As a retired So Cal radio spot writer, I admire your “appreciation” for descriptions that polish the turds so generously gifted to unwary consumers. I made my living doing that. And, as a radio/tv kludgemeister, since the age of ten (I'm 70 now) I enjoy your videos 100%. They need NO polishing.
I've been repairing consumer electronics for 30 years and rare is it to find a troubleshooter with methods like my own. I never worked on tube equipment and don't have any interest to but I could literally watch you troubleshoot a damn sewer pipe, oh wait!
Shango066 You are one fascinating dude, your commentary stylings are the BEST! The items you select to diagnose never fail to blow my mind. Hard to believe that it's even possible to resurrect ANY of these things! But of course the Mine Exploration is what brought me here... Top shelf content man. THANKS!
Heat that C.R.T. up and discharge a charged 20uf @450 volt cap between the heater and cathode a few times. It's either gonna fix it or phuck it. Thanks for the great educational troubleshooting video.
I love that brief brain failure Shango, I suffer from that too sometimes. Brilliant desert TV resurrect. Great CRT minus the fault. That FLIR camera is awesome.
Validates the method of pounding on the top of the set to improve the picture. We had a Zenith “wildcat” which was about the same age and size. It was a trooper...a dim CRT did it in a few years ago
I remember reading one common trick for that problem was to use a turn or two on the core of the flyback to power the filament in the case of an H-K short. There'd be relatively little coupling since it's 15KHz and only a few turns vs. a 60Hz iron core transformer.
This is the best demonstration of a picture tube with a heater-cathode short I have ever seen! I think the white insulating powder on the filaments is aluminum oxide. I have a bunch of old tv service books that talk about using 1:1 filament isolation transformers (they look identical to filament booster transformers) to remedy this problem, but apparently they never mentioned that it was not a complete fix. I wonder if it is possible to rewire the circuit to feed the video information to G1 rather than the cathode, as some sets did from the factory, to avoid shunting the video info to ground through the transformer. The thermal imaging cam will be an awesome diagnostic tool. Great video, as always, Shango066.
One idea (just for kicks and giggles if you don't care about blowing it up) - hook up BOTH heater pins (in parallel) to one side of a car battery, then the cathode to the other, then tap the CRT. I'm not sure if 12v will blow the filament open, but quite close. The amperage will absolutely fry whatever's shorting it though. If the heater is loose and is touching the outside can itself it will melt it. :)
I was going to mention something about peoples fear of the H.V. on TV's. I am an auto mechanic and have, on more then one occasion gotten wacked by a modern ignition coil and FUCK DOES THAT WAKE YOU UP!! If you have never seen the energy they release its quite incredible. The spark will jump a 1" gap easilly and its a thick hot blue spark not the thin anemic spark a flyback makes! I am glad shango mentiones something about it!
Shango, I’ve been watching your “resurrection” videos for quite some time now. Thanks for the diagnostic sagas, giving a final useful purpose for these farewell sets. There’s no way I would have ever learned so much about these old tube NTSC sets .. they are the “Simpson gear set automatic transmission” of the electronics world. A fascinating ingenious invention relatively unchanged, universally used, throughout the decades …
Repair shop owner would get mad if we took these in for estimates back in the 80's. Started to charge $20 .00 for estimates. They were considered junk then. excellent repair and video as usual.
I personally don't think shango066 is a fake he's attempting to do a lot of things that a lot of other people out there wouldn't even attempt to think about doing I think his videos are very educational I stand behind him watching him 100%
Thanks for the videos. Beats anything else on TV. Back when I used to work on these things, I used a 1000x attenuation HV probe to measure voltage on horizontal output plate, etc. It acts like a low pass filter for those pulses so it won't damage the meter. ALSO, I used to play with infrared photo film and noticed that the optical and infrared images were displaced like your device. I think it is difficult or impossible to color correct lenses for that large difference in wavelength of light.
This vintage TV brings back my early teens. I would take the tubes my Dad taught me that were important to test, or the usual suspect. I was testing the tubes at a RadioShack. The guy behind the counter asked me how do you know how to test these tubes? I said my Dad taught me. Dad also taught me how to drink. Jk
Hey Shangoo, this TV is a rare one. I tried finding even just a photo of this exact set that would have all the knobs on to see what type of knobs these sets had. So far I couldn't find an exact photo of the set. You mentioned in another video that all of these set you received/picked up; had no knobs on the front. Either the knobs melted from the heat; fell off and got buried in the ground; or someone snatched the knobs off to leave the sets rot away. I hate when vintage electronics like this get abandoned and abused.
