Am a technician in Uganda and so much impressed with the way you teach through video .You are so talented in electronics . I ve learned so much from you .I like the way you explain Thanks so much .
an occasional failure in some Toshiba sets, same vintage are some ceramic .01uf caps. at color, contrast or bright control lines to video jungle. will test OK with ohm meter but are found to be breaking down at a few volts. a good clue is the loss of color (or contrast) goes back OK when color is reduced , then brought back up. then cap starts to short again, and color goes. small brown ceramic discs, "103" marked.
I have a 1994 Magnavox I use as my bedroom TV that was bought new for me for Christmas when I was a kid, it gets daily use. It still has a picture as it did when it was brand new. It suffered the 100uf 100V capacitor failure a couple times, and the 2nd time around, a 3.3uf non polar cap dried out taking out the STR regulator. So I replaced the STR (back when you could still get them), and the 100uf 100V cap and a 3.3uf cap with higher quality caps, and its still going. that fix was from 2002ish. No vertical or other cap issues yet, knock on wood!
There is NOTHING like the reliability of old CRT sets. I have some old Sony sets from the 80's and they still work perfectly.I should haul out my old Sonys and just demonstrate them. I have a few from 1986/87 and they have thousands of hours on them.I don't run them much now, just keeping them in my heated storage unit as more of a collectors item, as I am sure in another 20 or so years when there are no CRT sets around they will be interesting. Show them to the grand kids if that day ever happens.
As time goes on, I'll understand more about equipment isolation and the transformer. I'll have to rewatch this video again in the future. I won't you to know I've paused this video because I don't want to miss a thing. I'm still sad about you having to get rid of that Sony Trinitron after you spent time on it and two capacitors and did that resoldering. Looks like there were some vertical lines at the top that still needed a problem corrected but. If I were there, I would've of bought it from you. I love the old CRT sets.
Thank you for the nice educational video. Just to inform you in case you didnt try to repair a SHARP crt tv in past, it happens the exact opposite than here. Sharp uses its own semiconductors and IC's most of the times, where you only can find the service manual (after a lot of search...)of the tv to troubleshoot but no way can you find a datasheet of the various ic's not even for the transistors used for horizontal and vertical deflection. Its like a datasheet was never printed for the various sharp Ic's and transistors used in its TV's.
I realise that it's a bit late to be adding a comment to an article from so long ago, from the UK. But as an ex (retired) engineer from 1958 to 2002, I am often amused by the now extreme accent on safety, which - for a good twenty years of my time - didn't exist. When I started, all TV's had mains transformers, then came AC/DC sets, and we just ploughed on regardless, mostly doing repairs in peoples homes. Many TV's were powered through a two-pin mains plug, so we had to have a 'neon screwdriver' to check which way round the mains plug should be. Getting at least a tingle, was a daily occurrence, and a proper shock, was known as a 'belt'. It was in the mid to late 70's that 'Health and Safety' poked their noses into our lives, and the idea of 'Isolation transformers' were introduced. The idea was to protect us from the mains by removing the reference to ground. In other words, you became the reference to ground because the isolation transformer secondary winding is effectively floating with no reference to ground. They then came up with the idea that workshop benches should also be 'Earth Free', meaning no ground on any of the mains powered equipment - oscilloscope, TV monitor, etc. Practically all modern electronics - including some older CRT televisions, use SMPS (Switching Mode Power Supplies) that keep ground neutral to themselves in a marked 'Warning" area of the PCB... within this area, the only metal should be a heatsink. In other words, the set (whatever it be), has two distinct neutrals - one with mains ground, and one with no actual ground at all, just a DC zero. When working on TV's, I would suggest using an old style oscilloscope which itself will probably have a mains transformer, but even so, disconnect the earth in the mains lead (plug) to protect the scope probe ground. You don't need a modern storage scope for TV ... and whilst I started in 1958 at a large TV rental company, it wasn't until I changed employer in 1961 that I first saw an oscilloscope, and that was largely an ornament anyway... a 100khz max as I recall.
