All You Need To Know About CRT TV To Fix Stuff

hi guys welcome to word electronics repair as you know I'm of the opinion that there's lots to be learned about making this old obsolete Electronics so here we have a six inch color TV this is obviously quite old I'm guessing it's probably from the 1980s that's just a guess we have well some presets in there I can see I think there's supposed to be any control knobs on here maybe there should be and they're just all missing but the controls seem to be in there we have audio and video in VCR TV let's do a little antenna Focus controls like there should be something there but it's missing okay this runs from 13.8 volts battery or AC adapter I'm not quite sure why we have two connections there maybe you can charge an external battery from the power so why I don't know earphones yeah quite what the difference between vcr and TV is I'm not sure either but the first thing I do notice or maybe you can hear it there's something rattling around inside there so I'm not going to just plug this in first I'm going to open this up and have a loop to see what is rattling inside here when we do power it up I'll put it onto my bench power supply and we can see what current it's drawing we can also set a current limit as well actually it doesn't specify particularly what the current is but I don't know a couple of amps maybe something like that we can put the limit on so I'll be saying there's no user serviceable parts inside this let's find out shall we looks like there's a couple of screws here I don't see anything else particularly that holds us together but let's remove those two first and let's have a look and see where that gets us as a lot of you guys may know this is the first time I've actually tackled a TV on here of any sort I can't repair the modern flat screens in the workshop I have an agreement with the owner of the shopping center basically which turns out although he said it was to do with you're supposed to have offices on this for the shopping center it's more to do with the fact that somebody else at the bottom end of it was fixing TVs so I don't mind you need a lot of space for TV repair you really do so I've not got into this yet and hopefully this doesn't come into His embargo on TV repair in the workshop this top cover is obviously loose from the rest of them separate from this that panel okay just come off separately probably hold with Clips or something somewhere so if the spongy will help yeah that sounds a bit promising and this fell out of it oh this is just one of the two screws I loosened in the back of it actually seems to be clipped together actually this may not be obsolete junk as such or all that it's probably useful for fixing although absolute junk because I think this would be very good for old games consoles the ones that basically connected to a TV probably handy the ones which have modulators in them UHF because obviously that is analog video come off yeah something happens the batch fell off it and then yes we have it okay well the first thing I noticed is that somebody has a disconnected and soldered the speaker wires but put no insulation tape on that's a good one yeah I don't know why they've done that the antenna connectors also captive effectively but it's also broke at this end so I think we can just undo that screw yeah yeah that was that and the speaker well it's soldered to the board basically this probably wasn't connected put in here just to make it easy to work on but I think for now I will just go with whatever the previous person did and it'll solder this I believe I found what was rattling around inside this is just this seems to be a piece of hard plastic or something or fossilized chewing gum I'm not sure that's what was rattling in there and just looking at this there's more why is here they have been cut and soldered back together again must be some reason for that let's see if we can identify any of the parts of this so obviously this is the cathode ray tube this is the picture tube there's appears to be in touch which is good this is the focus adjustment the high voltage wiring going to you can see okay the board Sitting on Top This appears to be the tuner basically okay there's one more board down there which I can see there's a board across the bottom and there's a board up this side so we have effectively three circuit boards here we have a chip this NEC chip yeah I'm not familiar with what that is this board looks like the tunable the other good reason for that I think this is the antenna connection at the top there yes so we can say this is the tuner this is the receiver okay the one across the top here this is probably the radio receiver tars AM FM VHF UHF vlvation exactly what that one is but those are all on this board so I suspect this is also part of the tuner probably the radio tuner then in that case then the board down the bottom of here this is obviously effectively the TV if you like I can see some components in there with rather strange angles like this capacitor down in there for example yeah and then we have a board down this side here okay so that's what we actually have in this right I think before we start we should have a quick lesson on TV especially CRT TV okay CRT TV for beginners so we have a cathode ray tube this is a vacuum tube and without going really into the details of this I'll explain how the monochrome TVs work and then a bit of information on how the color ones work