On Porthole CRT safety ...

[cwmoser]

Was reading a thead on adjusting the Buzz control on a Zenith
Porthole TV. My Zenith Porthole TV uses a metal CRT - 16EP4 and
there is 12,000 volts exposed just inches from some adjustments.

What are some safe ways you guys have found to deal with this
large exposure of high voltages? Any kind of shield? I would not
think TV repairmen back in the day would want to stick their
paw deep inside one of these consoles to make adjustments.

Carl

[Polaraligned]

Originally Posted by cwmoser

Any kind of shield? I would not
think TV repairmen back in the day would want to stick their
paw deep inside one of these consoles to make adjustments.

Carl

Was there not a plastic sleeve that was installed around these CRT's from the factory? I guess a lot of them, like mine, are missing.

[Username1]

Use thick gloves, and keep one hand in yer pocket.
and, or slide the chassis out a little, be sure you supplement
the ground strip to the crt. Adjust the thing from the
underside if its possible.

.

[kramden66]

what i did / do is take the plate cap off the top of the 1b3 hv rectifier , stick it in a bottle cap and put electrical tape around it , this way it doesn't touch anything , this removes the voltage from the metal of the crt and makes it safe to go and do the adjustments

[cwmoser]

Originally Posted by kramden66

what i did / do is take the plate cap off the top of the 1b3 hv rectifier , stick it in a bottle cap and put electrical tape around it , this way it doesn't touch anything , this removes the voltage from the metal of the crt and makes it safe to go and do the adjustments

Do you mean something like the cap on a plastic Coke bottle?
Have to try that. The Buzz control is very near that big metal CRT
bell housing and adjusting that always made me nervous.

[kramden66]

yes soda , water cap

[earlyfilm]

Originally Posted by cwmoser

I would not think TV repairmen back in the day would want to stick their paw deep inside one of these consoles to make adjustments.

We did not want to, but did want to get paid at the end of the week!

On most of the RCA style sets, the CRT stayed in the cabinet, so we placed a work-quilt on top of the set and plopped the chassis on top of that. We had aftermarket yoke and HV extensions for most sets and used those. It a set carried an odd-ball yoke plug, one cut the wires a few inches from the socket and spliced in 4 foot extensions. Once the repairs were done, we removed extensions and covered the splices with some of that new-fangled heat-shrink tubing.

We were lucky that there was no Zenith dealer in our area during most of the metal CRT years, but when one of those sets came in for anything more than a simple tube change, we used a small all-glass CRT test tube. We never would trust the plastic CRT covers on any B&W set.

If you were servicing the set in a home, your first would check to see if the floor was wood or concrete to access your shock risk, and in addition to HV worries, this risk included hot chassis sets. (I've been bit by hot chassis sets while wearing rainy day damp shoes on a concrete floor, than ever have from the HV.)

A rather not funny at the time accident happened to my boss back then. He was a little overweight and normally did not go on house calls anymore, but was caught when a loyal customer's set went out one evening near closing time and the road crew had left for the evening, so he made the call, and it was a metal CRT. I was just learning the trade and went along to help if he had to bring in the set. While working on the set, a gap opened between his shirt and pants, and the set owner's friendly dog wandered over and cold-nosed him. He jumped, got bit by HV, and turned the air blue.

Needless to say. the set owner's children learned some new words that evening.

Moral of that story: Don't work on a metal CRT set with a dog about!

Most of the plastic covers on the early metal CRT color sets were better made and lasted until the CRT's failed and the owner traded the set in. The color sets hurt much more than the B&W sets if one got bit.

With 20/20 hind sight, we could easily have made a HV shield from a junked color CRT cover to add protection on the old B&W sets, but it never occurred to us, as we had accepted the risk for so long.

James (who left active TV servicing in January 1961.)

[cwmoser]

Hey James, thanks for the story. I love reading about you guys
reminising about what it was actually like in the TV repair days.

BTW, would putting a plastic clip board between your hand and the
metal CRT eliminate the possibility of shock? I was wondering how thick
the plastic would have to be to be safe.

[old_coot88]

It's fun hearing tales from someone who got into this stuff even earlier than I did.
My illustrious career spanned from the mid-fifties to the mid-eighties, with a gradual phase-out as the detested "souped-up adding machine" (digital throw-away stuff) supplanted the old craft of troubleshooting discrete components.

[cwmoser]

Wish you guys were my next door neighbor - I could learn a lot from you.

I have a 1948 Philco 48-2500 projection TV that I restored. Got to communicate
on here with a guy who actually serviced that type TV. Interesting stories
of a bygone era.

[Big Dave]

5axp4