Mid 50's Zenith Set

[init4fun]

Originally Posted by Notimetolooz

I think this set doesn't use a power transformer, that means that the chassis may be "live" (connected to one side of the power line). This is an added danger if you touch the chassis while it is plugged in. The best way to protect yourself (and sometimes test equipment) is to use an isolation transformer, but for one set it probably isn't worth the expense....

With all due respect , OF COURSE it's worth the expense !

To Hell with the TV or any test equipment , trinkets can be replaced , people can't , and there have been lots of folks done in by good ol 110 !

An Isolation transformer is a must for any hot chassis set , it's the electronics hobby's Jockstrap

[Notimetolooz]

Originally Posted by init4fun

With all due respect , OF COURSE it's worth the expense !

To Hell with the TV or any test equipment , trinkets can be replaced , people can't , and there have been lots of folks done in by good ol 110 !

An Isolation transformer is a must for any hot chassis set , it's the electronics hobby's Jockstrap

I wasn't saying he should do anything risky, rather use a "work around".
That work around would be to use probe clips on the test equipment so that he doesn't have to touch the set while it is powered up. Of course he would only be able to use un-grounded test equipment like a battery powered meter.

[Notimetolooz]

I just noticed that the set in Phil's article uses chassis 16T20, where as your's is a 16Y20 chassis. Probably very similar, but you should try to get the correct schematic.

[Jeffhs]

Originally Posted by Notimetolooz

I wasn't saying he should do anything risky, rather use a "work around".
That work around would be to use probe clips on the test equipment so that he doesn't have to touch the set while it is powered up. Of course he would only be able to use un-grounded test equipment like a battery powered meter.

I wouldn't try to repair a hot-chassis TV, radio or any other device while it was plugged in and turned on, due to the shock hazard; I'd use an isolation transformer, as one other poster suggested. Using insulated probes isn't enough. The set's chassis will still be "hot" with the line voltage, and will still be a shock hazard and possibly a fire hazard as well, particularly if any metal object (probe tip, etc.) shorts to the chassis. This will effectively short the AC line directly to ground since, in transformerless televisions and radios, one side of the line is connected directly to the chassis. The house fuse or the equipment's own line fuse may blow, but I wouldn't count on it. The safest way to work on so-called AC-DC radios and transformerless televisions is to unplug the AC power cord (and discharge any filter capacitors) before doing anything in, on or under the chassis.

[Notimetolooz]

I think that an important word in my earlier post was missed. I was talking about using CLIPS, insulated alligator clips or the like, to attach the test equipment to the set so that the set doesn't have to be touched during a measurement.
https://www.digikey.com/product-deta...1173-ND/573996
Set unplugged.
Attach clips. Hands off set.
Plug in set.
Note measurement.
Unplug set.
Repeat as necessary.
It is not fast or convenient but it will work.
Anyway the original poster may be satisfied with just replacing the capacitors. Although I would also replace the selenium rectifiers with silicon ones. I'm not sure, but it seems like this is his first venture into working on vintage equipment. It is bad enough to tell someone, that thinks he got a great deal on a TV set, that he will have to buy new parts and test equipment, costing several times what he paid, to get it to work right. I don't want to discourage someone by insisting on another $ 50 or more piece of equipment unless he will be working on more TVs.