I miss CRTs. they are resilient and last a very long time. I have a 25" Magnavox from 1994 that was bought brand new for Christmas, its the chassis that has the common cap failure 100uf 100V cap, or something like that. I had to change it once and that's the only thing I did. Still going.... and its a daily watcher in my bedroom. that CRT must have thousands and thousands of hours considering its been on at least 8 to 12 hours a day every day since 1994, Still has a picture on it like it did when it was new. Try having an LCD last that long.
I always trusted the physical installation of the cap polarity over the silk screen on the board. Especially for a unit that is that old. If it was really in there backwards and it mattered the set would have been repaired or scrapped years ago. The silk screen and the printed schematic were always distrusted over what the factory actually assembled. Unless the difference caused a issue. And if it did the issue would have been apparent usually under warranty.
On older Asrock motherboards (~2004-2008), the cap symbols are silkscreened backwards. The polarity markings are right (under the cap), but the filled half circle is the positive side. I've learnt it the hard way, after recapping a board, which was a pain to do with a 50W Weller TCP iron with the old first gen Pb free solder on a 4-8 layer board, and caps that were attached to huge power planes without thermal relief. I had to do it again because I've done it by the symbols, which were backwards... I guess the layout engineer and his mother in Taiwan hiccupped for a while when I realised why the mobo was not working after the first recap. No damage fortunately (except some nerve damage of myself), as the many reverse polarity low-ESR caps tripped the protection on the PSU. It was an old AthlonXP config. I still have the board somewhere I think. *edit* : typos
Well done dave, that will make a perfect old home computer monitor :-D That cap coped really well. It was fed via a resistor and a zenna diode (limited current), a secondary supply to the frame chip perhaps. I know c.r.t sets are very " Old hat " but i still like how good they can be when set up correctly. it's mad that your outside set does not crackle from the anode cap in the damp air lol.
Cap' in the wrong way! Yeah I thought that once as well, bulging cap' and thought by looking at the screen print that it had been installed wrong, put a new one in as per the screen print, switched on and a few minutes later, "BANG" and something shot past my head. Yes, you guessed it, cap' blew up, it was the screen print that was wrong, they just never fixed the screen print. Told my mate about it and he started laughing, then his wife let it be known he was caught out the same way! Should have checked it first and not taken the screen prints word for it. But we live and learn. This was on a 3 amp power supply, so it was quite a bang! It was so loud that people came to see what had happened. here was me sitting with a mile of brown paper type stuff and a mark on the celling and wall where the case had bounced off. I have never seen one explode with such force before, normally it is just a pop, it case flies off and the innards fills the work bench. The Cap was not very cheap either, what is worse I only ordered one so had to wait for another to arrive!
i recall this issue. my parents bought a new rca tv in 1994 and the tv had this issue after a few months use. it would have the vertical issue and then if you messed with the cable jack in the back the coax it would get full screen. one day it go so bad it couldnt be fixed and the picture fully went out and all that was left was sound. tv was bought from silo right at the end of silo's life sadly. the tv didnt last more then maybe a year if even that and the picture was gone. crappy rca thomson junk
@@12voltvids you are right about Thompson, i had a UK Sky + HD box which blew it's PSU, when it was repaired they found it had also fried the HDD, so i let the repairer keep it and swapped it for a Amstrad one, which lasted until I upgraded to one with a 2TB HDD
Dave, You really know your stuff! Great job! I tried fixing the flickering LED display on a Bionaire humidifier. After reflowing the display points on the PCB it worked for about 10 seconds and went out for good. I salvaged the fan in the humidifier and it sucks the solder smoke away from me while soldering now :)
Oh you should have heard me yelling at that damn chisel tip. Bridging everything in sight, haha. I have conical tips and more conical tips. Want more heat? Lay the tip in the work, easy
Dave I have a Panasonic NV-MV40 in which the take up reel arm has been cracked and break into pieces. It is an R4 Mechanism. So,Please solve the problem when you have a vcr that have the same problem.
