Fixing a rescued amber CRT

well hello everyone and welcome back to adrian's digital basement 2. we're going to be looking at a crt today and notes not the crt here on the model 2. it's this crt right here i just turned on a studio light hopefully that's a little bit more visible but check out this cute little monitor this was a recent save from e-waste destiny and uh hopefully it works because it's in decent shape and it's pretty cute it's like a little cube this little monitor is very reminiscent of a security camera monitor and very early on with 8-bit computing people were using these types of monitors well specifically with the apple ii because it was a relatively cheap and easy way to get a high resolution monochrome monitor which worked perfectly with the 80 column display on an apple ii there were advertisements showing the apple ii with a monitor like this now it wasn't this particular monitor that was used in those ads i think it was a sanyo monitor on the lower part of the front of the monitor we have the brand name here which is usi and the model number which is the pi 4 so it's like the raspberry pi 4's early cousin this is obviously a flip down cover for the controls and there's a little tab here i don't know if this comes across in the camera but it should be about from there to there and it's snapped off on one side so that's unfortunate but it still does work it's very stiff but the little catch is there which is good we can flip this down and see what's inside well we have a simple set of controls here a power switch contrast brightness vertical hold and horizontal hold there's a little power led here as well but it's actually just above where the door is so when you close it you can still see the power led there on the top of the monitor there is a convenient plastic carry handle which actually offers really nice grip for moving this around on the manufacturer's sticker here it's usi international model number ev-9031a manufacturing date july 1982. and notice here that it is dual input voltage so 120 volts ac but also a 12 volt dc input notice the power difference there 33 watts on ac and only 15 on dc that's because almost surely whatever regulation is happening in this thing for ac sucks up a lot of power probably has waste heat and resistors or whatever so you get a lot more efficiency if you just go right to 12 volts lower down we have the mains input we have the 12 volt dc input and then we have a toggle switch that says display and it has data and picture so i assume that means data or video and then we have a couple controls you can access through the back cover v linearity vertical size and a focus control and then this switch here which is labeled dc restoration off and on is an interesting one dc restoration has to do with the way that on some monitors well actually most black and white monitors the contents of the picture itself affects the overall brightness of the image and i think dc restoration on helps it actually maintain a very consistent brightness all the time no matter what the content is we'll have to test that if this monitor actually works but from my understanding when you have a monitor that does not have a dc restoration function built into its circuit then when you have very little information on the display like say it's mostly black screen then the overall black background actually appear gray but if you have bright objects on the screen it will bring the black level down and i guess for regular television viewing it seems like most black and white tvs i've seen don't seem to do a good job here it just doesn't lend itself well to computer display use though because you end up with that changing brightness which is kind of annoying next up is the impedance switch which has a 75 ohm setting and a high setting you would use the high setting if you want to connect multiple monitors together with the same video output like have one computer and hooked up to three monitors the very last monitor should be set to 75 ohm but all the other ones should be set to high impedance for normal composite signaling the last monitor in the chain or if it's the only monitor should have 75 ohm resistor to ground and most televisions do all all the time but some computer monitors especially ones designed for security camera purposes where you might have multiple chained together you want to do it only on the last one there are two video input jacks here we have a regular rca and we have this very old style coax screw type connector sort of like the the predecessor to bnc and then we have an interesting switch which i've never seen on monitor before it's a polarity switch for normal and inverse so that should flip the picture between a black background and a white background maybe to improve readability in some circumstances on certain machines and then the last control is the horizontal width coil which i notice seems to be broken i'll have to take the back cover off to see what's happening but i might need to use a tool actually like the one i'm using as a pointer here to adjust the width coil while the monitor is running and that's really it for the tour of this monitor before i turn it on though i definitely want to take the cover off and take a look at what's going on inside okay so for the width coil looks like this is actually very similar to one of the tools uh it just has a knob on it and unfortunately the knob seems broken the plastic on the knob is just completely broken so if i snap it off the rest of the way oop there's stickers falling out everywhere here x-ray warning okay no big deal and there is a label for the picture tube type the mi1009h5et so with that broken knob taken off the back i can actually just slide