I have a few monitors with burn in. The worst ones were the old amber and green monochrome VDTs I had one that was so badly burned back when I ran a BBS in the mid 80s. Burned a few of them, and an old CGA and EGA monitor. This one was used for security cameras, as was the 20" that I have in the shop. It is nicely burned too. I consider it a great send off for heavily used monitors to have the screen well burned by the time the CRT reaches EOL. I have a couple of BW monitors here that have been running for over 30 years non stop and they still have a good picture.
I quickly learned what a "hot chassis" set was a few years ago!! nearly blew up my scope and blew the bridge rectifier in an old 85' Hitachi 19" crt that i was poking around in lol i really need to just get an isolation transformer so i can work on this kind of stuff.
The quality of old crt sets, i bet that has outlasted quite a few lcd tv lives. Yup i thought cristal too, the older sets had a 22pf trimmer capacitor connected, handy to get it spot on frequency :-). I would not be supprised if the cristal has slightly changed its characteristics over the years. Splatting parts on the underside is my way too :-), once the set works then they are mounted correctly, unless its my unit then they can stay there LOL :-D
Hey ive done that for most repairs, i could not afford new parts all the time so old pcbs were stacked up in a box, i repaired a hell of a lot of c.b radios from those pcbs, i had loads of cb's to repair from all over the uk. I cared that they worked propperly, other repairers didnt give a dam, so they all come to me, not many radios come back due to my repairs. Those pcbs made the customers repairs dirt cheap. I didnt make much money but i didnt care, not a money person.
another good videos safety most be kept in mind. thank you for explain the difference between an isolation Transformer and a variac I was about to buy a variac thinking it was an isolation Transformer I would have really been in some trouble
I've a 2001 - 2002 Citizen TV from the basement with that problem. Fantastic trouble shooting. Circuit layout minor different, but I bet it has the same problem. A burnt out capacitor. Thx! (will test, anyway...)
in UK, still despite the Brexit disaster and prices rise, you can get for Free such tvs or even larger CRTs, people get rid of them due to lack of Hdmi socket....
Yes! I have a few of those TV games. Bought them years ago, at circuit city. Remember them. Pacman was one, and I believe the other is spiderman. My son has it somewhere. I have another one that came preloaded with stuff, and my son now is collecting old NES games. Of course a CRT is the ONLY way to play those, because an LCD is too slow. You are dead before you get a chance to move due to the 3-5 frame delay on all digital sets. Every time I put a small CRT up on craigslist it sells within a day for game use.
my old tv have mains pcb part and floating voltage side , so i guess not the whole chasis is a hot chasis, most of it is not. But the mains voltage part is clearly signed and silkscreened on both sides. Without insolation transformer work on floting part is relatively safe (if we rule out cathode voltage about 200V dc and all the high voltage stuff) And to work on power transformet part... you pop out power driver module and work on it ofline by the service book. Could you show us how to regulate color amplifiers balance and cathode blanking voltages with anaog scope? Any old used tv might have those color problems r g or b overfill, every color might even cut out at a different level causing wierd color compresion, and it wouldn't be the ic.
kokodin, I second this request as I have to monitors with this problem and would love to learn how to fix them for use with old 8 bit computers from the 80s.
The Samsung CRT tv I have has WII,N64,DVD VCR combo /Sega game counsel clone, Roku HD, 50 analog channels . my Samsung tv is 22 years and still works just like it came off they assemble line.
Agreed, CRT televisions were pretty simple devices with very little to go wrong with them. None of this high tech BGA mounted parts with software to go bad. Even when they did break, unless it the CRT was the cause of the failure they were usually fairly easy to repair.
Nazar King Ntsc was used. Now all broadcasting is based on ATSC for 480i 720p and 1080i over the air. For cable we also have 1080p/60 and 2160p/60. Yes believe it or not there are still SD stations. One local one has 3 sd channels on the same carrier and airs old TV shows from the 50/60/70/80s
I have sanyo CRT TV that got form the curb and think its 13'' but I'm not sure and it dose work just fine. I use the sanyo TV with my NES. TV I'm going to try to fix is a 1979 RCA solid state B/W TV.
I know this is an old video but I have a Dell crt that loses its color. If I tap on the sides of the monitor sometimes the picture will get darker and lighter and once and a while it will get a pink tint over the whole screen. I suspect a loose component.
