Quote:
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.
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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