this right out this is what was inside the width coil no big deal because like i said adjustment tools just like this in fact this is the exact one can adjust the width coil without any issue so i'll just rely on sticking a tool like this through the back cover no big deal one thing i like about this design is that there are no vents on the top of the screen actually looks like there's a little bit of a vent inside the handle that just means that dust can't just float into the vents and collect inside the monitor obviously if it's operating it's going to get dusty but it won't really get dusty just sitting there stored all right well i'm kind of excited looking inside of this monitor because it actually looks relatively clean in here i mean there's a little bit of signs of use but overall this thing's in quite nice shape so whenever i have old tvs on the channel that don't have a composite input they're only rf people often say oh you know composite mod the tv to add composite that would make the tv a lot easier to use with computers or anything else avoiding the whole rf and all the static interference that comes with it but the one problem is is most of those little consumer television sets are live chassis and i mentioned that before it just means that they use a very simple voltage regulator to take the mains voltage and lower it down to whatever the tv needs to run all the circuitry well this monitor on the other hand uses a transformer so the mains just goes right into the transformer and probably puts out around 12 volts which is similar to that dc input on the back and that means that this entire chassis is isolated because when you have a transformer like this you have a primary which would be the mains and you have a secondary that would be the output and those are separated from each other they're not touching each other in any way so you are safe to do a composite input on this and you're not going to worry about accidentally sending 120 volts or 240 depending on where you live into your computer through the ground lead and that could easily happen if you have an unpolarized plug and you flip it around or maybe one of your outlets is not wired up correctly that's the danger with live chassis sets that you just don't get with computer monitors so almost always at least all the computer monitors i've ever seen always seem to have a transformer inside that takes the mains voltage and converts it down to a lower voltage and also does that isolation if i took one of those live chassis tvs and i hooked up an isolation transformer to it then i could do a composite mod safely but i don't want to lug around a large transformer just to run that set all the time because if you don't plug that in then you're in danger again so here's the label for the crt and it says cpt i wonder if that's clinton clinton was used in macintoshes and stuff which obviously are a little bit newer than this particular monitor but there's that same part number again in the eia code 577 but like i said this whole thing is actually really clean inside i mean you can see there's a little bit of black coming off of my fingers there but it's not so bad that kind of gives me the impression that this monitor wasn't used a whole lot which just specifically means that the crt should be in good shape because i've talked about this on the channel before just wiping off the glass here so i can get a nice clear look inside i've talked about this before that crts like any vacuum tube because that's what it is really are consumable the emissions from the cathode that go to the crt that light up the phosphor on the front well over time in use the whole thing just gets dim and wears out so the less used monitor has the more likely it is to have a nice bright picture and work well so i've been looking around the monitor for some additional hidden controls and here's one right here there's a sub brightness control and you just have to remove that back cover to get to this these other three controls can be reached while the cover is on anyhow everything inside this monitor looks to be in tip-top shape none of the capacitors have leaked visibly or are bulging everything just looks ready to go so i think uh it's time to power this thing up before i turn this on i'm just going to turn the brightness and the contrast down all the way and i do that in case there's something wrong with say the vertical deflection you'll get a solid line across the screen that could easily burn in the crt and the crt does not appear to have any burn in at all so turning that down is just a little bit of a safety measure of course if you start to see a line you can also kill the power right away but let's turn it on okay i can hear it running that's a good sign we're not going to see any picture of course i have nothing connected and with these controls all the way down let's turn the brightness up it's amber it's an amber crt wow wow wow wow that was very unexpected i was expected that these types of security monitors would always have a white crt because that's typically what you're going to be looking at black and white cameras i'm pretty sure that usi must have taken a normal security camera chassis like this added the amber crt in and then marketed it towards computer users because in 82 when this came out i don't think apple even had their own computer monitor by then or maybe they did the monitor 3 might have been out but amber was all the rage in the early 80s and that they stuck it in here all right well that rolling you see is i don't see that with my own eyes and that's because the oscillator in here is free running right now because there's no signal so it's not running at 60 hertz which is what the camera is