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

[vortalexfan]

Originally Posted by Electronic M

Got HV? Got correct CRT grid-cathode voltage? Are the fuses all good?

Tubes being good doesn't mean squat if there's significant issues in other components. And something tiny and easy to change can prevent raster from existing.

No, there doesn't seem to be HV which is kind of confusing because the HV rectifier is in really good shape and the Flyback is in really shape (no melted wax etc.)

The picture tube is glowing in the back and the Picture tube looks to be low hours as the cathode material inside is a shiny silvery color yet and not a dark gray color like a high hours tube would be.

I could pull the chassis and check some of the components underneath but in all honesty except for a bunch of dirt inside the chassis (its literally dirt, not dust, like it may of been in a garage or barn for many years) the set seems to be a low hour set.

from what I could see of the underside of the chassis from the topside I did see one Bumblebee cap (no idea of the value on it though as I couldn't make out the color code on it.)

As for the Bugeye TV I replaced all of the Deflection tubes on the TV and tried to temporarily hook up an 8 ohm bookshelf speaker to the output transformer, and turned on the TV and all I got out of the TV was a loud hum from the speaker which at first I thought maybe it was related to bad filter caps but then when I turned down the volume the hum went away.

Is it possible for an impedance mismatch in a tube audio circuit to cause a hum that can be adjusted by the volume control?

EDIT: Definitely failed filter caps, and I checked the date code on the picture tube on this TV and it does seem to be the original picture tube (or else a NOS tube because the picture tube is a GE branded Picture tube with a Date Code of 58-17 or 17th Week of 1958 which is right around the time period this TV was made, also I think the Selenium Rectifiers are going bad because when I powered on the TV I smelled a burning surfury smell coming from the TV that seemed to be coming from the Selenium Rectifiers.

So how do you remove the chassis out of the Zenith Bugeye TV? I'm asking because I don't see any obvious ways to get the Chassis out (marked screws or anything), also when I was trying to take the socket off the back of the CRT on the Zenith Bugeye TV I accidentally pulled the picture tube's base off (the plastic part with the pins on it that the socket plugs into) thankfully the wires are still intact but trying to feed the wires back into the pins in the base for resoldering is going to be tricky, also trying to figure out how to reglue the base back onto the CRT so it doesn't break off again.

[vortalexfan]

OK, so I downloaded the Sam's Photofact for the big Zenith, which is a 15L22U Chassis, and according to the Sam's my TV was supposed to be Remote Controled Model (they don't give any other arrangements of that particular chassis) and the fact that my TV clearly has a spot in it for a remote control receiver sub-chassis, but there's nothing there clearly shows that more than likely this was indeed a remote controlled model originally but then possibly the original owners of the TV were having issues with the remote control functions so they decided to have the repairman remove the remote control receiver subchassis from the TV so they didn't have to worry about it anymore so then they just operated it "manually" (using the push-button in the front of the TV) and just called it good enough.

Also according to the Sam's that auto/ manual switch on the back of the TV was indeed a remote control receiver defeat switch just like I said it was, and the fact that the hole was actually punched out on the back cover of my TV rather than just being a "blank" (unpunched) hole is another reason why I suspect this TV originally was a remote controlled set.

[dieseljeep]

Originally Posted by vortalexfan

OK, so I downloaded the Sam's Photofact for the big Zenith, which is a 15L22U Chassis, and according to the Sam's my TV was supposed to be Remote Controled Model (they don't give any other arrangements of that particular chassis) and the fact that my TV clearly has a spot in it for a remote control receiver sub-chassis, but there's nothing there clearly shows that more than likely this was indeed a remote controlled model originally but then possibly the original owners of the TV were having issues with the remote control functions so they decided to have the repairman remove the remote control receiver subchassis from the TV so they didn't have to worry about it anymore so then they just operated it "manually" (using the push-button in the front of the TV) and just called it good enough.

Also according to the Sam's that auto/ manual switch on the back of the TV was indeed a remote control receiver defeat switch just like I said it was, and the fact that the hole was actually punched out on the back cover of my TV rather than just being a "blank" (unpunched) hole is another reason why I suspect this TV originally was a remote controlled set.

AFAIK, the remote unit has to be in there to operate the motor driven tuner.
I has relays and other parts for the motor drive. The metal cabinet sets generally used the same back for all the models of the same size. It's more cost effective.