so cathode ray tube actually rather like a diode has a cathode it has a heater a heating elements also behind the cathode okay and then it has some if you like pieces of mesh which are called grids okay I'll just draw two for now I won't go exactly into this this end of the cathode ray tube this is the front which you can see the picture on okay and this is covered in a phosphor a phosphate is a material that glows when it is struck by electrons with a CRT or cathode ray tube the Rays or electrons are take away from the cathode so basically speaking the cathode when it is heated by the heater behind it it's just a heating filament as emits electrons okay this grid this here is like a wire mesh so the electrons are attracted towards this and the reason being this has a high positive voltage on this okay and this is called the adult just like in the diode cathode because the anode has a high positive voltage the electrons emitted by the cathodes come this way rapidly but the anode is also made of mesh and it has holes in it so a lot of the electrons actually go through okay we'll talk about this bit in a minute they go through and the electrons come across so yeah and this end of the tube has a high voltage connector on it's called the final anode and the tires on a monochrome cathode ray tube maybe hkv to 11 KV something like that depending on the size of the screen so the electrons come with you know okay through here and they hit the phosphate in the middle and they produce a wide dot so we now have a white dot on the screen this grid actually allows you to limit the amount of electrons that are coming through onto the phosphora and the way you do is is by putting a negative voltage on it by putting a negative voltage on here you can effectively limit the amount of electrons that are going to come through because they are repelled by the negative charge on this grannies again it's just a metal mesh because it controls the flow of electrons it controls the brightness okay and this is called the control grid this one by the way this I know is actually called the accelerating R node that's what causes the electrons to speed up and come through this is the final anode as I mentioned and there's actually more than one grids in here generally there's another one we can draw it here and this is the focus grid so that's effectively tightens the beam okay so those effects of what we have in the monochrome tube now all this will do is put a dot in the middle of the screen and you can control the brightness with the control grid so if you put a varying signals here you got very brightness but that's not what I use for TV so what we have around the neck of the CRT are coils okay we have coils and effectively both directions like so and these coils are deflecting coils would be if that's where they go all around the CRT I can show you on ours that's these we can see all the metal coils here okay so by putting a Sawtooth waveform on here we can actually deflect the beam either up or down or left or right and the reason we use a Sawtooth waveform is this Sawtooth is this shape okay so what the Sawtooth will do it will cause the beam to start at one side of the screen for example on the horizontal I want to scan across and when it reaches the other end which is this end of the slope it suddenly goes back down to this voltage and it suddenly flies back it's gonna fly back it comes back to here so by putting a Sawtooth waveform on the horizontal deflecting coils we can cause a line okay so it's not a line backwards and forwards like it scans across and suddenly shoots back scans across and shoulders shoots back so the wide effective way is going in One Direction and then starting again now that isn't quite useful enough for a TV either we need to have lots of lines to make up our picture Okay so on the other coils the vertical deflecting ones we also put a Sawtooth wave but this isn't much whoa a frequency okay this is not the scale the frequency of the vertical deflecting one usually 50 hertz certainly in the UK and the EU probably 60 hertz in the US No Doubt and that will do the same thing it causes the beam to move up and down so basically the beam will start at the top of the screen okay and we will get one line scan so these are nothing like the scale this is at 50 hertz this one is at 16. so I remember this is like 30 40 years ago this one's at 15.625 kilohertz I didn't even look that up I was just gonna do without any remember this okay so for UHF TV what they call 625y the horizontal frequency is this but if you divide one five six two five by 50. you'll find you don't have 625 it's actually 312.5 it's half yeah so during one vertical scanning this is called the frame let's use some terminology now this is called the frame scan and this is called the line scan okay so you'll actually find that during one frame you get 312 and a half lines yeah say 312 lines the other half is when it when the frame flies back from the bottom to the top again yeah and the reason we do this is because when this was designed to get 625 lines at 50 hertz the frequency we need which is over 31 kilohertz wasn't really easily achievable with the technology we had so what it actually does is in the first frame it scans 312 lines actually less a few due to the time it takes to fly back and then it offsets the voltage slightly on the second frame scan so these 312 volts imagine the first ones are here these are your line scans yeah