currently running at let me plug in an input source so brightness we're still seeing nothing but let's turn these other knobs aha there it is oh a very scratchy potentiometer there very scratchy indeed so i'm definitely seeing some interference on the picture and i don't know if that's coming across all right hopefully that is staying in focus so this is a color signal going into this monitor so of course you're going to see the ntsc dot pattern but there are also these wavy lines that i'm seeing in the patterns like in this white section right here and i wonder what is causing that that's an interesting effect this is the inverse switch so that's kind of cool it's just inverting the cathode drive i assume uh yeah but you can kind of really see those wavy patterns there so maybe those are coming across on the camera okay the next switch is the dc restoration switch so when i turn it on looks like the switch is a little bit dirty makes it all very dark but that might be okay let's turn the brightness up here all right so on these ntsc color bars down here there are these three bars that are down in the black area you should really only be able to see these two but right now you can see all three so that means the brightness is a little too high if you want to turn it down just so you can make out these two which is which i can now all right now here's a bounce signal now what this does is the signal generator alternates between a white field and a black field and you notice when it goes to white you get a little bit of that weird juddering now that's that dc restoration function let me turn this back to off turn the brightness down all right so actually with the function off you'll notice here not only does the picture kind of lose sync and roll a little bit but also the difference between the black and the white is almost the same i mean there's there's a little bit of a difference but it's not much this would not be a problem with a color monitor which has a really good dc restoration function but this dc restoration function should be on to offer a more consistent image and there i just turned it on and even though there's a little bit of a pulse there that's just that circuit's a little slow to respond at least it's working a lot better than when it's off and i can tell you for sure that those monochrome tvs that i've had on the channel do not do a good job at this and if i input this signal into those they would have that problem where the black and the white would look very similarly gray now i have a feeling there's going to be a viewer watching this who has a better explanation than me for what this does and why this is a good thing to have on or maybe why you don't want to have it on and check it out in the comments section i'll pin that comment if i see it all right the width coil does work on a coil like this there's a lot of turns you have to turn it a lot now on a monitor like this you can use the horizontal hole to try to center it it's not ideal because you can sometimes lose sync like like that so you can also use the centering rings on the crt here's that invert switch i just think it's kind of funny but interesting those patterns there's a really high frequency noise that's happening so i wonder where that's coming from i'm going to shut this down and i'm going to power this off 12 volts dc see if those patterns are different at all now you might have noticed earlier that the dc input is actually center negative i was just checking that with the multimeter so make sure you don't hook it up backwards i have no idea if this has any kind of diode protection in it so the mains input is disconnected from the wall there is no switch setting on the back for dc or ac and it is funny that the cable is permanently attached you can't even unplug it but up out of sight of the camera i'm going to turn on the bench supply for 12 volts at 2 amps okay there is no current drop right now but of course the set's off there it comes and on the bench power supply it's drawing about 1.19 or 1.2 amps it's kind of right around what it says like 15 watts or so that's not bad i am seeing this interference pattern on here though so clearly that has nothing to do with like a ground loop or the regulator for the mains voltage input although it's funny because down here it actually is looking perfect now and the interference is only on this top part of the picture now interference patterns like this definitely reek of capacitor issues and it will be on the cathode drive circuit so this is like what's actually driving the picture itself so the signals that come in from the video connector and make its way to the picture tube are processed by circuitry and somewhere in there there is interference now it's weird because it's very high frequency it's much higher frequency than even like the 15 kilohertz that this horizontal sweep is so i'm not sure where that might be coming from but i can tell you for sure that down here it's actually perfect now the interference is only at the top here i'm going to switch to something else besides uh this crosshatch all right and even on the color bars here it's the same thing i know it's inverted right now but the interference starts about midway up this section has it and this section doesn't very odd now there's this switch down here next to the dc input that's between data and picture it's currently set for data and i assume that has to do with like a sharpness setting probably nothing else than that all right yes i can confirm that it is exactly what i said it is it's a sharpness control and on data it's almost like you have the sharpness turned all the way to zero which is good that's how it should be but when you switch the switch