The vu-brite brightener came from an area close to my childhood home. I lived in the 60645 area code, and the one on the brightener was 60646. Small world.
Sometimes when I watch your videos, I think, "Yeah, I get it, and I would have followed the same path. " Not this time. I would not have had a clue. NICE JOB!
Makes perfect sense. Notice that the horizontal lines as well as the very top and bottom of circle are unaffected by the short. Those are low frequencies, while the sides of the circle are high frequencies. The high frequency portions of the video are being shorted to ground via the inter-winding capacitance of your isolation transformer when the cathode and heater are in contact, while the low frequencies are unaffected. If you used a multiburst pattern, you would really see the frequency-dependent effect of the short.
I would have tried the Clear Shorts button on your CRT tester. As a kid in the 1980s, I built a short killer from a schematic in a 1960s Popular Electronics magazine. I seem to remember it used something like a 10uF 450V capacitor and would dump that capacitor across the shorted elements on the tube. I only needed to use it once, I remember the bright flash from inside the neck of the tube.... and guess what, the tube worked again! Your mileage might vary... LOL. Especially with an H-K short where it's probably a crack in the ceramic coating on the filament. But hey, the CRT is useless otherwise, so it can't hurt to try something like that. I have heard of people getting color tubes with one heater open to work using similar tricks. The arc from the high voltage applied by the capacitor is supposed to weld the broken filament together, and the fact it's a brief pulse of high voltage doesn't allow the heaters time to overheat and be damaged. Again, last resort stuff, and not something I would trust as a permanent repair for a paying customer. Alternatively, you could buy a vacuum pump and take up glassblowing as a hobby. LOL.
Amazing! You keep coming up with um. What a great lesson to illustrate the value of voltage checks. I haven't even finished the video and had to comment! You are really something. Someone mentioned the flyback wrap trick. Would really be interesting to see if that works.
I'll bet that set was left not long after new. With emissions like that it's got to be low hours. The storage conditions over time is most likely the cause of the short.
Maybe, but it wouldn't be atmospheric conditions---the working parts are sealed in a vacuum. Now if the set was dropped or subject to an impact, that could loosen or shift some of the elements....
The CRT H-K short can sometimes be removed... Heat up the filament, charge a 100uF capacitor with a diode on the power line. Dump the capacitor across the heater and the cathode terminals - the capacitor might blow away the short, you're unlikely to fry the filament(s) unless you go crazy on the capacitor. I got a 1965 Onkyo color portable to work that way, series-string, one gun's cathode shorted to filament. If an isolation transformer isn't practical, you have nothing else to lose. This is similar to how the short-clearing modes on some CRT tester work, but it's one button that could doom the CRT if a tech accidentally hit it in the field, so H-K short requires a little more finesse. If it's a parallel set, the smallest 1:1 60Hz transformer you can find should be okay to isolate the filament. Bigger transformer = more stray capacitance = more rolloff of the high-frequency picture info = more smeared picture. Parallel sets don't fail the same way with an H-K short in the CRT, but the image still gets smeary because the entire filament circuit is now part of the video output. The capacitor trick might work, but I would never use it as anything but a last resort before having the CRT rebuilt (if the set is worth it). If you still have that RCA, it would be a perfect candidate to try it.
You should be able to isolate the added filament transformer from the video signal with a pair of chokes, one choke in each wire going to the fil. Transformer secondary. Maybe even two chokes in each leg, one rf choke and one for lower frequencies put in series.
A. Dog Yes. If he has one on hand. That 6.3v fil xfrmr is going to have huge capacitance between pri and sec windings. Either way should make a huge difference.
MrJohhhnnnyyy Problem with using a single high value choke is that it may have too low a self resonant frequency. Way around it is to use two in series. First blocks the high freqs and hopefully has a high enough SRF that it acts like an inductor at the highest video frequency present. Then the higher value choke in series takes care of the lower freq components in the video signal. May have to experiment with actual values a bit to get it right. Yes I agree must do chokes in both fil leads to have any effect.
