Actually I was wondering who Michael Bloomsteyer was, I thought it may have been a real person hehe. but I am from Australia so I wouldnt know,. Sounds like you have a bunch of clowns running things over there too, just like here.,
This set brings back memories of servicing TVs in the 80’s. I worked for an authorized RCA shop part time during college. This is an early XL model with the “Better” module connectors. RCA switched to troublesome plastic connectors in later modules.
What’s with the 3 to 5 years for modem flatscreens? I had a 50” Sony for 10 years then gave it to my brother. TVs are much much more reliable these days!
My Dad was an electronics engineer. Growing up, he said the only TV set he’d work on was a Zenith. We got a Chromacolor 2. A couple of years later, it had developed an issue. He ordered one plug in board from Zenith. While it may seem like using a bazooka to kill a mouse, I remember him saying it was maybe a five minute job. And we got to watch All In The Family again. Naturally, he gloated for months afterwards that he had made the right choice in TV sets. The point being, these sets are a living nightmare to work on, so back in the day, you tried to make a good choice, to anticipate what may happen down the road, in case of a problem. As far as serviceability goes, a Zenith was made with ease of repair in mind, and Bloomberg-ready.
The more I watch and listen to this guy the better it gets. Witty, informative and just so enjoyable to watch. Oh, and I know a hell of a lot, lot more about TV's than I did a year ago. Superb.
When I was a kid, a very young kid we lived on the old homestead established by my grandfather before the turn of the 20th century. Nearby was a family who, according to mom were "good catholic's" insinuating that the female of the family regularly gave birth at the rate of one per year giving the family what was known as stair-step children. Well one of those kids came over and hung around with my dad as he farmed, so finally dad began giving him a bit of pay and called him his "hired hand!" When the kid grew up, he became a Radio Repair guy, and later went to trade school to learn to repair those new fangled television things. Go forward 60 years or so, and the old man is long retired, he was once the only HAM operator in town, now I hold that distinction, but he knew nothing about computers. Well when we moved back home in '97 my mother let it be known at the Senior Center that I knew a lot about computers and suddenly, I became the most popular guy in town with the old folks who had non working computers and wanted to get those emails from their kids! So it was, that I went to the old feller's house and in his old TV Repair shop, long closed with the disappearance of the tube sets, lots of equipment all around, some ham gear on the benches which made me drool a bit, but there sat his ancient computer it was a Pentium III but it had problems, mostly just viruses and other crapware that old folks didn't really understand how to avoid. So I cleaned up his machine for him and got it back up and running so he could get those emails from his great grand kids. We got to talking and he told me that he hadn't had a TV now since the broadcast stations changed over to that new fangled digital crap. I looked around his cluttered shop, and there, new in the box was a converter box. I went over and dusted the box off and told him that this was what he needed. He had received it as a gift years back when the change over first happened but didn't have any idea how to use it. Now he had the tallest TV antenna in town, as it was mounted on his 100 foot antenna tower for his ham set, so I convinced him to hook it up to that antenna and see if he could pull in the digital signals from the far away TV Stations (we live in a VERY rural part of South Dakota, no TV Stations within 100 miles as the crow flies.) Well after a bit of tweaking, his set now received about a dozen channels. Both he and his good wife were thrilled! He gave me a door mat made of cut up tires for my trouble, he sold them for 50 bucks a pop so I guess I was well paid for my trouble, and got to hear some fantastic stories of him about what it was like to work for my dad while I was still in the crib at home. So 73's from KE0JBL
I agree with your view on the evolution of electronics and technology in general. It is good to know where we came from, so we can understand where we're going to. Great job, "Rhine Stone Cowboy"... :)
44 years old not bad this is how I was when I was 44 years old a few tweaks later I’m better now so to a very tech challenging piece of electronics but shang066 you are the champ with this stuff
I built a house in Black Forest, Colorado and I bought a TV just like that one for our bedroom when we moved there in 1976. Black Forest was at 8000 feet between Colorado Springs and Denver. Had two antennas on a pole, one pointed north toward Denver and the other south toward Pueblo where all the COS stations had their transmitters. Got great reception on it.
This was our family TV, bought new in 1976. I believe the very same capacitor brokedown ~ 1980. I could not figure it out then. It was repaired by a TV technician. Once replaced it ran for years and years until the CRT was so dim & blurry, it was no longer watchable. It still ran. The RCA was replaced in the mid-80's by a ~ 1978 19" Goldstar in a teak cabinet. Repaired it as a teen, from a lightning strike. That Goldstar ran forever after also. This one still looks great!
