead is hooked up right.

[vortalexfan]

Originally Posted by Electronic M

Have you cleaned the tuner channel strip contacts yet? About a month ago when I was getting the 1964 TV chassis on my Zenith Chancellor going the contacts were so dirty it wouldn't tune anything for a while, and then barely would if you wiggled the knob just right...A thorough clean that took the contacts from black to shiny got it to where it works the first time every time I tune it.

The easiest way to tell which terminal is for heater is to trace the dial light lead...that lead will have continuity to the correct terminal.
Test your dial light bulb too...If it's burned out it's not a good visual aid to tell you if you're heater lead is hooked up right.

I'll take a look into cleaning the tuner contacts tomorrow. It would make sense that the tuner strip contacts would need cleaning, seeing as everything else in this TV was filthy and needed cleaning.

[vortalexfan]

OK, so I took the tuner assembly apart and looked it over and it was actually pretty clean inside not much in the way of corrosion or dirt etc. which is interesting considering the rest of the TV was absolutely filthy inside.

but now I have a new problem, the volume control pot for the TV has a broken terminal, the terminal that the ground wires from the audio coaxials broke off when I was trying to remove it from the volume pot so that I could work on the tuner assembly and also the connector for the ground wires that go to the volume control pot broke off the ground wire leads and I'm not sure if I can source some new connectors like the original ones or not.

Does anyone have a spare volume control/power switch assembly for one of these old Zenith TVs laying around in their parts stash that they could send me? I'm asking because I'm not sure where to look to try and find a NOS replacement power switch/volume control pot for this TV.

[vortalexfan]

OK So I've started digging into the Zenith "Bugeye" TV and the Electrolytic caps listed for this TV are all oddball values that I can't seem to find modern equivalents to without having to go way above or below the orginal capacitor's rated value. One of the capacitors I'm referring to is the main filter capacitor which is a 140 MFD 150 VDC capacitor which the closest standard stocked value capacitor at AES is a 100 MFD 160 VDC electrolytic capacitor, and over at Mouser they had a 140 MFD 150 VDC capacitor but it was almost $30 just for that one capacitor!

So what did you guys do to replace the original electrolytics in this TV?

[old_tv_nut]

Here's a search at Digikey
https://www.digikey.com/en/products/...BKiUrjgYDPFxIA

which turns up for example
https://www.digikey.com/en/products/...2C151S/1245954
150 uF, 160 V, $1.98 in quantity of 1
By the way, the +/- 20% tolerance is way better than the original, which was probably +100/-20%

Of course, you should do a much more detailed search to find the closest reasonably priced to fit.

[Yamamaya42]

Originally Posted by vortalexfan

OK So I've started digging into the Zenith "Bugeye" TV and the Electrolytic caps listed for this TV are all oddball values that I can't seem to find modern equivalents to without having to go way above or below the orginal capacitor's rated value. One of the capacitors I'm referring to is the main filter capacitor which is a 140 MFD 150 VDC capacitor which the closest standard stocked value capacitor at AES is a 100 MFD 160 VDC electrolytic capacitor, and over at Mouser they had a 140 MFD 150 VDC capacitor but it was almost $30 just for that one capacitor!

So what did you guys do to replace the original electrolytics in this TV?

for filter caps, you NEVER have to be exact. for a 140 MFD 150 VDC cap, for example, i would use something like, 667-EEU-ED2C151 , but that is just me.

[dtvmcdonald]

I would use a 150 or 180 uF 200 volt cap rated at 105C from Nichicon
or United Chemi-con from Mouser or Digikey (radial leads). At AES a value of 150, 180, or 220 uF at 200 to 450 volts will do as well. These days capacitors are voltage rated
a bit differently than in olden times and its a bit better to go higher in voltage rating if available (i.e. it seems OK to use a 450 or 500 volt cap if the old one was).

As a filter cap it is non-critical value ... in the old days they were usually rated at -50+100% value tolerance!

[vortalexfan]

OK, thanks, I was wondering about that but I wasn't sure, which is why I asked.

Also it turns out I wasted $15 (actually $30 if you count the fact that I ordered the wrong photofact the first time around over at Sam's because for some weird reason the Sam's Index didn't show the 16Y20U Chassis in it anywhere) because it turns out I actually had an original physical copy of the Sam's for the Zenith "Bugeye" TV in my Sam's Photofact stash.

[zeno]

If one of the caps is mounted on an insulator its the doubler cap.
You must use a 105 deg or it will puke out mung & fail in a short time.
Its OK to sub in for testing but the 105 needs to go in eventually.
Most new 'lytics come in the following.
1mfd, 2.2, 3.3, 4.7, 10, 22, 33, 47, 100mfd etc
Sub a little over the mfd if need be. The new caps wont be cans.
Pick up some terminal strips to mount them & be sure to cut out
the old cans, not leaving them in circuit.

73 Zeno
LFOD !

[init4fun]

Originally Posted by zeno

.... it will puke out mung...

Yep, seen "The Exorcist" back in the 1970's, , , Now there's a great mental image for a leaking capacitor for ya

[vortalexfan]

Originally Posted by zeno

If one of the caps is mounted on an insulator its the doubler cap.
You must use a 105 deg or it will puke out mung & fail in a short time.
Its OK to sub in for testing but the 105 needs to go in eventually.
Most new 'lytics come in the following.
1mfd, 2.2, 3.3, 4.7, 10, 22, 33, 47, 100mfd etc
Sub a little over the mfd if need be. The new caps wont be cans.
Pick up some terminal strips to mount them & be sure to cut out
the old cans, not leaving them in circuit.

73 Zeno
LFOD !

Yes there's one single value can mounted on an insulator in the TV its a 140 MFD 150 VDC capacitor.

The rest of the capacitors are mounted straight to the chassis. So what is it about the voltage doubler circuit that it needs to have a high temp. rated capacitor in that spot?