so 312 times during this time we got 312 lines on the screen okay after we get to the bottom of the screen it flies back starts at the top again but these offsets slightly so the next set of scan lines and here okay in between and that is called interlaced and we even see this now with HDMI for example HDTV you get 1080 p and 1080 I and the 1080p is effectively 180 lines per frame Progressive one after the other and the other one is interlaced one in between each other so in this case per frame you have 1080 lines in this case per frame you actually have 540 lines and you do this interleaving or interlacing yeah it's to reduce the frequency it makes it good it was required to create the picture so that is how your TV creates a scan on the screen okay this scan of lines is called a raster now that's not like a guy with dreadlocks yeah it works reggae music this raster is spelled like this okay not the one spelled with the a at the end sounds the same but it's the different word so what do we have now we have a wine scanned across the screen 312 of them they come back to the top and it scans 312 more which are interleaved between the first ones and then back to the first set again so although these Garden related 50 hertz the frame rate is actually 25 Hertz okay it takes two frames to give you the whole 625 lines of the image so that's basically how a monochrome TV works all we need to do now is vary the signal on the control grid to contain the video information and we have a picture we obviously need to synchronize all this together so the circuitry needs to know when the picture starts the first line the second line and so on so we do this using synchronizing pulses so basically between each line of data imagine them so this is your your line scan okay so between each line of data you will have a synchronizing pulse then you'll have your data for all the 312 lines you have another synchronizing poles they have all your data again okay synchronizing pulse that is called a lie sync and after you've scanned all the way to the bottom 312 wires you'll get the frame sync so you get another synchronizing pulse at the end of each frame so you've actually hit in here you've got a sink pulse data sink pulse data sink pulse data obviously not the scale so we get to the end and then we get a frame sink pulse okay that says it's the end of the frame now and then it starts again that's how your black and white TV Works how do we get color out of it so to get core router I think we have three car codes and we have three control grids okay so in the electron God knows it's called this thing we have the three cathodes with the heated elements behind them they have to be hot too with metal electrons okay and each one of these creates emergency we have a control grid here for one for the other one so the other one is three control grids red green or blue okay we have the accelerating anode and we have at the bottom end of the tube the final anode and now on our screen the phosphors are actually dots so the dots basically are well either a grid or like this effectively dots or in some cases vertical stripes like so okay this was Sony 20 trim by the way yeah you've heard that and we need to make sure that the electrons coming from each electron gone each cutout hit only the colored Dotson correspond to that color so these dots themselves will be phosphorus which glow red green blue and the way we make the electron guns hit the correct dots as much for the shadow mask so imagine on the inside of your screen we'll do the verse which is easier we have phosphorus like so or g b r g b we then have a mesh if you like with holes in it which corresponds with the color dots I'm not drawing this very well and we have the electron guns which you displacement each other so this one will always shine through effectively every one two third hole and that the red phosphorus only this one about to use a different color I don't have a green panel I do have a red one somewhere so these don't really correspond but this electron gold will only shine through the one come through these holes and the green one okay on the third chord the electrons only go through the other holes and hit the blue okay so that's how it actually does it a very rubbish diagram but I hope for my description you could actually understand how this works this mesh is actually called a shadow mask okay and there's effectively also acts like it I know this has a high positive voltage on but because of the presence of the Shadow mask a lot of the electrons will hit the shadow mask and not hit the phosphorus screen so to get the same brightness effect with this game as we need a much higher voltage on the HT circuit so don't be surprised to hear that on the final anode Yeah Yeah final arrows the high voltage will be around about 25 kilovolts 25 000 volts this small TV will probably be less than that but it's still going to be a very high voltage I wouldn't be surprised if it was 18 KV or so so the first thing this will tell is that these TVs even the monochrome ones can take in some very high voltages that means at all some hazards involved in repairing these things so that's the first thing you need to know if you're not comfortable with this then I suggest you go find another video to watch okay you can safely work on those equipments you just have to know what you're doing the rest of the TV circuitry wow it's just the receiver that receives the data if you like