I remember those bonded yokes, those came out at the same time I got out of the TV repair business. The yoke is greatly simplified from what the tube sets used, with considerable fewer windings. In order to generate the required magnetic field to deflect the electron beam, high deflection currents were used. In the case of the vertical, the deflection currents are so high, it causes the 4,700 uF cap to heat up, which dries the electrolyte out after a while.
A new cap after more than 40 years and thousands of hours of use is kind of 'adequate'... Of course you are right anyway. I live in Germany and I am amazed by the combination of a inline tube with a SCR-horizontal. When the inliners came in Europe, 99percent of the horizontal sections were transistorized.
When I was still repairing TV sets, open electrolytic capacitors were more common. First the rubber dries, which shrinks it, and then the whole capacitor dries up until it's as dry as a stale fart. But still better than when the electrolyte leaks and spills over other components. I also know the thyristor deflection from our televisions in Germany, 17089h and 17088r were the types of choice for us. I miss the old times.
Built a HealthKit radio when I was 16, 68 now. Love your videos. Don’t always understand them but love to keep learning. The best parts are the strategic video and audio clips you insert that really show your wry humor. Love it!
The Spring with the resistor is a DC-Fuse with high disconnecting current capability. The resistor gets hot , the solder melts and the spring snaps back and quenches the DC arc.
That's why in that case the contraption is in a glass vial. But you are, of course, right. The, unfortunately, common construction using a sand resistor and a hairpin spring is a very bad style.
I haven't worked on one of those in years and those were well built sets that are technically "luggable", instead of "portable." The CTC81 is the 25" version of that chassis and those are paired with a delta-gun CRT.
re: SCR deflection circuit - I worked with the gentleman that invented this circuit when we worked at a graphics hardware firm. Check US patent #3,638,067.
Played Pong on this same model when I worked at Radio Shack early 80's while still i n college! Great nostalgia. When I was in Field Service it was fix the customer first then the machine. Board swapping doesn't always work but can get you out of a bind!
My brother bought a Radio Shack radio kit when I was a kid. I helped him put it together and make a huge antenna. We were getting Asian and European radio stations at night.
You did fine with this, your a competent tech and went methodically through the normal "process of elimination" style of troubleshooting, once you checked those outputs and the Vert/Horz board for shorts and opens that was it, time to return to the power supply. nicely done man.
Thank you for this video. In my opinion it's not that we have a culture of disposing broken stuff, it's about the fact that with cheap manufacturing labour cost makes repairs anti-economical, plus manufacturers don't want you to repair stuff anymore, so schematics are not easily available like in the past, and some custom components cannot be sourced altogether.
I know. Why can't he feed video of a dvd playing a 4:3 tv show, into these tvs? Twilight Zone, I Dream of Jeannie, Dark Shadows, Mr. Ed., The Waltons...
Michael Bloomsteyer. Epic!!!! As usual, a totally sane reasonable and logical troubleshooting path that did not involve the rookie mistake of prematurely replacing the chip!
NBC=RCA at one time long long ago. Very effective trouble shooting here love the end result, complete with clown show. I like that standard feature on all televisions... The OFF control. Well done shango066
I had a suspicion of that capacitor when you were checking the output transistors. I have had high value large electrolytic capacitors open lots of times in solid state jukebox amplifiers from the 70's! I just got a 76 model XL100 TV and was watching you video just to see what was wrong with it. I used to work on them back in the 70's and 80's. Enjoyed the video and from previous videos I knew you would figure it out.
I applaud you at 32:00 for not being a board swapper. I was a Drivability technician at my GM dealership. I worked on engine and body control computers and CANBUS systems. When we got a car in with a bunch of new parts on it, we would say it had the parts cannon shot at it. A mechanic somewhere blindly threw parts in it hoping one would fix it
We always call it shotgunning and it seems to be the way most techs do diag these days. Been a dealer tech for a long time and with Porsche for the last 10, no different in any of them.
I think it boils down to most "tech's" out there only half understand what they're looking at, and don't want to spend the time to learn. The other half (at least for dealers) is working in a flat rate environment. Get it done quickly, take educated guesses, or you'll loose your shirt. I don't know how other manufacturers do it, but back in the day working as a master tech at a Mazda dealer, I had to tag all my warranty parts, with an explanation on why they're bad. If they went back, and tested good, the claim would be bounced, and I'd be called to the carpet for some splainin.