[vortalexfan]

Originally Posted by dieseljeep

AFAIK, the remote unit has to be in there to operate the motor driven tuner.
I has relays and other parts for the motor drive. The metal cabinet sets generally used the same back for all the models of the same size. It's more cost effective.

Hmm, I'm surprised, because RCA and Philco for their remote control TVs (and non-remote control sets) used different backs for example I had a 19" Philco Townhouse TV from 1962 (same time period as this TV) and they were available as remote control and non-remote control models, and the non-remote control models had the remote control defeat switch cutouts molded into the back cover but they weren't cutout (plastic rear covers) same goes for my 17" RCA TV (also from abt. 1962) which also came with or without the option for a remote, and the back cover on my RCA has the remote control defeat switch hole molded into the back cover but its not cut out the units that originally came with a remote had the hole cutout for it, and the units that didn't didn't have the hole cutout for it. Now of course that might be the difference between a plastic cover vs. a metal cover but that still shouldn't make a difference I wouldn't think.

Anyways Why would a remote control model vs. a non-remote model make a difference in whether or not the front push-button would work or not, in a motorized tuner set? Shouldn't the Motorized tuning still work on these TVs even if the remote was out of the picture on a remote controlled unit?

[Notimetolooz]

Originally Posted by vortalexfan

The picture tube is glowing in the back and the Picture tube looks to be low hours as the cathode material inside is a shiny silvery color yet and not a dark gray color like a high hours tube would be.


As for the Bugeye TV I replaced all of the Deflection tubes on the TV and tried to temporarily hook up an 8 ohm bookshelf speaker to the output transformer, and turned on the TV and all I got out of the TV was a loud hum from the speaker which at first I thought maybe it was related to bad filter caps but then when I turned down the volume the hum went away.

Is it possible for an impedance mismatch in a tube audio circuit to cause a hum that can be adjusted by the volume control?

EDIT: Definitely failed filter caps, and I checked the date code on the picture tube on this TV and it does seem to be the original picture tube (or else a NOS tube because the picture tube is a GE branded Picture tube with a Date Code of 58-17 or 17th Week of 1958 which is right around the time period this TV was made, also I think the Selenium Rectifiers are going bad because when I powered on the TV I smelled a burning surfury smell coming from the TV that seemed to be coming from the Selenium Rectifiers.

So how do you remove the chassis out of the Zenith Bugeye TV? I'm asking because I don't see any obvious ways to get the Chassis out (marked screws or anything), also when I was trying to take the socket off the back of the CRT on the Zenith Bugeye TV I accidentally pulled the picture tube's base off (the plastic part with the pins on it that the socket plugs into) thankfully the wires are still intact but trying to feed the wires back into the pins in the base for resoldering is going to be tricky, also trying to figure out how to reglue the base back onto the CRT so it doesn't break off again.

First off lets get your terminology correct, the silver coating in a tube is the "getter". It is a deposit of a metal that will grab any trace of oxygen in the tube. Sometimes it is silver, sometimes it is grey, it depends on how quickly it was deposited. When the getter starts to turn white it means there is too much gas in the tube for it to handle. The cathode is a very small cylindrical metal "can" shape with a small spot of white cathode material on the end. It is all but completely impossible to see from the outside.
An impedance mis-match would not cause hum.
Pulling the CRT base off is a rookie mistake. I'm sure you know how hard it is to find good CRTs today. Always hold the base with one hand and the socket in the other when separating the two. I think that at least one person on this forum has posted about re-connecting the base. I'm sure Phil Nelson of Phil's Old Radios had to repair one that was already loose. Generally you remove most of the old cement, clean the glass and base well, solder on extension wires to the one still on the tube, and remove all the solder inside the base pins. With the longer wires it is much easier to feed them into the socket. The original cement used a mixture of things like water glass, marble dust, shellac, etc. which is hard to find. Many people use "electronic safe" silicon sealant, (it does not smell like vinegar).
In fact Phil has a restoration article about a similar set.
https://www.antiqueradio.org/zen28.htm

[vortalexfan]