to put on the screen the picture now with the core TV you don't send three pictures one red one green and one blue you use a bit of trickery to do it and the reason you do that is because when core TV came out it had to be compatible with the existing black and white TV so the actual fact the core TV sends a high resolution monochrome picture there's a black and white TV can also display and it also sends on what's with the sub carrier another frequency it sends core information and it doesn't actually send RGB it sends some mathematical equivalence of those I don't feel like going into them right now if we have some problem with the color on our set we can look at them but if you really want to know about it look for the more Ward color decoder Google that yeah she actually want to know how it does it if we have some problems with that circuit we'll have to look at it what else can we read in this election have TVs work well we know we need a very high voltage to put on the fire now I know 25 000 volts how are we gonna get it well with the Transformer okay so we need a Transformer with a primary on the very odd secondary winding with lots of turns and then we have to use what's called a voltage triplet to increase this again times three and that goes to your final anode for efficiency reasons we want to drive this transform at high frequencies but Luke we've already got a high frequency oscillator driving the coils on here which effectively are also inductors so what we actually do is we use the same Transformer that is driving these coils the line output Transformer and we add a separate secondary riding on the same Transformer that generates the high voltage the final anode voltage so on our TV basically we have a line oscillator this is an oscillator generating 15.625 kilohertz and that is driving this Transformer that's giving us a high voltage and it's also giving us the deflection yeah the line scan huh go into this gun go into the high voltage and we have another oscillator on here called the frame oscillator that's this thing the 50 hertz okay and this is driving another Transformer but now at 50 hertz not at that frequency 15.625 and this one then is driving the scan so this is the frame scan this is the line scan frame so basically all that put together is how a color or a mono grow CRT television actually works yeah I'm interested to hear comments below if I explain that well enough there's quite a bit to take in but I think I hope we did it so first we have a tuner so the tuner is attached to the antenna on this choose in the TV station once we have a signal the signal is split three ways So within the signal we will find video audio and synchronization sync policies okay so these are now sent three different ways we have here our CRT we'll do all this we have the final anode this is your 25 KV high tension okay and in here we have the three cathos with the heating elements okay we have the three control grids one for each color okay we have the focusing anode this has around five KV on it okay and we have the accelerating Arlo which has a similar voltage accelerating I know this is focus this is accelerating our load all right this is the final I know so we need to generate all the signals for this now let's look at what happens to the signals we have coming in so the audio goes into the audio amplifier Audio amp and this goes to the speaker okay obviously the video comes out and this drives these three control grids so the video coming out we have red green and blue three signals these control grids are driven by transistors I'll just drill them roughly so we have and try not to mess this up so I don't have to do it again okay we have three video output transistors okay and these are driven from the signal so let's see if we can draw it red green blue okay and the red signal will drive this one obviously not directly there's a bit of circuit in between okay green will drive this one and the blue will drive the other one so those are our video signals driving the control grids we now have to scan the image so coming out of here we have two synchronizing pulses we have line sink and we have frame sink or if you like vertical sync horizontal sync which is line call them whichever you wish okay so the vertical sync goes into the frame oscillator or vertical oscillator it's called the three okay this runs at 50 hertz this drives via the frame output transistor again some more circuit is involved we could have done it messed up already okay this drives the frame output Transformer so we have a Transformer here f o p t same output Transformer and this is driving the coils around the cathode ray tube that gives the virtual deflection so we'll put a coil here and this is driven by our frame output Transformer that gives the vertical scan 50 times a second now we have the line oscillator horizontal okay horizontal or online and we have the line sink or horizontal sync signal so that synchronizes this and this again drives a transistor this is called the line output transistor okay and this I'm sure I've drawn that on the wrong so it's going to tell we have a message completely up so I'm going to do this one right okay so this drives the line output transforming okay imagine that's like that guys this is just a little diagram okay ground the line output Transformer out opt this again drives the scan tools around the CRT so we have a winding that's driving the scan coils okay we'll put it in