@@bugdrvr I do through diagnostics and tests to definitively find the fault. Throwing parts gets expensive. Had a guy bring me a van several years ago and he was ready to test his hair out. 2 months, 5 shops, $800 in parts, still not right. I did a hour of diagnosis and found the signal reference from the map sensor to the computer was broken due to corrosion at the bulkhead connector. Spliced in a new wire and done
With many tube vertical circuits, the output to the yoke is driven using an impedance-matching transformer. Most vertical circuits using solid state devices have an output with 2 transistors rated for high power dissipation, sometimes coupled directly to the yoke, or in this case, via 'C 409', the 4700uF electrolytic capacitor. With a Philips (equivalent to 'Philco') K-11 chassis, it used 3x 680uF, 50V electrolytic (in parallel) as coupling to the yoke. Managed to diagnose by putting the oscilloscope across the capacitor, finding a typical vertical output waveform! Replaced with a 2200uF, 50V single electrolytic. "Let me finish, thank you..."
Thank you for bringing back memories from my TV repair days in the 80's! That particular chassis did not have the infamous horizontal "Start-Run" circuit where the flyback transformer supplied chassis power. I was surprised to see a good old fashion 60 Hz power transformer. Give the modern TVs some credit though, many of them are lasting much longer than 3-5 years.
I found this model tv in the trash. It weighs a ton. Not exactly a portable but a back breaker. There was a cold solder on the horizontal drive transformer and adjusted the rgb bias and cleaned the tuner This model used the bonded yoke crt
Warren had her swan song and it took out both Bloomberg and Powerpoint Pete. I found a Chinesium RF modulator on eBay that has enough output to serve as an in home transmitter. It has selectable channels so I can transmit on channels 2 through 13. So I now have my own little analog TV station and can actually use the tuners on my old sets.
@@milesprower6641 I dunno how RU-vid feels about eBay links but look on eBay for "Compact RF Modulator Audio Video TV Converter " It will be the ones with the blue plastic on them.
I've got a Curtis that's on UHF channel 14 made in the 90's and it does 300 feet with it's telescopic antenna. Still need to test it for maximum range one day.
I always called them extra large 100 pounds. They were actually one of my favorite sets as far as RCA went. Nice picture when right and modular and easy to work on. The later Zeniths back then were set up similar and I bet I still have some of the Zenith boards. They certainly were heavy suckers, hence my nickname.
The whole time you were troubleshooting this thing and referring to the schematic, you ignored all of those nice waveform picture that you could have used that Tektronix 442 to look at instead of just battling it out with a DMM! When I was a repair-tech, I used a scope nearly exclusively even for voltage checks; many times you can see trouble even though a voltage is correct--you get the 'whole' picture on a qualitative-basis. The only time I used a DMM was for high-voltage, resistance or AC-line voltage stuff. As far as the open 4700uF cap, this is a common failure mode for capacitors that are subjected to continuous pulse-service, where conversely, power supply filters are more prone to shorts due to constant static voltages near their ratings; and of-course, heat hastens all of it.. As far as the RCA XL-100, it was a landmark technology shift for RCA. They had put themselves on a previous 5-year mission to make a quantum leap in the TV industry for both circuitry/performance and manufacturability/ease-of-electrical troubleshooting and mechanical component/module replacement. As a authorized RCA service-shop with a current XL-100 subscription, you could return any XL-100 modules without diagnosis and pull a spare from the default kit that you got as part of the deal. Additionally, RCA actually send out a couple of engineers that gave troubleshooting presentations and they were absolutely excellent---these guys being the actual design engineers were really sharp and loved to tell 'war-stories', it was absolutely fascinating . I remember that evening very well, as it went from 6PM to nearly midnight, with cigarettes blazing continuously! As long as you played ball with RCA, it was a pretty neat ecosystem that smaller shops could not compete with... Anyway, very happy to see someone like you both dabbling in this stuff as well as your dogged-determinism to fix anything even is it is slated for the trash!!!
SCR horizontal deflection using TO3 transistors was common in some mid-70's solid-state sets including the Philips K-9 and K-11 chassis series (and some Sharp TV models) made for Aussie market. A royal pain to repair when it failed (often the HV "tuning" caps (plastic tubular type) connected to the collector of those transistors would go open or lose capacitance causing a dead short). I encountered a lot of these with "blown-up horizontal" years ago, and I only ever had to replace a picture tube as a result of this kind of failure ONCE. ** Great video Shango - I don't know if Bloomberg approves of it but I do. **
Those SCR-type horizontal sections aren't THAT hard to fix. I'm in my fifties and I had tons of them on the bench during the 80s. They were extremely common in German TVs. There are some rules to follow. You have to use the EXACT right parts. Sometime the two SCRs (forward and return) have (almost...) the same parts number. Often a super small "a" or "b" (often printed in a pale red or green while the parts number is solid black) on the case makes all the difference. The caps have to be the exact type specified in the service manual. The most common failure is cold solder joints on the driver transformer or the flyback. Corroded connections on/to the yoke are also fatal. If you fire up a SCR-type horizontal section without the yoke connected; almost everything blows up in an instant. Bad solder joints on the flyback can (literally!!) burn your house down. To test if a SCR is bad, you just short one out and watch the current draw. If it's normal and the other SCR "whistles" a bit, you have the bad one. A bad SCR-type horizontal section sounds like an idling two stroke engine.
