Does this description make sense?

[venivdvici]

I think I found the manual for the RCA CTC7C. May be 7AC. May be both.

http://www.earlytelevision.org/image...ice-manual.pdf

[venivdvici]

Thanks! My main character is actually a teevee repairman circa 1961 fixing a 1957 RCA CTC-7C. So the teevee owner's complaint would be, "The picture's messed up. It's got a black bar that keeps rolling up and the sides are wiggly." So the repairman would right away know the main filter capacitor was bad? Why wouldn't he fix it at the home? Thanks!

As for the sneakers and hand in the pocket, the repair manuals I have say to do that. If no one ever did that, I won't have him doing it!!!!

Originally Posted by old_coot88

TThat sounds like a few of the old biddies i ran into during my years as a road techie (as well as an in-shop techie).


Well, first off i never knew a road techie who 'wore sneakers' specifically for electrical safety or kept one hand in pocket while working on a set in-home. I never knew one to routinely carry a tube tester into the home either. The test for a given symptom is to substitute the suspected tube(s).
But to address your specific scenario of a shrunken raster on the CTC-7, the very first thing the techie would know to do is substitute the 5U4s. But since there's no improvement, this indicates the 5U4s are not the problem. However the shrunken raster exhibits a hum bar, that is, a dark band that slowly scrolls vertically through the picture, accompanied by an S-bend in the sides of the raster that scrolls with it. This is the classic symptom of the main filter capacitor gone bad. The set would have to be shopped for this repair.
But note that the raster could not be "very small" and still display a picture. It would be pulled in maybe an inch or two from the sides along with the telltale hum bar.

[old_coot88]

If you go down to fig.# 46, you can see the main filter cap, actually two of them, designated C104-A and C105-A. If these dry out and lose capacitance it'll cause the shrunken raster and hum bar described earlier.

Why wouldn't he fix it at the home? Thanks!

To do a correct repair is a pretty involved process. It involves unsoldering multiple connections, untwisting the 'Twist-Lock' lugs that hold the capacitor can(s) in place, (sometimes) drilling out rivets, re-installing the new can(s) and re-soldering the leads back onto the correct section of the can (a single can can have up to four sections, designated A, B, C etc.). Although it `could` be done in the home, it would not be practical. Anything much beyond tube or fuse replacement was generally a shop job. Sometimes with a big heavy set or combo, the chassis was pulled to the shop, leaving the cabinet and pic tube in the home.

As for the sneakers and hand in the pocket, the repair manuals I have say to do that. If no one ever did that, I won't have him doing it!!!!

That's an obligatory precaution given to neophyte newbies and well worth the warning. But a seasoned techie such as depicted in your novel would not likely be seen working with one hand in pocket. He might be wearing sneakers, but not specifically to avoid electrocution in the customer's home.

[venivdvici]

Cool. So why would he need to bring it to the shop? I just need a reason why he doesn't fix it at the house.

Does this sound okay?
=================
A few years earlier, Mrs. Amato blew almost eight hundred bucks of her late husband's insurance on the '58 RCA Anderson with the CTC-7C chassis and complained when all her shows weren't in color. He explained most shows weren't broadcast in color and she should save her money and return it for a nice black and white set. Nope. She wanted to be ready for the color revolution. She'd read in Life it was coming.

Her problem was, "The picture's messed up. It looks smaller and it's got a black bar that keeps rolling up and the sides are wiggly." A shrunken raster, hum bar, and S-bend. At her house, he tried replacing the 5U4s, but that didn't fix the problem, so he brought it back to the shop.

While Yoyo was out of his hair, he sat down with the heavy monster. It had 28 tubes, drew 380 watts of power, and had over 22 kilovolts of zapping power. Once he was familiar with its layout, he found the problem--a dry C104-A and C015-A. He replaced the main filter capacitors, and the set ran good as new.
=====================

Also, I'd like to use the vacuuming/degaussing problem noted earlier. I can use it later in the story. Would this work? (I'll rewrite it for the scene. I just want the facts straight.)
=========================
Mrs. Amato was vacuuming and degaussed the picture tube, creating a swirling rainbow mess on the screen as she moved the sweeper back and forth. With no degausser circuit on the CTC-7, the image was stained. To restore purity, he used a demagnetizing coil.
========================
Would he do this at her home or would he have to bring the set to the shop?

Thanks. Merci beaucoup. Mucho gratias.

Originally Posted by old_coot88

If you go down to fig.# 46, you can see the main filter cap, actually two of them, designated C104-A and C105-A. If these dry out and lose capacitance it'll cause the shrunken raster and hum bar described earlier.