Hmm. Very interesting to see a cap mounted backwards, especially from a high-reputable brand like Panasonic. Poor quality control when it was manufactured in Mexico perphaps?
Always nice see how quickly you home in on the problem. Brightness limiter, could you explain how it works and why one is needed? TV made in Mexico but the label is printed in the USA!
Brightness limited limits the beam current. Wish I had a schematic handy so I could go through the circuit. I honed in so quickly because I have s seen this problem many times.
Who would of thought such a small transistor would wreak havoc and to have cap put in backwards last 27 years...., it goes to show you things were built better even if there was screwup at the Panasonic factory
Whenever I've put a cap in backwards, it's 'capacitor confetti' time. That cap must have been used for signal coupling and not for keeping a circuit charged. Otherwise, I can't explain it not going kerflewee.
I would think it is running at pretty low voltages. I don't know the history of this tv but i suspect it has been sitting for a long time since it was last used.
When I was about 12 or 13 thereabouts, I would take capacitors out of old 9 volt transistor radios, put them inside model airplanes, and remote detonate them with a Lionel model train transformer. 0 - 28 VAC with a clicks-on resetting thermal breaker. Nobody said young teenagers had wisdom, we all did stupid things. These split top caps just go fizzz or pffft.
What's your opinion on a 1983 vintage RCA CTC-121 chassis TV? (Model VJM2023S) I was given one that appears to have very low hours for the age and came with the remote and manual. She's got a good picture. I still prefer a Trinitron, but this thing still makes a great gaming TV as far as I can tell.
26:00 The cap is in backwards. I never trust the silk screen print on the board as they are sometimes marked wrong. What other verification did you make?
@@12voltvids Personal experience, works for me. My grandfather was a TV radio super repairman, I learned a lot from him. He knew the failure points of all the models. I had a 13 inch RCA color TV I was stumped on, brought it to him and he knew the failure point of that set. Had it diagnosed in 3 minutes. Bad wire wrap connection inside an IF can. Color would pop in and out when you gave it a thump. Experience is the best teacher...... That is why I am watching your videos, I am a technician and retired electronics assemblier I can diagnose to the component level, but lack the type of hands on experience you have on specific technology, ie. CD players, VHS machines. Thanks..
Hi Dave, quick fix well done again. It seems that there is still a slight dark line near the bottom of the screen. Is that a reflection or a latent issue ? JwgK
The pcb looks familiar to me,RCA is non european brand,for sure it is no panasonic also.I think the chassis was released in Greece under the commercial brand as ORION.
@@CotyRiddle Orion isn't Funai, nor are they owned by them. And RCA pretty much only exists as a brand owned by Technicolor SA, where the branding is licensed. For instance, Sony Music owns RCA Records but uses the branding under license from Technicolor.
I was wondering what is the risk of burn in with the lcd/ led TVs made these days? I would like to hook up my old Wi game system to my 2019 LG Nanocell 65”
LCD don't "burn" like plasma, OLED or CRT tubes did where the phosphor actually burns and then leaves a shadow on the screen but they will suffer image retention which can be in some cases permanent. I know there is a warning in my Samsung LED TV manual about image retention and Samsung must be worries because when i put it in mute, the mute icon on the screen fades on and off and moves up and down the screen.
Yes, and once bitten you never forget what it feels like and you don't want to get jolted again. I have been bit twice in my professional career. Both times when I was distracted by a co worker with his endless babble. I still get nightmares of it. Dream of being shocked, and wake up flinging my arms wildly. My wife didn't appreciate that last time it happened as the cat was sleeping on the bed, freaked out and bolted using her for a launch pad.
Television signals are complex and the high voltage with electromagnetic along to the digitized resolution of the scope may display totally wrong signals.And also those years these models were the only affordable with prices around 1000 euro but then was a lot harder to pay 1000 euro than nowadays.Oscilloscopes were equal in price and sometimes more expensive than a standard 27 inch CRT.
