Old School Series - Part 7

I decided to not post any comments at the moment in reference to (p)Resident Gropey Dopey Joey Poopy-Pants' desire for total civilian disarmament. Anything I say in reference to it WILL BE construed (and rightly so) as total anti-government and insurrectionist. So... get lost Fed Glow-Boi, nothing to see here.

Instead, I am reviving my "Old School Series" blog posts. I got reminded about doing this from a tweet I replied to earlier today.

I went to one of the state technical high schools where I studied electronics. In the beginning of my senior year, one of the local TV repair shops called looking for someone to work part time after school and on Saturdays. We all looked at each other but no one raised their hand, so I said, "I'll take it!" and I started there the following week. I was working on the service bench with a couple of experienced older guys and took to it quickly. I also went on pickups and deliveries, as well as spending time with "the old man" doing easy repairs in customer houses. He was a funny old French-Canadian guy that smoked a pipe and always had it clenched in his teeth, even when not lit. One time, a little girl peered around the back of the TV and asked "Whatcha doin'?" The old man looks at her and says "Makin' pills." I still say that to looky-loos to this day. Not only did we do TV's, but we did radios, stereos, reel to reel tape decks, guitar amps... anything electronic. We did car stereo installs (my specialty) and sold appliances that needed install and delivery. We had a huge inventory of turntable needles and cartridges, tubes, electronic components, belts, connectors, and brand specific replacement parts. One whole wall of the building were all the file cabinets containing the "Sam's Photofacts" folders. There was a folder containing schematics and service info for everything electronic (non-military) ever made. There was a subscription service that we got regular deliveries of, and it was one of my jobs to file them. Pretty easy as long as I kept up on it, but sometimes we were busy and I fell behind meaning I had to make time to file them away. Here is an example of what could be found in our large showroom:

This is a Quasar model #Wl9439sp. Early electronic tuner & beautiful wood

We were a Quasar, Zenith, and later a Panasonic and Matsushita dealer, but we repaired all brands.

This is an RCA model #GR778 with mechanical tuners. The cabinet in this example is a little beat.

This is an unknown model from Montgomery-Ward. Dig that high-gloss shine on the top. Real wood!

TV's weren't the only electronics that came in a giant fine wood cabinet. Console stereos had an AM/FM tuner and a turntable. Later models also had an 8-Track or cassette tape deck.

A gorgeous slide top Magnavox console stereo. The left side was either LP record storage or a bar.

 

With the fine wood cabinets and built-in speakers, these things had rich, warm sound. The turntable in this example had the ability to accommodate a stack of LP records at once, meaning it would play for hours. When the stack finished, flip them over and start over for several more hours. Also, the turntables usually had good isolation from the cabinet, which meant you could crank it up when the parents weren't home without getting feedback through the needle/cartridge. A little "In-A-Gadda-Da-Vida" at 10 on the volume knob anyone?

So people would gladly pay to have these beauties repaired because they were a big initial investment. On the stereos, new needles, worn turntable belts, noisy audio controls, or bad tubes. On the TV's, mechanical tuners would collect dust and need to be removed for a thorough cleaning, or the contacts would just wear out and the whole tuner unit could be replaced. Dirty or worn volume controls, or other video/audio controls that would need a good cleaning or replacement. Bad tubes or on later models, circuit boards. The CRT picture tube would wear out and the picture would fade. Usually one of the electron guns would be shot making the colors be off. Lose the green electron gun, leaving the blue and red guns would make everything tinted purple. Or the phosphorus screen would burn out making the picture completely faded. I did a lot of picture tube replacements. This post details a CRT picture tube replacement, a lost art in my opinion. They weren't so much hard as labor intensive, because the entire TV had to be disassembled.

The first thing to do was to pull the Sam's folder for the particular model, but disassembly was pretty straight forward. The TV was laid on the floor face down on a moving blanket to protect the finish. Once the entire chassis was out, there was the cabinet, speakers, and picture tube left. The picture tube was held in place with a metal mounting bracket. The CRT has a model number just like a regular vacuum tube, and many manufacturers and models shared CRT's. The only real exception was a manufacturer like Sony with their proprietary Trinitron series of TV's. Once out of the mounting bracket, the old CRT and the new one had to be handled carefully. If dropped and broken, the implosion could cause serious injury. The new CRT was carefully lowered into the cabinet and into the bracket, then secured in place. It was easy to ensure it was right side up, since the high voltage connection was always on the top. Re-assembly was just doing the reverse of disassembly and getting the chassis back in place. The connector for the electron guns on the rear neck of the CRT was left off for the convergence procedure. The TV was stood back up on its casters or legs. A final check of assembly looking for pinched wires or anything out of place and it was ready to be powered up.

These TV's had an electrical safety interlock. The back cover had to be on and secured to normally get power to the chassis. In the shop, we needed the TV powered up to service it live. We had what we called "cheater cords" to by-pass the safety interlock. This was necessary to do the convergence procedure. Because of manufacturing processes, every CRT is slightly different and the alignment of the electron guns has to be manually adjusted. In an old school CRT television, the electron gun shoots a stream of electrons at a phosphorus screen at a high rate of speed. Our eyes can not detect the constant "repainting" of the phosphorus screen, so the picture looks steady. The red, blue, and green electron guns are "steered" to the different parts of the screen by electromagnets in an arrangement called the yoke. If you don't do the convergence, you will see three separate pictures on the screen; a red one, a blue one, and a green one slightly off from each other. We had a special device that plugged onto the picture tube to generate test patterns for moving the electromagnets on the yoke and aligning the pictures. This took some practice, because you were doing it from behind the TV while looking at the images in a mirror. It was a combination of having the 3 colors balanced by how strong they were, and then rotating the entire yoke as well as the slide adjusters for each gun. It always took me several tries, but the older guys with experience did it fast. We would then connect the CRT to the chassis as normal and hook the TV to the antenna system to let the TV run for a day or so. Sometimes the convergence would need a tweak before delivering the set back to the customer. The final step was to clean the screen, knobs, and cabinet, then polish the finish. It would be wrapped in a moving blanket, delivered back to the customer, and re-connected to the antenna.

I worked at this job from September 1979 to September 1981 with a brief time away to go to Army boot camp and AIT. It was a family business that paid good for a high school kid and just after and they treated me well. I only left to start my 35 year telecommunications/IT career.