over to the picture setting which i assume is video it's gonna sharpen the overall image now what that does is called peaking so when you have a high frequency signal like over here where these lines are very close together it's going to enhance the edges on this section so when i flip the switch it gets much brighter over here but it doesn't affect this side over here at all only effects over here this can help a little bit when you're looking at low resolution video like over rf but it's not ideal you don't really want to add artificial sharpening when you don't need to and even though i've been running the monitor for a little while definitely the interference pattern starts about here it's in this upper section and it hasn't really moved much so i'm going to shut the power supply off and i'm going to switch back to mains and let's just see if it looks any different because it certainly was taking up the entire picture when i had it hooked up on mains okay yes the interference is worse and it's over this lower area as well indicates there are capacitors that probably need to be changed out on this thing well luckily sets like this are really designed for service and the bottom cover just comes right off giving you access to everything you need to check all the capacitors on the main board at least and there are a few more caps on the little uh board on the back here that have the invert switch on it but don't know if that's actually handling any of the cathode stuff the cathode drive it's probably all happening uh here on the main board all right so i figured out some stuff on this crt hopefully you can see the interference pattern on the screen here that i've been talking about and i'm currently powering the monitor off my bench supply and watch this see the interference pattern look it's gone now what exactly am i doing to make it go away or or for instance i can make it come back turn it up there it is it's fully back there i'm adjusting the voltage going into the set now obviously if i'm adjusting the voltage i am currently powering this off the bench supply up there and where the interference goes away is around 11.6 volts or so and i took some measurements actually let me turn this off and turn it around all right so i'll unplug this cable since it's not very long all right so i took some measurements what's happening when you run it off the mains as it goes right through this transformer immediately and then it goes through a bridge rectifier which is on the board there's actually four discrete diodes and it outputs around 14 and some volts and then it goes through a voltage regulator which is right down here there's actually like a little potentiometer for the b plus adjustment and it's a simple bleeder resistor type regulator where there's a large power resistor and it will bleed off any additional voltage to get down to the b plus now if i flip this onto its side here this right here is the voltage regulator for this monitor and that is the potentiometer for the control all right the monitor is plugged into the wall and currently on oh okay well it's doing something else let me um move the camera so this is the other thing it's doing and i know you can't really see what's going on it just looks like a solid screen but it's currently powered off the mains and there's no interference whatsoever and this has happened a couple times where it's just gone away and if i bump the monitor i'm gonna use the back of the screwdriver here just to give it a little bump and the interference is back i have no idea if that interference is showing up on the camera when i'm zoomed this far out but it was completely gone and now it's back so that implies that we have a bad connection somewhere and most likely i would think this is a bad connection on a capacitor the funny thing is is that i've poked around on this monitor like using this stick here and i've poked all the components that are in the voltage regulator circuit and nothing i do seems to make the interference go away it just kind of happens on its own so i'm going to bump the board here on the back yeah nothing there's no effect at all but more than once i've been poking around on here and all of a sudden i look and there's no interference so i actually grabbed the soldering iron and i reflowed everything here in the voltage regulator section i also took the magnifying glass and i inspected for any bad solder joints i am not seeing any on this entire monitor the only thing i'm seeing is that some of the solder joints are kind of crystallized but none of them look like they're not connected and no matter how much poking i do on the board oh wow okay i just poked and now the interference is gone i was sort of poking around in this area i know you can't see where i'm pointing let's poke around a little bit here see if i can get to come back actually i'm going to just stick it in this side here so far it's not come back oh it just came back aha i just found it oh all that poking around and i couldn't find it all right i've locked the focus to manual let's see if i can get the interference to come back by poking the component i think is bad yep i got it okay it's not coming back now let me bump the monitor there we go okay the interference is back hopefully you can see that i'm going to poke the component i think is flaky yep there it is it's gone well there we go enough poking around and i was able to figure it out and it's funny because before i started the camera i poked around quite a bit and i was unsuccessful at figuring it out the faulty component or the one that's causing an issue is this capacitor right here or i think it's that i'm gonna oh yeah just touching it makes the interference come and