Hey 12voltvods, wanted to ask, can you fix pal vcr:s? If u can P L E A S E upload a fixing tutorial vid, kuz i can't fix mine =( (i live in Finland SO i use pal vhs equipment)
A pal VCR is exactly the same as an NTSC VCR except the motor speeds (slower on pal due to the slower frame rate) and the colour circuits. Mechanically they are the same. I have worked on multi system machines but not straight pal as we didn't use pal here.
An interesting video. Nice to learn about. Glad you added a warning about the high voltages.
I miss CRTs. they are resilient and last a very long time. I have a 25" Magnavox from 1994 that was bought brand new for Christmas, its the chassis that has the common cap failure 100uf 100V cap, or something like that. I had to change it once and that's the only thing I did. Still going.... and its a daily watcher in my bedroom. that CRT must have thousands and thousands of hours considering its been on at least 8 to 12 hours a day every day since 1994, Still has a picture on it like it did when it was new. Try having an LCD last that long.
TNX for doing a real TV. Brings back so many memories.
Tom
LFOD !
I have a few "real" tvs in my storage unit. A few Trinitron and a few Toshiba sets.
The knowledge learned helped me
Why wouldn’t ya want a CRT monitor, they’re awesome
Great! I enjoy these educational videos!
Nice vid !!!. CRT vids sure are interesting.
I always trusted the physical installation of the cap polarity over the silk screen on the board. Especially for a unit that is that old. If it was really in there backwards and it mattered the set would have been repaired or scrapped years ago. The silk screen and the printed schematic were always distrusted over what the factory actually assembled. Unless the difference caused a issue. And if it did the issue would have been apparent usually under warranty.
On older Asrock motherboards (~2004-2008), the cap symbols are silkscreened backwards. The polarity markings are right (under the cap), but the filled half circle is the positive side. I've learnt it the hard way, after recapping a board, which was a pain to do with a 50W Weller TCP iron with the old first gen Pb free solder on a 4-8 layer board, and caps that were attached to huge power planes without thermal relief. I had to do it again because I've done it by the symbols, which were backwards... I guess the layout engineer and his mother in Taiwan hiccupped for a while when I realised why the mobo was not working after the first recap. No damage fortunately (except some nerve damage of myself), as the many reverse polarity low-ESR caps tripped the protection on the PSU. It was an old AthlonXP config. I still have the board somewhere I think.
*edit* : typos
Well this one is not a silkscreen error.
Well done dave, that will make a perfect old home computer monitor :-D
That cap coped really well.
It was fed via a resistor and a zenna diode (limited current), a secondary supply to the frame chip perhaps.
I know c.r.t sets are very " Old hat " but i still like how good they can be when set up correctly.
it's mad that your outside set does not crackle from the anode cap in the damp air lol.
The cap is sealed to the glass.
@@12voltvids Water finds a way in, look at your outside cameras, nothing is safe Ha ha :-D
@@zx8401ztv
Only 1 has leaked so far and I suspect that someone turned the hose on it.
Cap' in the wrong way! Yeah I thought that once as well, bulging cap' and thought by looking at the screen print that it had been installed wrong, put a new one in as per the screen print, switched on and a few minutes later, "BANG" and something shot past my head. Yes, you guessed it, cap' blew up, it was the screen print that was wrong, they just never fixed the screen print. Told my mate about it and he started laughing, then his wife let it be known he was caught out the same way! Should have checked it first and not taken the screen prints word for it. But we live and learn. This was on a 3 amp power supply, so it was quite a bang!
It was so loud that people came to see what had happened. here was me sitting with a mile of brown paper type stuff and a mark on the celling and wall where the case had bounced off. I have never seen one explode with such force before, normally it is just a pop, it case flies off and the innards fills the work bench. The Cap was not very cheap either, what is worse I only ordered one so had to wait for another to arrive!