[old_coot88]

Originally Posted by venivdvici

Also, I'd like to use the vacuuming/degaussing problem noted earlier. I can use it later in the story. It causes a purity problem. I just don't know how he goes about fixing a purity problem (and if he needs to bring it in the shop).

Thanks.

OK, the vacuum cleaner motor puts out a strong magnetic field which can magnetize the shadow mask in the pic tube. This causes the three electron beams passing through the shadow mask to incorrectly 'register' when they land. That is, they don't land perfectly on the correct phosphor dots, and partially illuminate the adjacent dots. This screws up the color purity. (For example, an all-red screen will have blotches of the wrong colors in it.)
The shadow mask can thus be said to be "gaussed" by the vacuum cleaner (or any other source of a magnetic field).
DEgaussing is done to restore the purity. It's done with a tool called a degaussing coil. It's a hoop about a foot in diameter with a momentary contact push-on button and a long cord that plugs into AC. There's a special technique (NOT the one shown in the UTube video !!!!!!). The coil is switched on while at least 6 feet away from the TV set. The coil is slowly brought in to the CRT face and moved around, and around the sides and top of the TV, then slowly moved back at least 6 feet away from the set before switching the coil off. If the coil is switched off while close in, it will "gauss" the CRT instead of degaussing it. (Also in the UTube vid, the guy switches the coil on directly in front of the CRT. Wrong!)

In the days before auto-degaussing (which didn't come until the CTC-16), the sets had to be degaussed every time they were moved, or even rotated 90 degrees, because even the Earth's magnetic field would disturb the purity.

Dang, dunno why "the vacyoom cleaner" got formatted in blue. T'warnt me did that.

[venivdvici]

Wow, fabulous detail! All I knew about degaussing was when I pressed my computer monitor button and the screen boinged. You've explained the procedures I need to follow for the degaussing of the gaussed set.

One question: Does the shadow mask only apply to color sets? I figure that's the case, since we're talking about color.

I ask, because I was going to have another customer ask my main character Hunny (Gil 'Hunny' Hunnicutt) move her teevee set. This would be after he put in a wave-trap for an interference problem. She has rabbit ears, so I'd have him suggest an antenna, which he'd wire up through closets to her attic. (She finds outdoor antennae to be 'tacky'.) The mayhem of the story will happen with this customer who'll be kidnapped by an Albanian hit man in drag and the husband won't pay ransom. (Uh, it's not based on a true story.)

As for the links, something is automatically doing that. I didn't link compooter monitor either!

Originally Posted by old_coot88

OK, the vacuum cleaner motor puts out a strong magnetic field which can magnetize the shadow mask in the pic tube. This causes the three electron beams passing through the shadow mask to incorrectly 'register' when they land. That is, they don't land perfectly on the correct phosphor dots, and partially illuminate the adjacent dots. This screws up the color purity. (For example, an all-red screen will have blotches of the wrong colors in it.)
The shadow mask can thus be said to be "gaussed" by the vacuum cleaner (or any other source of a magnetic field).
DEgaussing is done to restore the purity. It's done with a tool called a degaussing coil. It's a hoop about a foot in diameter with a momentary contact push-on button and a long cord that plugs into AC. There's a special technique (NOT the one shown in the UTube video !!!!!!). The coil is switched on while at least 6 feet away from the TV set. The coil is slowly brought in to the CRT face and moved around, and around the sides and top of the TV, then slowly moved back at least 6 feet away from the set before switching the coil off. If the coil is switched off while close in, it will "gauss" the CRT instead of degaussing it. (Also in the UTube vid, the guy switches the coil on directly in front of the CRT. Wrong!)

In the days before auto-degaussing (which didn't come until the CTC-16), the sets had to be degaussed every time they were moved, or even rotated 90 degrees, because even the Earth's magnetic field would disturb the purity.

Dang, dunno why "the vacyoom cleaner" got formatted in blue. T'warnt me did that.

[venivdvici]

BTW, I didn't realize there were examples of this on the yoohootoob. Way cool. I found this first. http://www.youtube.com/watch?v=6MMsYrfLHXs

Others fixed it with a hand drill that had a magnet attached!

[old_coot88]

Originally Posted by venivdvici

Does this sound okay?
=================

Well, being an old geezer who authentically did this stuff for a living 'back in the day', i might take the liberty of amending your text slightly to read thus..

A few years earlier, Mrs. Amato blew almost eight hundred bucks of her late husband's insurance on the '58 RCA Anderson with the CTC-7C chassis and complained when all her shows weren't in color. He explained most shows weren't broadcast in color and she should save her money and return it for a nice black and white set. Nope. She wanted to be ready for the color revolution. She'd read in Life it was coming.

