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  #31  
Old 10-05-2011, 11:07 PM
tubetwister tubetwister is offline
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Magnavox/Sylvania/Philips--4 legged cap would go open, causing the HV to go to 50-60 kV. Usually arced right through the CRT neck into the yoke windings, neatly cutting the neck off the tube.
I had that happen to an 80 Magnavox about 2 yrs after the crt and tuner were replaced that thing was a pita .
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  #32  
Old 10-06-2011, 07:55 AM
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Talking The 70's were fun with vintage TV

[
Quote:
U]Our class had a full compliment of test equipment: O'scopes, Sencore CRT tester rejuvinator, Sencore tube tester, marker generator, etc.

I had a ball!!!!! Wished I'd been born 20 years sooner.[/U]
I used that experience to land a job as a bench tech for an electronics mfr (when there was such a thing in America), for whom I worked for 8 years. I now work in network design for a Fortune 500 company.[/QUOTE
]

Vo-tech (78-81) was my favorite time in the public school system. We had a teacher that was in the Air National Guard Reserves. He separated the goofballs from the serious freaks; The burnouts repaired tape players and car stereos and WE learned the basics - ohms law, AC circuit theory, amplifiers, tubes, transistors, oscillators ...etc, but I was one of a few who bothered with TV's. The shop had a B&K 1077B television analyst, which really helped you zero-in on the problem. It was sooo much fun when you didn't need to make a living at it. I worked for TI in Dallas after tech school. Everybody near Dallas seemed to have old Zeniths! A long and winding road brought me to electrical power engineering for the state GS dept.
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  #33  
Old 10-06-2011, 11:06 PM
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Those were the days!

I was not only in vocational electronics class, but I worked at a shop as well as "on the side" back in the seventies. There was plenty of work, and I didn't have to advertise for myself either. I'd do house calls for 10 bucks and made good money with CRT and flyback jobs. I saw lots of Zeniths/RCAs followed by everything else. I'd fix some B&Ws and repaired sets for resale too. Have tube caddy will travel!

You had to have a good relationship with the wholesale suppliers but they didn't mind "cash" customers! I did a lot of business with my Sylvania jobber.

I think it must have been some "mandatory" requirement that your High School Electronics Teacher had some military experience as well as being of "character"!
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  #34  
Old 10-07-2011, 01:58 AM
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If they had had electronics and/or TV repair in my high school (in Chicago in the mid-to-late 1970s), I might have stuck around there even. Instead, that is what I tinkered with when I was cutting classes!
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Quote from another forum: "(Antique TV collecting) always seemed to me to be a fringe hobby that only weirdos did."
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  #35  
Old 10-07-2011, 05:31 AM
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No vocational classes were offered at my high school - all college prep curriculum. One year I was forced to choose between theater and ceramics. Mein Gott. I can't tell you how perfectly natural it felt to fail that ceramics class.
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  #36  
Old 10-07-2011, 09:09 PM
mbates14 mbates14 is offline
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only tech prep/vocational class i had was IT. i chose between IT/Broadcasting Arts/CAD. So i went with IT.

no such thing as electronics anymore. Maybe in china, not here...
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  #37  
Old 10-07-2011, 09:47 PM
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Graduated from a Vo-Tech HS, where I majored in electronics. During freshman year, you were exposed to 8 different career fields, 2 per semester, then you declared a major for the next 3 years. In addition to electronics, I learned a bit of carpentry, machine shop, plumbing, HVAC, auto mechanics, auto body, and welding. All useful skills, and certainly helpful in reducing the number of times I have put a car in the shop or call a repairman in to fix something around the house. TV repair was a good chunk of the curriculum, and took up about half of Junior year. We had a couple specially built training sets (one RCA-based, one Zenith-based), where the instructor could induce various problems by means of a lockable "control panel" built into the side of the cabinet. We also fixed a lot of sets for faculty and students, at no charge except parts at cost.

Of course, the school is no longer a Vo-Tech school anymore. Teaching people how to actually build and repair things apparently became obsolete in the "new economy".

Last edited by N2IXK; 10-07-2011 at 09:55 PM.
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  #38  
Old 10-07-2011, 09:58 PM
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Bout 3-4 years back I had a PLTW (project lead the way) Digital electronics course in my junior year of HS. It was really fun! My class mates were always cracking wise and jokeing around. Our teacher was a hard ass, but put up with and even joked along with the class. I remember supriseing him good when after having missed two of the three classes in which we were suposed to finish building the kit (this kit would be needed for all future projects) I built nearly the whole thing in one class and took only a few minutes in the after school session (which was to get the slower kids caught up). The guy was totally suprised that I knew how to solder that kit together so fast. I learned a bunch of interesting things about digital circuits (most of what we learned was AOI logic and counter/timer circuits using 74 series logic).