Haha funny story. I wonder how many electronics repair techs wear eye patches.
Pretty clean on the inside, it might not have many running hours.
CRT has 0 lag time, perfect for video games.
I think your repaired CRT display is overscanning on the sides.
No adjustment. Controlled by b+ which is set by regulator.
i recall this issue. my parents bought a new rca tv in 1994 and the tv had this issue after a few months use. it would have the vertical issue and then if you messed with the cable jack in the back the coax it would get full screen. one day it go so bad it couldnt be fixed and the picture fully went out and all that was left was sound. tv was bought from silo right at the end of silo's life sadly. the tv didnt last more then maybe a year if even that and the picture was gone. crappy rca thomson junk
RCA went in the shiter when Thompson took over.
@@12voltvids you are right about Thompson, i had a UK Sky + HD box which blew it's PSU, when it was repaired they found it had also fried the HDD, so i let the repairer keep it and swapped it for a Amstrad one, which lasted until I upgraded to one with a 2TB HDD
Great fix !
Dave, You really know your stuff! Great job! I tried fixing the flickering LED display on a Bionaire humidifier. After reflowing the display points on the PCB it worked for about 10 seconds and went out for good. I salvaged the fan in the humidifier and it sucks the solder smoke away from me while soldering now :)
Oh you should have heard me yelling at that damn chisel tip. Bridging everything in sight, haha. I have conical tips and more conical tips. Want more heat? Lay the tip in the work, easy
Dave I have a Panasonic NV-MV40 in which the take up reel arm has been cracked and break into pieces. It is an R4 Mechanism. So,Please solve the problem when you have a vcr that have the same problem.
Hmm. Very interesting to see a cap mounted backwards, especially from a high-reputable brand like Panasonic. Poor quality control when it was manufactured in Mexico perphaps?
Always nice see how quickly you home in on the problem. Brightness limiter, could you explain how it works and why one is needed? TV made in Mexico but the label is printed in the USA!
Brightness limited limits the beam current. Wish I had a schematic handy so I could go through the circuit. I honed in so quickly because I have s seen this problem many times.
Who would of thought such a small transistor would wreak havoc and to have cap put in backwards last 27 years...., it goes to show you things were built better even if there was screwup at the Panasonic factory
Whenever I've put a cap in backwards, it's 'capacitor confetti' time.
That cap must have been used for signal coupling and not for keeping a circuit charged.
Otherwise, I can't explain it not going kerflewee.
I would think it is running at pretty low voltages. I don't know the history of this tv but i suspect it has been sitting for a long time since it was last used.
When I was about 12 or 13 thereabouts, I would take capacitors out of old 9 volt transistor radios, put them inside model airplanes, and remote detonate them with a Lionel model train transformer. 0 - 28 VAC with a clicks-on resetting thermal breaker. Nobody said young teenagers had wisdom, we all did stupid things. These split top caps just go fizzz or pffft.
What's your opinion on a 1983 vintage RCA CTC-121 chassis TV? (Model VJM2023S)
I was given one that appears to have very low hours for the age and came with the remote and manual.
She's got a good picture. I still prefer a Trinitron, but this thing still makes a great gaming TV as far as I can tell.
The ctc121 wasn't a bad chassis if i remember correctly.
26:00 The cap is in backwards. I never trust the silk screen print on the board as they are sometimes marked wrong. What other verification did you make?
The silkscreen is correct. Have seen this problem many times on this chassis. Same with the open resistor. Very common fault.
@@12voltvids Personal experience, works for me. My grandfather was a TV radio super repairman, I learned a lot from him. He knew the failure points of all the models. I had a 13 inch RCA color TV I was stumped on, brought it to him and he knew the failure point of that set. Had it diagnosed in 3 minutes. Bad wire wrap connection inside an IF can. Color would pop in and out when you gave it a thump.