purple why not so we have this one this is driving the scan quills that drive the horizontal scan and also on here we have another winding another secondary winding this generates the h t so the HT is the 25 KV to the final element of the tube it's also from the HD derives the 5kv focus so this is HD and focus and all the high voltages that are required on the accelerated anodes from here okay this oscillator runs it fifth I'll do it 15.625 kilohertz so that is basically your TV set line how to put transistor frame output transistor now you need also to power all this circuitry and this is not powered directly from the mains and older TVs you will also have a power supply a early type of switch mode power supply in many cases that would power this circuitry but in later TVs they realized that they didn't have to have a separate power supply because they could put another secondary on the line output Transformer or more than one or the second diary okay so these are all on the same Transformer and this one generates all the supply to the circuitry we'll call it the auxiliary Supply so this basically generates the supply to the frame output to the oscillators and everything else so when the TV first starts up there's a startup circuit that gets us running and once this is running this generates its own power to everything else there was a myth when this first came out in the 80s that you could pull the TV and then once it started you could unplug it from The Maze it would keep on running of course it wouldn't okay this circuit which basically combines or synchronizes the line oscillator the high tension generation the line scan generation and all the auxiliary supplies has a name and it's called cyclops and this stands for synchronous converter which is the power supply part synchronous converts it underline output stage okay now we know what we have just before we look at our TV to see if it's working is it faulty I don't know I haven't plugged this in yet let's just discuss a few things about what usually goes wrong with these TVs so as in most cases whatever is doing the most work usually fails the most often so apart from the usual thing with electrolytic capacitors the common things to fail are the line output transistor this is doing a great deal of work any sort of short circuit on one of the outputs well stop this from working and usually by the transistor as well and maybe the driver stays between the oscillator and the transistor so wide output transistor is a very common failure the wide output Transformer itself tends to Arc over internally and fail this is because of the very high voltages here 25 000 volts okay so those fail frame output fails West often but again it's doing work so it can cathode ray tubes themselves fail what normally happens with these apart from being physically broken is that the cathodes which are emitting the electrons over age will wear out so gradually the emission of electrons gets less and less and you find certain colors are not bright or you lose a certain color another reason we common one is failure in these output stage the video output so it's really the output stages that tend to go wrong if you lose one of these stages 40 40 transistor all sorts like then you'll lose a color or more than one color if you use the frame output you'll lose the vertical scan so you end up with the horizontal line across the screen okay now you may think that if you lose the line output you'll end up with a vertical one on the screen but in fact you won't because if the line output goes the HT goes you've got no HT on the screen on the tube so you have no picture at all those are common failures obviously I think you can see from here if you have a picture that's rolling vertically or sideways if you lose the synchronization the problem is in this synchronizing circuit tune as failing will give you no picture or rather just noise on the screen no signal but that is pretty much a good idea of what goes wrong and don't of course forget the audio amplify It audio output transistors can fail okay so now we have some idea what we've got on our TV let's party let's see what it does or doesn't do so let's see what's happening with this you can just about see my Powers a bar there above the top of the TV okay so I have this set well we'll just put a bit more accurately I have it I have this sector 12 volts okay I've switched the TV on with the button and I've switched it to radio at the moment it's just on radio I've reconnected this speaker I've just extended the white a little bit to make the bits easier so we'll connect this to the power supply I've also set the power supply to a maximum of two amps I've also just noted actually on the TV it is not 12 volts it's 13.8 volts so we'll give it a little bit more power okay let's see what happens so this is set to radio switch on and see what it does well it draws a little bit of currents okay because you expect on the radio I don't hear anything just the volume let's see yeah shooting in volume so let's draw in a bit of power but I don't actually hear anything okay so that's the first problem with this it seems the radio isn't working this is the on off button okay off on service drawing it definitely a little bit of power these are your AM FM and such like let me see well it looks like the buttons are all jammed in actually these are supposed to I kind of like switch between one and the although I'm not sure they are doing okay so