One trick I used to use with heater cathode shorts in CRTs was to wind a couple of turns of wire round the flyback Transformer’s core to supply the tube heater. That way there is much less capacitive drag on the video signal.
Try turn TV up side down temporary. Gravity will pull down the filament .Short could go away. If helps , then you can flip the CRT. I had fixed many TVs that way.
Up in Des Moines Iowa there was a guy who would recondition old picture tubes, basically rebuild them, he'd recoat the screens and install a new gun assembly. Sadly, he closed up his shop a few years ago due to crt and picture tubes being obsolete.
The easy fix for a heater cathode short is 3 turns of double insulted wire (2V/turn) around the horizontal o/p transformer ferrite core to supply the filament & it won't show any symptoms of the short, eg video quality degradation, I did this with many hundreds of TV's back in the day.
You just got to want to shake this guy's hand, 10 out of 10 for effort mate. Yep, many years ago Ive tapped a few tubes, but was never exactly sure why :-) Something very deep in the dark recesses of my mind, did we used to wrap half a dozen turns of well insulated wire on the LOPT and use this to heat the tube? All been a long time ago now, but Shango's videos have to be the best on RU-vid. Keep the faith mate.
I have a little 2005 Toshiba dvd tube tv combo it has great picture a friend got it for me on the side of the road and it came with the original remote
Gosh!! We sooo needed that big arrow in the thumbnail to know this would be a video about a television. What is it with this "fad" with arrows on RU-vid thumbnails lately???
When you have an arrow, or a circle or a little pointer finger, anything pointing to some part of a picture in the thumbnail, people will check in just to see what the thumbnail is trying to draw attention to.
Ohh, that thumbnail... If it weren't for that I'd have clicked on a pop video instead... ;) Can't wait to get into this vid and see the dark platinum mist & dead birds I'm promised by the comments section...
Quite unusual to see a CRT picture go "fuzzy" then "clear" just by tapping the screen. Weird. At least there is no obvious "cloudiness" of the picture. Sadly there is not much anyone can do about that bird - it's officially EOL'd.
Yes, as 'kevtris' said, heating it from the flyback will solve it, I've done that before. And I've installed a bad EF80 (6BX6) tube in the heater string as a 'dummy heater' to prevent the other tubes being overheated. Then the RMS voltage of the CRT heater also should be tweaked with a series resistor (or with a variable inductor, it's more convenient to tweak, and causes less additional load to the flyback), it needs a DSO with RMS measurement for the most accurate results. An old light bulb RMS converter will also do it, if it has high enough input resistance. I haven't seen any true RMS multimeters which will do that (altough I've tried only two different lower-end models), they either not liking the 15kHz and/or the high crest factor.
Great video and funny comments. But aren’t there old sets like this, here and there, enough so that rescuing one that was in the mud isn’t necessary? Sure maybe it can be made to work again, but the outside is spoiled.
I’m curious if the CRT was taken out of the set turned 180 degrees and retested would the cathode to Filament short show itself? That would depend on how the degraded the insulating material on the filament is, because the shirt was so intermittent I think that it wouldn’t short if the CRT was installed upside down
There should be a setting on your FLIR camera software to adjust your distance from whatever you're looking at. That should help correct the alignment of the two images.
I use the B&K 465 for testing CRTs, using it I found out my 10BP4 was actually okay, but the high voltage on my RCA T-100 was bad, making the picture incredibly dark and blurry.
I have a suspicion that might as well be the AC from the transformer getting coupled into the cathode through the short. I would expect the inductance of something like a mains transformer to block much of the higher frequencies of a video signal. Because the transformer and filament circuit connects to the rest of the TV on a single point, that loop should have no current flowing into and out of the TV from it, except for capacitive coupling. I have a feeling this problem would be far less noticeable, if not altogether removed, if you ran the filament on filtered DC; maybe if you can find an old six volt wall wart, it might do the job. In another note, I really like these videos in particular, at this point it's not about fixing the TV but to experiment and see what it would take to get it going. Who knows, maybe someday you'll run into a pristine, super rare or otherwise valuable set that has a problem like this.
It's interesting to me that you decided to do a clickbait thumbnail for your video, like I tend to see for some "urban exploration" videos, but after hearing 0:25, I now understand why.