Her problem was, "The picture's messed up. It looks smaller and it's got a dark area across it that keeps creeping up through the picture and the sides are bending in and out." A shrunken raster, hum bar, and accompanying 'hourglass' bending. At her house, he tried replacing the two 5U4 power rectifier tubes, but that didn't fix the problem so he brought the set to the shop.

With Yoyo out of his hair, he pulled the heavy beastie's chassis. It had 28 tubes, drew 380 watts, and had over 22 kilovolts of zapping power. Once he was familiar with its layout, he found the problem-- the main filter capacitor had gone bad. He replaced the cap, a major job in itself, checked the rest of the tubes, cleaned the tuner and controls, re-installed the chassis, did a thorough degaussing and a complete convergence and purity set-up. He delivered the set back home and gave it a final in-place degaussing.
And the set ran good as new.
=====================

BTW, Black & white CRTs don't have a shadow mask.

[venivdvici]

Thank you so much! I'll take your edits. BTW, your nickname isn't Hunny, is it? Ha!

You probably have some interesting stories to tell about your house calls. I was thinking of having someone's pet snake or hamster get stuck in the chassis. I figured the customer would say the teevee doesn't work and it smells funny. Do you know if the pet inside would fry and die?

Originally Posted by old_coot88

Well, being an old geezer who authentically did this stuff for a living 'back in the day', i might take the liberty of amending your text slightly to read thus..


BTW, Black & white CRTs don't have a shadow mask.

[Pete Deksnis]

Great rewrite old_coot88! It's as good or better than Stewart Woods describing an ILS landing.

Pete

[wa2ise]

For the vacuum cleaner "scene" in your novel, you could say that she had the TV set on while she was doing some vacuuming right in fromt of the set. She sees that the TV set's CRT is having crazy colors running thru the picture on the CRT, and thinking that she is slowly destroying the TV set, turns off the vacuum cleaner right in front of the set. And the CRT now has purity issues and dammit I have to have the TV repairman back in. And a note saying had she just slowly kept vacuuming and eventually turned the vacuum off only when she was about ten feet away from the set the funny colors would have gone away (that she would have degaussed the set herself). If it fits your plot line, the TV repairman could show her this trick with her vacuum (maybe to make his customer feel better, good for future business).

[venivdvici]

Ha! She degaussed it herself! Cool. Thanks.

Originally Posted by wa2ise

For the vacuum cleaner "scene" in your novel, you could say that she had the TV set on while she was doing some vacuuming right in fromt of the set. She sees that the TV set's CRT is having crazy colors running thru the picture on the CRT, and thinking that she is slowly destroying the TV set, turns off the vacuum cleaner right in front of the set. And the CRT now has purity issues and dammit I have to have the TV repairman back in. And a note saying had she just slowly kept vacuuming and eventually turned the vacuum off only when she was about ten feet away from the set the funny colors would have gone away (that she would have degaussed the set herself). If it fits your plot line, the TV repairman could show her this trick with her vacuum (maybe to make his customer feel better, good for future business).

[Geoff Bourquin]

Originally Posted by venivdvici

You probably have some interesting stories to tell about your house calls. I was thinking of having someone's pet snake or hamster get stuck in the chassis. I figured the customer would say the teevee doesn't work and it smells funny. Do you know if the pet inside would fry and die?

I've never found a fried pet in a TV, but I have seen some really big bugs get toasted, and once found a dead 6" lizard stuck against a damper diode in a 90s (solid state, of course) TV. I almost trapped someones cat in a Magnavox entertainment center once....got a few screws in the back cover and started hearing funny noises. Found the cat had jumped in just before I set the cover in place.

[venivdvici]

Ack! Stupid cat! Well, since my story is set in 1961 and teevees were mainly tubular, I think a fried snake wouldn't be too bad. I'm not sure how it would play out, though. What would fry it? Would it unseat something and get zapped?

Originally Posted by Geoff Bourquin

I've never found a fried pet in a TV, but I have seen some really big bugs get toasted, and once found a dead 6" lizard stuck against a damper diode in a 90s (solid state, of course) TV. I almost trapped someones cat in a Magnavox entertainment center once....got a few screws in the back cover and started hearing funny noises. Found the cat had jumped in just before I set the cover in place.

[Electronic M]

Some thing like a snake is long enough to touch the chassis and at the same time easily hit an above chassis B+ post and get electrocuted to death.

Most companies had circuit boards then which may have buged the snake enough to keep the critter safe (pokey test points and lots of small above chassis components), but someting like a Zenith or a Packerd Bell which had no circuit boards....Many of these 100% hand wired sets by that time used chassis mount terminal strips that could be accessed above chassis (Zenith REALLY liked useing these) often placing several B+ terminals easily touchable above chassis where that snake could comfortably get to them.