there's the first problem the radio isn't working so I guess we have to fix this one first and then look at the TV afterwards I suppose In fairness we could just try the TV instead first okay so we'll switch the power off this is now on TV let's see what it does if it's going to do anything more spectacular it will do it now I am sure well let's just drawing more comments okay nothing spectacular happens I don't say anything on the screen nothing less up so it doesn't seem to do anything in either mode okay you can just see the top corner there nothing happening nothing wet up okay oh something is lit up did you see it on the screen there watch yeah they're a little flash yeah that tells me there's lots of high voltages in here that's the first thing for sure so it's kind of stunning on the TV but shutting down by the looks of it and the radio isn't working let's have a look at the radio first let's see if we can figure that one out I've tried Googling for this TV so this is a sonico okay there is no model number on it there's nothing easy to say anything okay on the top there's nothing there's no model number just tells us controls I have no idea what vlvh is I have figured out these switches are not ganned together so they do operate this one is AM FM this one is the VHF UHF for the TV tuner and this I have absolutely no idea okay vlvh backplate no model number no information so I've tried Google for sonico six inch multi core TV which is what it says on the top cover basically that thing multi-sixes core TV manager and I'm not finding anything I'm finding mainly where's the Sonic the Hedgehog here which in Spanish apparently is sonico so if any of you guys know more about this what it actually is do we have any information out there about it let me know please comments below but I have thought well there's no audio so probably the first thing to test is whether there's any power on the audio amplifier now I think the audio amplifiers on this board for the sole reason that the wires go this way okay the speaker wires but when I just looped on this shape now I didn't just do it by the way that fell over the black wire is broken off so I actually only have one why so the first thing I need to do is figure out where this goes the green wire quite clearly goes down here and I think this might be the headphone socket yeah earphone external speaker this one so I would imagine that the black wire also goes down here somewhere this board looks like it'll come out fairly easily as well so perhaps we can have it awoken figure this one out I don't think it'll be too difficult let's try well I have the board loose it just clipped out of the little plastic holders what we do have is a lot of wires holding this in place I see now why some of these actually unsoldered these why is it so I'm going to get this pulled off there's also one at the back which is holding it which we need to unsolder as well and then hopefully we can wire this board flat and we can actually have a look it's quite clear this thing was effectively put together the circuit boards and all these wires were soldered on by the loops of it okay so let's desolder a few wires and have a look the one that's preventing me from moving this board first is this red one here that's short one okay so that's the first one we'll have to desolder so can we get in at this now well it's these three across the top okay so these have been unsoldered before let's just disconnect them okay and now maybe we can get into this I'm hoping so well it goes to CRT base so this needs to come off now there may have been some high voltage in this but it's been switched off for some time now so I'm thinking it's okay we'll find out okay if you're gonna do this do it with one hand not both just pull the base off the CRT there we go that is a little bit more room I think and I can kind of see down here now not very well but I can't see I don't know how easy this is going to be for you guys to see what I'm doing here I can see the green wire which is kind of like wrapped over these black ones I can see where it goes to and then the black wire obviously goes here as well I'm fairly sure these will just connect across the headphone socket base because if we plug a jet plug in here we should be able to find hopefully the end pin will go to the green and wherever the other part of the jackpot goes I'm guessing that is where the bike wire goes this is really quite hard to record guys because the angle I have it at and I have difficulty to get this board off but I'm hoping I don't actually need to so what I've done is I've pulled a little lead into the Jack socket this is a Stereo One this will be mono I am sure but this will be effectively the ground and this will be the signals to figure out where these wires go we'll go to the ground on here and this is probably ground here I would imagine yeah let's go out here and then the end connected to the audio that one well that's where the green wire isn't it doesn't go there oh it goes here it goes the one next to the green wire now that's probably because this connectors are switching so when you push this lead in the end the audio will go to this pin that's not connected to the green one but I imagine when I unplug this this and this point will connect to each other so let's try it so we have it disconnected and now I think we'll find this end pin which is where the audio was we'll also go to the green yes so the speaker is