Very good picture your toshiba t.v. may thomson t.v. me company kit problem no sper spart and to kit China kit fit no rizalt no ok original picture please help
You know how many quarters I spent on PacMan back in the day. LMAO I didn't have a isolation transformer but I knew what not to touch. My most severe shock came before I worked on TV's and it didn't have nothing to do with Electronics. So yes I respected the AC line by the time I was working on TV's.
I had a friend that worked at an arcade, and "borrowed" a key and copied it.Fun times, when nobody looking open the door and press the credit switch that the quarter would trigger. Never paid for a game.
Hi, I wonder if the crt tv leaks its high voltage coming from flyback transformer. Is it the flyback itself is damage? or the other component is damage causing the flyback to leak its high voltage? It makes nasty sounds and affects the picture display.
12voltvids if you see this I need your help. I have an HD Samsung Slimfit CRT with extremely complicated video processing circuitry. It has a fault where composite video is in black and white like this one. There is no “jungle chip,” composite video alone runs through four different chips. I tried replacing the main board as a way to shotgun the issue, and as soon as I started the TV for the first time with the new board, I got composite in color. However, after I re-assembled the back cover and then turned it on again, the composite chroma was lost again. It is very strange and I don’t even know where to start.
Sounds like a broken connection in the chroma path. Check the comb filter circuit. That set probably uses a 3d comb filter. I have no experience on any of the Samsung hf crt sets. Mostly Sony and panasonic.
This is a hot chassis. The mini transformer on many sets is for the standby supply to operate the remote control. The horizontal circuit operates on mains voltage. The fly back is used as a power transformer for the different voltages required by the set.
Just so you know, once you connect your ground clip from your scope to the TV chassis your isolation transformer is 100% defeated and doing nothing to protect you because your scope is not isolated or floating. Sounds strange I know but it is do to how neutral is tied to ground at your beaker box. Test it if you don't believe me, you will be able to light a 100 watt light to ground even when powdering your DUT off an IT once that scope ground is clipped to your DUT. I found out the hard way ;)
Bzzzt WRONG.Te ground probe on my scope will earth the chassis, however the line side is still isolated from the AC main. I could short either side of the incoming AC input on the secondary side of the isolation transformer to ground, nothing will happen. Try that without isolation, the neutral side would do nothing but the hot side would have disastrous results.If you can't understand this, I can do a demonstration to prove I am correct.When the device under test is isolated from the AC main, it is isolated, simple as that. That is the purpose for the isolation transformer.I could connect my scope ground to either side of the AC line on the isolation transformer and nothing would happen.Yes I know how the ground is tied to neutral not at the breaker box, but at the utility. Neutral is earthed.Doesn't matter, both the hot and neutral leads on t he isolation transformer are completely isolated from ground. There is NO ground lead on my isolation transformer, no pass through of neutral, or ground. It is a 1:1 transformer. 2 wires to primary, 2 wires to secondary.Completely isolated.
Bzzzt WRONG. Once that non-isolated scope ground is connected to your DUT "or just either leg of your IT" the other leg of your IT now has a high voltage unprotected loop path back through the grounding wire in your scope. Yes, please try this. I know this is how the wiring works in household wiring in the USA so maybe Canada is different but I wouldn't think so right off. I did make a video on this issue many many years ago if you check out my channel. It is a horrible video back when I was using a tape based video recorder and poor editing software. PS: I have a degree in Engineering Physics specalized in electronics so I do fully understand what I'm talking about here in the USA. Please test this so you don't get hurt someday. I love your videos and would hate for them to stop. ;P
Oh Nice, thank you for the quick answere. I have the same Problem by my old CRT TV from 2006. The problem is, that the most people in Germany use modern TVs. For my PS1 I need the old CRT technology. Where I can get new Parts? In an Electronical Store?
Fortunately most of the parts that are going to fail is capacitors, and any electronic component shop should have all the sizes you will ever need. Most common problems on analog TVs is broken solder connections, and capacitors. Occasionally vertical output ICs fail which today may be harder to find.
The isolation transformer only protects me and test equipment from direct AC live current. If I stuck my fingers into the horizontal output circuit then I would get a shock, and I have been jolted thousands of times over the years.When I work around high voltage I keep one hand in my pocket, so that if I make contact there is no path for current across the heart.
12voltvids So that's why we sometimes only see one of your hands. Stupid question: with your hand in your pocket, does that mean the current will go down to your feet or just travel throughout your body?