Can you tell me what was the point of the service switch just having a horizontal line and how that was suppose to help with repair of a set ?. I dabbled in TV repair years ago but never understood this point.. Thank In advance for your insight
I believe this set uses what a buddy of mine called the "chicken before the egg" power supply...the horizontal circuit uses a "start up" circuit, where the flyback transformer is pulsed (just once) when power is applied, then a low voltage power source on the secondary powers up the oscillator.
you probably mean those sets, where the horizontal output stage was directly mains powered, an all other circuitry was isolated from mains and fed by flyback windings. That was often used in those sets that had video inputs like cinch or scart
You're right these were common sets back in the day. My mom had one of these up until the early 2000's. It was a very high hour set. The flyback gave up the ghost.
Walt's Channel: Also, plenty of “professional sex providers” for those attending and presenting at the debates. Of course all the presenters are prostitutes themselves!
Doorbell? That's the commutating coil for the SCRs... Also, the 74 and 81 were NOT picky about line voltage. It was the Sony's that would puke themselves silly during a brownout. RCA was using SCRs since 1969. Very advanced design.
When I got up today I didn’t think I’d watch the Democratic Debate (that I missed first run) on a RU-vid channel on the internet, shown on a 70s CRT TV. Awesome. This is the only way Bloomberg is watchable! Behind a shadow mask.
watching these videos over the years I find it really interesting that the background and drive controls on US sets are made easily accessible. In all UK sets I saw these controls were internal or required some part of the cabinet (like the speaker grille) to be removed to access them. Probably for the best with the tendency for people to have a fiddle with anything they can see. Likewise the horizontal and vertical controls were often inside. Some sets even stuck the contrast control at the rear.
In Germany the drive controls were quite prominent and easily accessible on the back of the TV. Big red,blue green colored pots. At least on Grundig, Telefunken and Loewe-Sets. When the integrated circuits took over, the drive and bias pots migrated to the PCB on the neck of the CRT.
@shango066 you sir, are a magic man. i watched your truetone resurrection last night and i gotta say, i love your use of being informative and educational but also entertaining and comedic. thanks so much for the vids.
We had one a lot like that. I don't think it died until about 2003 or 4. Its replacement is tube RCA that still works but had that obnoxious Guide + that was such a pain to keep out of the way.
Nobody wants to live in the past, but there is no reason that stuff could not be made better. Yeah, it's cheaper in the short run for junk equipment, but it doesn't last. Plus, though stuff was more money, we had better jobs making the stuff. The people who used to have jobs making equipment today are on public assistance and poor.
A bonded yoke was incorporated into the crt. It eliminated convergence adjustments. Those scrs were expensive back in those days. The vertical output capacitors were a common problem on this model
Those XL Chasis lasted forever! I bought my wife one for our first Christmas together in 1984 and finally pitched into a landfill fully working as the local TV Shop didn't want it. If my memory serves me right, It retailed around $250.00.....
I remember the Remote Controls for this series / time frame RCA offered were the big Black Bricks. Very large remotes that sat on the coffee table I guess so you wouldn't loose it? That TV does have a excellent picture.
Those were the "direct access" sets with electronic tuning and they were very expensive. There was another one that used a smaller remote and a motorized varactor tuner.
I friend of mine blew a console TV in my zenith Allegro console stereo from the mid 70's messing with those convergence nobs in the rear that you were using to check the vertical and horizontal feed.
There is a piece of video art first created in the 1960s entitled "Zen for TV" by video artist Nam June Paik that basically consists of a TV with purposely disabled vertical deflection. So right out of the gate, this TV is a piece of modern art. EDIT: Holy cow, "Stomp!" by the Brothers Johnson!
I can't say that I like modern camerawork, as shown in this debate, one bit! Why is it necessary to keep swiveling the camera around? Do the producers think that if there isn't continuous movement on the screen, the audience will fall asleep?
FYI - You probably already know this - but when you asked "where's the base" - many solid state components have one of their leads (usually the collector or drain on a FET) the case itself, intended to be grounded - but maybe 1 out of 4 times it actually is supposed to be at ground potential. Those plastic insulators keep them from "Grounding out" and the case itself is the collector. I learned this when I was trying to fix an inverter and the MOSFET popped right away, they have a lead AND the heat sink tab with continuity