Originally Posted by Notimetolooz

First off lets get your terminology correct, the silver coating in a tube is the "getter". It is a deposit of a metal that will grab any trace of oxygen in the tube. Sometimes it is silver, sometimes it is grey, it depends on how quickly it was deposited. When the getter starts to turn white it means there is too much gas in the tube for it to handle. The cathode is a very small cylindrical metal "can" shape with a small spot of white cathode material on the end. It is all but completely impossible to see from the outside.
An impedance mis-match would not cause hum.
Pulling the CRT base off is a rookie mistake. I'm sure you know how hard it is to find good CRTs today. Always hold the base with one hand and the socket in the other when separating the two. I think that at least one person on this forum has posted about re-connecting the base. I'm sure Phil Nelson of Phil's Old Radios had to repair one that was already loose. Generally you remove most of the old cement, clean the glass and base well, solder on extension wires to the one still on the tube, and remove all the solder inside the base pins. With the longer wires it is much easier to feed them into the socket. The original cement used a mixture of things like water glass, marble dust, shellac, etc. which is hard to find. Many people use "electronic safe" silicon sealant, (it does not smell like vinegar).
In fact Phil has a restoration article about a similar set.
https://www.antiqueradio.org/zen28.htm

Ok, I apologize for using the wrong terms for the parts inside the Picture tube, I was going by what I was loosely remembering Shango066 say about how he could tell if a picture tube was low or high hours which I guess I remembered the terms he used wrong.

As for the picture tube repair there's a lots of wire left so I should be able to fish the wire through (the wire leads didn't break off they just more or less slid cleanly through the holes in the tube base pins because there apparently wasn't much solder on the tube base pins.

[dieseljeep]

Originally Posted by vortalexfan

No, there doesn't seem to be HV which is kind of confusing because the HV rectifier is in really good shape and the Flyback is in really shape (no melted wax etc.)

The picture tube is glowing in the back and the Picture tube looks to be low hours as the cathode material inside is a shiny silvery color yet and not a dark gray color like a high hours tube would be.

I could pull the chassis and check some of the components underneath but in all honesty except for a bunch of dirt inside the chassis (its literally dirt, not dust, like it may of been in a garage or barn for many years) the set seems to be a low hour set.

from what I could see of the underside of the chassis from the topside I did see one Bumblebee cap (no idea of the value on it though as I couldn't make out the color code on it.)

As for the Bugeye TV I replaced all of the Deflection tubes on the TV and tried to temporarily hook up an 8 ohm bookshelf speaker to the output transformer, and turned on the TV and all I got out of the TV was a loud hum from the speaker which at first I thought maybe it was related to bad filter caps but then when I turned down the volume the hum went away.

Is it possible for an impedance mismatch in a tube audio circuit to cause a hum that can be adjusted by the volume control?

EDIT: Definitely failed filter caps, and I checked the date code on the picture tube on this TV and it does seem to be the original picture tube (or else a NOS tube because the picture tube is a GE branded Picture tube with a Date Code of 58-17 or 17th Week of 1958 which is right around the time period this TV was made, also I think the Selenium Rectifiers are going bad because when I powered on the TV I smelled a burning surfury smell coming from the TV that seemed to be coming from the Selenium Rectifiers.

So how do you remove the chassis out of the Zenith Bugeye TV? I'm asking because I don't see any obvious ways to get the Chassis out (marked screws or anything), also when I was trying to take the socket off the back of the CRT on the Zenith Bugeye TV I accidentally pulled the picture tube's base off (the plastic part with the pins on it that the socket plugs into) thankfully the wires are still intact but trying to feed the wires back into the pins in the base for resoldering is going to be tricky, also trying to figure out how to reglue the base back onto the CRT so it doesn't break off again.

Did you figure out how to work on the bugeye? The cabinet slides off the chassis by removing the top knobs and the two screws on the top and bottom rear edge of the cabinet wraparound. Probably, easier to lay set on it's face and it slides off.

[vortalexfan]

Originally Posted by dieseljeep

Did you figure out how to work on the bugeye? The cabinet slides off the chassis by removing the top knobs and the two screws on the top and bottom rear edge of the cabinet wraparound. Probably, easier to lay set on it's face and it slides off.

Yes I did, I finally got it apart, and it looks pretty straight forward and simple to recap and also it has a very small amount of paper caps to replace as the majority of the caps in the unit are ceramic disc and mylar type.