Rubber soul shoes, so no path to ground. Also isolation transformer, so even if I was earthed I am still protected. The second hand in pocket means that is not touching something else on classis.With the chassis isolated I won't get a shock by touching a live wire and earth, because the isolation transformer isolated the chassis from earth, but it does not isolate the chassis hot from chassis cold.In other words if I was touching say the B+ line, and earth I would not get a shock because the chassis is isolated, but if I touched the B+ and the negative one of the shields on the chassis I would get a shock. So one hand away from the chassis. That way if a shock does occur it is in one hand, no chance of it going up one arm, across the heart, and down the other arm. That is the dangerous part. If I touched + and - by accident with the same hand I will feel it, but it isn't going to kill me. I was jolted on the job my a microwave oven transformer. The tool I was using had an insulation break down when I was measuring HV. 2,100 volts went through my hand, and caused muscle contraction which prevented me from letting go. Other hand in my pocket and rubber soul shoes kept the shock localized in my hand. I jumped back which broke the connection. I did get a nice electrical burn from this, which hurt far worse then the initial shock, and hurt for a few weeks as it healed. Electricity is to be treated with respect.
About retrogaming, I have a Raspberry Pi connected to my CRT TV with a HDMI to VGA converter and with a home made VGA to SCART RGB (picture is amazing) so the CRT is directly driven by what ever resolution I choose, for instance if I go too much out of spec the TV won't sincronize.. I have mine set to 320 x 262 at 60Hz progressive I chose 262 lines (half of NTSC 525 interlaced) so I can have nice scanlines to be as acurate as possible to real hardware. I read that a lot of people set theirs to 240 lines instead of 262, I tried this and though my TV did sync properly the image was more streched (less lines but still filled the screen) but I could actually hear that the horizontal frequency was different, maybe lower as I could hear it better. My question is do you think it is safe to run the CRT in this off spec frequency? Could it damage the set? Or as long as the TV can sync to the signal it won't matter? BTW don't know if it's relevant but this TV can sync to either 50Hz 625 line or 60Hz 525 signals.
Won't hurt it off frequency if it syncs up then you are fine. So you feed RGB directly in. Cool. I have a 21" viewsonic CRT computer monitor,and I have connected my HDMI to VGA adapter into that, and the picture was amazing, and that monitor will do HD. My cheap HDMI to VGA adapter will output either a VGA or component signal. I have used it to record stuff on my component capture card from HDMI sources.I use a raspberry pi as a media player, for SD content into a modulator, but I just use the SD output from the pi itself.
Cool, good to know, yeah we were lucky here in Europe as virtually every CRT since perhaps mid 80's had RGB scart capable connections, most will also sync at 60 Hz even though we use(d) 50 Hz PAL or SECAM. Some, maybe most from mid 90's till the end of the CRT era even support NTSC composite, but even if they don't as long as you feed in RGB it doesn't matter. Scart is very interisting, I don't know if you know much about it as it's virtually non existant out of PAL regions. Apart of feeding RGB directly you must feed in a sync signal and around 3V to the blanking pin to make the TV switch to RGB otherwise it will expect a composite signal and show a black screen. There is also another pin that depending on the voltage it tells the TV if the signal is 16:9 or 4:3, that same pin also serves to make the TV go to AV automatically, like if you were watching a broadcast channel and you would switch on your VCR or DVD player the TV would switch to AV on its own.
I actually have a 14" JCV multi system TV that I paid an absolute fortune for (probably 1,000.00) when I was doing standards conversions as I needed to be able to check PAL and SECAM tapes for clients before sending them out.It has a SCART connector. It was a good investment, as I had a situation once, before I invested in my own gear where I was farming the conversion out to another company. I paid the other company, and they did a shite job, and then I was the one in the crosshairs with my customer demanding a refund. So in the mid 80's my company bought a standards converter, and a multi system VCR and monitor. That way I could show the client the tape, playing in PAL or secam on a native monitor so they could see the tape before it was shipped out. I eventually picked up an AGW1 when the price came down to 3,500.00 as I was busy enough doing standards conversion back in those days. Those machines ran about 12 hours every day. I was so busy out here, as my community has a huge British population, and people were sending tapes back and forth weekly.Many were sending TV shows back and forth!