I really got alot out of that class. In fact not long before started we useing flip-flops and timers alot of the kids were wanting to make the 7-segment display count, and I went ahead and built this Rube Glodbergien AOI logic monstrousity that could actually count to about 8 (because the damn thing used so many chips it would overload the power supply if I added the circuits to count higher! ). The teacher took one look at the hand drawn schematic and said "I'm not going to even try to understand how it works", and he used to work on this stuff for a living!

Sorry to go off topic. The recient posts just reminded me of that time and got me all nostalgic.

Tom C.
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  #39  
Old 10-08-2011, 10:10 PM
mbates14 mbates14 is offline
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When i was in collage for electronics, I had one teacher in DC Electronics that was jelous of me, and everything that I did. he was also ex-military and ran his classroom with an attitude like it was the military...

Anyway, anytime i would get my lab for the day completed, I would pull out something of my own personal stash to work on, which at the time was a scanning disc TV circuit (was into that stuff at the time), and he got on to me that i needed to focus and worry about what needs to be done now, and not something else... pissed me off... oh well. So even though i got the lab for the day done, he didnt want me working on something more advanced than what the other students were doing, (i was being questioned about it by others..) I guess it pissed him off too. LOL so he ended up giving me more paperwork to do for that day...

Never had an issue with anyone else from any of my classes. Just him... But the funny thing is, further in time, one of my other teachers wanted me to bring my project in for open house. Which was a color RGB scanning disc set that I had run off a CD player, etc... I had a knob for everything, Red gain, Green gain, Blue gain, Tint, sync level, etc...

Of course when i went back to pick it up at the end of the day, the DC electronics teacher couldnt stop playing with it. Ironic....

Last edited by mbates14; 10-08-2011 at 10:14 PM.
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  #40  
Old 10-09-2011, 04:44 PM
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holmesuser01 holmesuser01 is offline
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I started messing around with TV's in the mid 1960's. I was around 11 years old. I went to work in a real shop in 1975, and had a blast. Opened my own shop in 1979. I have fond memories of Sylvania tube chassis with lots of overheated resistors in the Y circuitry, lots of RCA flybacks, along with Maggotboxes. I remember replacing disc capacitors in the AF circuits on portable RCAs. We rebuilt alot of Motorola modules, and Zeniths... 9-160's and vertical modules, mostly, Oh yes, the early 70's RCA consoles with the MAH (or similar) modules where the module connectors would break if you looked at them wrong!!

I vividly remember taking in a full size Maggie entertainment center that took up all of the room on the sales floor, fixing it, and getting the aroma of hot urine allover the space. Seems that a cat used the set for its toilet. The owner couldn't be contacted right away, so we sat it outside and let it play for a day, until the stench went away. The set stayed with me for over 2 weeks before we got in touch with the owners, who then finally came and got it a few days later. During this time, I obsessed about it getting scratched, as other than the urine, the thing looked mint. I was so happy when it was gone, and the check cleared.

I never took an entertainment center into the shop again after that. I usually repaired them in the home, or pulled the chassis.

Last edited by holmesuser01; 10-09-2011 at 04:49 PM.
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  #41  
Old 10-09-2011, 05:42 PM
old_coot88 old_coot88 is offline
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Originally Posted by holmesuser01 View Post
...I have fond memories of Sylvania tube chassis with lots of overheated resistors in the Y circuitry,...
Ha. Did you get any of those hybrid Sylvanias with the 2-watt collector load resistors on the two demod transistors? The resistors were carbon comp, and ran pretty hot to begin with. Over time their phenolic casing would carbonize, creating a low resistance shunt that would run hotter and hotter till one of the transistors would pop and the other was about ready to pop. We replaced each resistor with two 2-watters in series, doubling the wattage rating (and of course replaced both transistors).
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  #42  
Old 10-24-2011, 10:41 AM
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holmesuser01 holmesuser01 is offline
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Sorry for the long delay in replying to you...

I rarely got a hybrid Sylvania set, but one that I did get to keep, was a 19" with no color. The B/W image was perfect, though. I never got into it enough to fix it. Eventually used the CRT in another set.

I never saw any hint of color in anything we viewed on this set. Too bad, as it was a nice looking set.
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  #43  
Old 10-24-2011, 11:05 AM
old_coot88 old_coot88 is offline
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Originally Posted by holmesuser01 View Post
...I rarely got a hybrid Sylvania set, but one that I did get to keep, was a 19" with no color. The B/W image was perfect, though...

I never saw any hint of color in anything we viewed on this set.
That's exactly the symptom you'd get if both demod transistors were popped. If only one was popped (the usual condition), you'd get really weird color with half the chroma information missing.
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