Zenith roundie alert near Salem, OR

[ctc17]

I was going to say low line voltage could be the reason too.

You can open it up and switch 2 wires and it goes from increasing the voltage 1 volt to reducing it 1 volt. Some of them are isolation, it should say on the cardboard tube.

[damen]

Here is a picture of the Zenith working..I said I would post one. I still plan on recapping it but it works as is there is no brightener on the tube and it has not been rejuvenated it does warm up a little slow when it sits for days but has good picture.

[DaveWM]

What caps are you planning on doing, if its working well.

The only caps I generally replace are the coupling caps to the HOT and the 1kv white tube caps think there is one near the damper and the vert circuit.

the vert cap will cause it to be jumpy (vert). I do the HOT cap just because if it goes bad it can damage the flyback.

If you are not having any issues and the cans are not getting very hot, I would leave it be. I have a lot of sets from that era, and often all the cans are just fine.

[damen]

Originally Posted by DaveWM

What caps are you planning on doing, if its working well.

The only caps I generally replace are the coupling caps to the HOT and the 1kv white tube caps think there is one near the damper and the vert circuit.

the vert cap will cause it to be jumpy (vert). I do the HOT cap just because if it goes bad it can damage the flyback.

If you are not having any issues and the cans are not getting very hot, I would leave it be. I have a lot of sets from that era, and often all the cans are just fine.

I know there are some black beauty or bumble bee caps and I was thinking of replacing the cans for safety. Thanks for the info on this you are right about the vertical it is a little jumpy.

[DaveWM]

yea the bumble bees for sure have got to go. sometimes the black beauties are ok, used in the horz tank circuit and are 10%. they are often ok but I would replace them as well.

On the cans I swear I often wonder if new ones are better (E caps that is, the film are for sure better), esp if the old ones test good. i generally use my old school cap tester and will compare them (out of circuit) with a brand new one. if they test nearly the same (I have had new ones not test as well as the old ones) I figure leave it alone, I dont always trust that new caps were designed to last. I know there are some new tall thin caps coming out from mouser, I sure would like to see how they hold up.

One approach would be to simply fuse the B+ with a fast acting fuse of a conservative value. That way if a old can ever did go south it would just blow the fuse and now you need to deal with it. I know they have circuit breakers, but I would trust a fuse more. You may blow a fuse now and then if you quick cycle the on off switch, but in normal use the B+ current ramps up nice and slow so you could use a 750ma which would be 150% of normal current, and would blow quickly if a can shorted.

Just something to think about.