Man a grand for a 14" TV? That was crazy expensive! Perhaps a future video demonstrating that TV and showing off that SCART socket to fellow North Americans? Time to play with some RGB goodness!
Yes it was ridiculous how much multi system cost in the 80's and 90's.There was one shop that dealt with foreign electronics, and he imported everything in everything, and prices were high back then anyway, and bringing in something from a different market just added to the price. I knew the owner, he actually sold me my very first VCR in 1979. The business is still around, run by his son today. It cost big money to get into standards conversion equipment back then, and that is why we were charging 50.00 a hour to transfer tapes. Some people called up crooks, and a few even threatened never to come back. They all did when they found the competition down at paradise video was charging 80 an hour to do the same thing.Standards conversion machines cost a bloody fortune. I ran with a Hitachi multi system VCR for VHS, a Sony multi system for Beta, and a Canon PAL camera for 8mm. I forget the name of the digital standards converter I used, it was a unit I had. It was not a name brand unit. Rack mount Had BNC in and out and 4 switches on the front. Power, source, input standard PAL/SECAM/NTSC and output format PAL/SECAM/NTSC.It was a fairly big box and weighed about 40 LBs, cost me something like 12,000.00. So a grand for a multi system monitor was nothing compared to the cost of the rest of the equipment. A few years later Panasonic released the AGW1, and even though the quality was not nearly as good it sold for 5G initially, and meny more shops jumped on the bandwagon, and prices fell from 50 an hour to 25 overnight.My equipment had paid for itself, and when I found my competition was offering my customers a discount rate if they would go to him, I dropped my prices to 10 an hour for the remainder of the time I was in the standards conversion business. I still have a multi system VCR (The old Hitachi) and the multi system monitor, and a box that will convert PAL to NTSC, and vise versa. The old gear eventually broke down, and I couldn't fix it. The company that made it was long gone and there were no parts or any data available.It was full of ICs that the tops had been sanded off so nobody knows what they are, or what they do. I made my 12 grand back, and much more, as I was doing this (in addition to working in the repair shop, and running a production business, I did conversion work for 4 retail businesses.)I still do video conversion work from home but nothing like it was back from about 84 though to about 2006. That 22 years I made a good living out of video production, and could justify the sky high prices for equipment.
So would any of that voltage be enough to kill or injure you? I have been bitten by modern automotive ignition systems and they run up near 30 to 40 kv, sometimes more and it will wake you up in a hurry but not kill you, I cant see this TV generating anything like that. I mean automotive ignition systems create enough voltage to jump a 1" gap with a nasty hot spark, I have never seen anything in a TV do that.......
You have never seen the second anode in a TV arc. 30Kv on a cold tube (one that the filament hasn't warmed the gun enough to emit electrons) can pack a hell of a wallop. I got hit by second anode voltage once. My assistant tech had just replaced the CRT on a Sony 25XBR. I was set to do convergence. I reached over the set to adjust the purity magnets. My helper didn't clean dirt off the glass or the cobra (That is what we used to call the HV lead, because the cap made it look like a cobra, and it bites) and when I reached over my forearm came in contact with the cap, and I touched ground with my thumb down at the CRT neck. Sounded like thunder, loud crack. Bolt of lightning went in my forearm, and out my thumb and left an arc mark on my thumb nail that caused a ridge to form on the nail that is there today. Felt like I hit my thumb with a hammer after the throbbing went away. I yelled ever 4 letter word in the book and the boss came in and told me to watch my language and keep my voice down. I told him to F--- off!I don't know which one hurt worse, that one, or the 2,100 volt jolt from a microwave transformer. They both equally hurt.
12voltvids Oh wow! I have worked on tv's but never had the pleasure of getting bitten by one but I have had a modern ignition coil on a car bite me through a rubber glove like it was not even there! High voltage makes non conductive materials conduct like they shouldnt....... Its amazing though, the batteries in your Volt pack more energy then people can imagine, touch one of those orange cables of death and you will be dead and cooked before you realize what happened........
360 volts DC and you won't know what hit you. Yes the batteries in electric cars pack an incredible amount of energy.I wouldn't want to be an electric car mechanic to tell you the truth.