connected to the right place it's just when you plug this in it disconnects the speaker that's normal enough so the black wire simply goes here okay so I've soldered the black wire back on now let's see if we have any audio maybe the radio is actually working I've connected the wired end to the speaker it's set to radio let's see if this actually works now well we have sound oh and we have radio Okay so radio is working okay so let's see if the TV seems to be running again this is now set to TV [Music] but I'm not getting this flash on the screen anymore I am getting sound while hissing oh and we have a picture yeah obviously there's no TV channels broadcasting but I think if I can actually complete video source of this we might be able to get something recognizable out of it let's try it okay so basically this is functioning it really needs setting up properly she's having a bit of trouble with the vertical hold there it's scrolling it's having a little bit of trouble with the line sync as well talking to the picture sometimes like stretches over there's a whole load of adjustments on here and probably one of these is the wine sink but I have no information with this so I think we've done plenty on this video this is also by the way like a wide screen image it's not 4 3 69 and that may also because it's some problems with the sink so does anybody know what this model is does anybody have any information knowledge if so I'd like to just play around with the settings a little bit the other thing I suspect with this is probably just old capacitors because the thing is basically functioning pretty well I'd like to find a proper 4-3 video source for it I think that might help a little bit as well but yeah it's running that's the thing I've also realized why I had no sound on this I had the wrong read button basically so we do have audio there okay you can see that's the problem with the sink I was mentioning that on fast moving images losing sync almost certainly bad capacities [Music] so I can try to adjust that a little bit [Music] all right yep there we go and this is just wine Terry I'm talking about at the top of the image we have a little bit as well that's a problem with the wine certificate so that way okay although this one's a little bit more work it is basically functioning the flicker by the way has been picked up by the camera it's not on the screen so there we are partially repaired I think to go further with this a I could really do with finding the user manual there's a lot of adjustments on this which are not marked yeah I'm just looking they're not marked on the board I don't have a user manual or rather a repair manual for this maybe somebody can identify this for me and then we can have a play with that it's quite possible because of the age that just some things have gone out of Tolerance and a few adjustments might get the sync working properly the horizontal sink the virtual saying I already knew where to adjust that was that one I have that adjusted correctly I believe but before we do that I'm just interested to know what you guys think of this sort of repair work I mean are you interested in this sort of equipment yeah it's old but I think this is quite useful particularly if you're working on and repairing old vintage home computers and games consoles that had an rfo but you can connect them to this because we'll just put the cable to the aerial basically and tune them in test if that's working sure you could do it with a modern TV but this is quite small although a little bit deep to put on the desk but I quite like this sort of equipment however it was really down to you guys if you want to see more of this sort of repair work I can also do older if you want I can do vacuum tube repair I was trained on that in the early 80s it's a long time since I've done it but I'm sure I would refresh my mind pretty quickly if you want to look at that sort of stuff let me know what you'd like to see on the channel is the basic question really in the comments below hope you enjoyed that if we do bring this out again I think the first thing I will do is replace a lot of the capacitors which will mean removing these boards but I think that'll also help a lot with this it's just a big job because basically the only way to do it is to unsold all the wires are attached to it pretty much make a note of where they go replace all the capacitors and stick them back on again it's not easy to work on this sort of stuff that is for sure I hope you enjoyed that anyway that was a quick beginners 101 in cathode ray tube TV repair at least if anything you've come away with an understanding of how these things work interesting again I found something at the car boot sale that basically works yeah but it was an interesting tool to learn from okay so regards of whether you're really interested in this sort of stuff or not I hope to see you again soon on another learning electronics repair video where I no doubt we'll be doing something completely different okay guys so until next time adios amigos

Channel: Learn Electronics Repair

Views: 19,134

Keywords: learn electronics repair, learn electronic repair, electronic repair, school, lessons, course, training, free, fault diagnosis, trouble shooting, troubleshooting, pcb repair, component level repair, tv repair, vintage tv erpair, retro tv repair, crt tv repair, how crt tv works

Id: aWVE3z1ZRtg

Length: 55min 43sec (3343 seconds)

Published: Sun May 14 2023