Experience is the best teacher...... That is why I am watching your videos, I am a technician and retired electronics assemblier I can diagnose to the component level, but lack the type of hands on experience you have on specific technology, ie. CD players, VHS machines. Thanks..
THIS IS WHAT MY TV IS DOING!!! What was the fix? it was just one cap?
Lot of burglary in Canada ? All that security, Chicago area yes.
Hi Dave, quick fix well done again. It seems that there is still a slight dark line near the bottom of the screen. Is that a reflection or a latent issue ? JwgK
Rolling shutter on camera. Had i done this with my CCD camera it wouldn't be aparant.
The pcb looks familiar to me,RCA is non european brand,for sure it is no panasonic also.I think the chassis was released in Greece under the commercial brand as ORION.
Funai corp bought out RCA if I recall correctly (Orion was a funai brand)
@@CotyRiddle Orion isn't Funai, nor are they owned by them.
And RCA pretty much only exists as a brand owned by Technicolor SA, where the branding is licensed. For instance, Sony Music owns RCA Records but uses the branding under license from Technicolor.
@@Watcher3223 do believe funai owned them at one point.
I'm part of the gaming community retro yes
I was wondering what is the risk of burn in with the lcd/ led TVs made these days? I would like to hook up my old Wi game system to my 2019 LG Nanocell 65”
LCD don't "burn" like plasma, OLED or CRT tubes did where the phosphor actually burns and then leaves a shadow on the screen but they will suffer image retention which can be in some cases permanent. I know there is a warning in my Samsung LED TV manual about image retention and Samsung must be worries because when i put it in mute, the mute icon on the screen fades on and off and moves up and down the screen.
@@12voltvids thanks. I’ll probably leave the Wi system for one of my other cheaper TVs
Have you ever ran into the silk screening being wrong? How could you verify if the cap is backwards or the silk screen is wrong?
The focus voltage is +- 4Kv !
Actually it can be as high as 10kv depending on the tube.
Hi is that the correct model number can not find any referance to that model.
What's that thin black line on the screen that showed up later in the video-something to do with scan rate?
Repeat after me. "Rolling shutter"
That's what causes that on CMOS type cameras. Global shutter and frame transfer CCD do not experience this.
Are you Local to the GTA.? Also are you taking on projects.
Other side of the country.
what is with the line across the screen
You are seeing things. No line across screen.
30,000 volts never knew it that high
Yes, and once bitten you never forget what it feels like and you don't want to get jolted again.
I have been bit twice in my professional career. Both times when I was distracted by a co worker with his endless babble. I still get nightmares of it. Dream of being shocked, and wake up flinging my arms wildly. My wife didn't appreciate that last time it happened as the cat was sleeping on the bed, freaked out and bolted using her for a launch pad.
Do you clean up the resolder work after you have finished.
No
Are there any decent & affordable digital oscilloscopes or do you prefer the analog ones?
Television signals are complex and the high voltage with electromagnetic along to the digitized resolution of the scope may display totally wrong signals.And also those years these models were the only affordable with prices around 1000 euro but then was a lot harder to pay 1000 euro than nowadays.Oscilloscopes were equal in price and sometimes more expensive than a standard 27 inch CRT.
A DSO capable for analog TV signals are huge bucks.
@@12voltvids Gotcha thanks
pls help me with sony amp.. pls
THO output 21 Kv , 12 milliamps
Hey 12voltvods, wanted to ask, can you fix pal vcr:s? If u can P L E A S E upload a fixing tutorial vid, kuz i can't fix mine =(
(i live in Finland SO i use pal vhs equipment)
A pal VCR is exactly the same as an NTSC VCR except the motor speeds (slower on pal due to the slower frame rate) and the colour circuits. Mechanically they are the same. I have worked on multi system machines but not straight pal as we didn't use pal here.
@@12voltvids Thank you SO much!!!
=D
That it bad ABL circuit..
1st comment woohoo, Good fix there
Sent an email re: Dual 1010