go so let's take a look at the underside here let's see what cap that is 607 it says 607 it's right here i'm gonna inspect that close up well that is definitely a good solder joint there is no issue whatsoever there so i'm just going to pull that part out and i'll just replace it and before i remove that i forgot to say that i did go over the entire board using the lcr meter here looking for bad caps and every single cap on this whole set tests good nothing looks terrible i realize now in editing i didn't really talk about what this capacitor is doing basically this is the filter cap for the output of the voltage regulator on the b plus and when i say b plus b plus i think stands for battery plus not quite sure actually to be honest but on a monitor b plus is always what powers the entire monitor up it's the main voltage that all other voltages in the monitor are derived from the simple voltage regulator in this monitor bleeder type as i mentioned earlier uses a large power resistor and a transistor a little bit of a feedback circuit basically there's a potentiometer to adjust the voltage b plus on this monitor i think it's around 10.65 volts or thereabouts so the reason why when i had it on the bench supply at 11 and point something volts and there was no more interference is because that entire voltage regulator circuit didn't really need to drop much voltage anymore which meant that the power coming into the monitor from my bench supply which is a nice clean linear supply was pretty much passing through probably some diodes which resulted in some voltage drop and then it would power up the b plus of the monitor when the transistor on the voltage regulator gets involved to start bleeding off voltage it probably is running at a relatively high frequency to do that basically shunting extra voltage through the resistor turning it into heat and that's why we saw that high frequency noise when that cap had a bad connection or whatever is wrong with it basically that interference from that high frequency switching on the regulator would be seen the design of the voltage regulator on this monitor definitely implies that you could power this up like say from a car cigarette lighter to run at 14.2 volts or whatever car normally does and it would still regulate down perfectly down to the 10 point whatever volts that this monitor needs for normal operation and it also explains why running off ac mains is so much more inefficient where it has a much higher current draw all that extra voltage which is coming out of this transformer and the bridge rectifier of around 14 volts and change is all getting bled off as heat running it right at 12 volts is much closer to the b plus so the regulator doesn't have to bleed off nearly as much voltage all right and back to the video all right here's the capacitor this is 220 microfarad 16 volts i mean nothing special it is not leaking as doesn't seem to have any problems and if you've ever tried to use this wick really matters that you buy good stuff the cheap stuff is really hard to use and doesn't work very well not to mention it can get old and not work as well this is uh mg chemical super wick fine braid and i found this stuff works pretty well and i'll come almost out of it i should probably buy quite a bit more of it because it's a good way to get parts in and out of boards nice and easily why don't we give this cap a test just plug this into the meter oh it doesn't quite reach or does it uh there we go i think the connection is not super good 215 micro farad actually it's kind of jumping around a little bit when that happens i have this little gizmo here which uh you plug in to the tester here and then i can clip it on well there we go 210 microfire but that d value is pretty high actually let's see if it changes when i hit the cap no it doesn't really seem to do anything i don't know let me find another cap of a similar value and we'll measure that and see how it looks all right this is the replacement cap i found it's 220 microfarad but 50 volts i couldn't find a 16 volt part this one's made by sanyo so i assume it's not going to be crap it's a little flaky there uh the d is .4.5 so it's way lower i don't remember if i was testing the other cap at uh one kilohertz unfortunately i got to clean this thing because the little contacts there are a little crappy yeah okay so the d is lower but honestly a d of um what was this one point something it's not horrible but touching it was flaky so i don't know if the solder joint was bad like i said i might be able to put this back in and have it work but i might as well just replace it with this one which we know is a little bit better of a cap and let's see if that fixes it well there we have it turning it on it's perfect no interference i'm powered off the main so of course it's dropping about three or four volts across that resistor sorry that's my phone blowing up let me put it face down so it goes into silent mode um yeah poking that capacitor no more interference boom that was it it's fixed now if we turn this monitor over like this one thing that we can see is this cap is very close to this large heatsink here and i think this is probably horizontal deflection there's a big transistor right there this probably gets nice and toasty and it probably just baked that capacitor looking around on the inside of this large heatsink there are no capacitors as close to it as that one was so that's a really good top tip always suspect capacitors that are very close to things that get hot so like the power resistor that's um in this thing for dropping the voltage for the voltage regulator anything near that might be a problem and anything with heat sinks that are this large especially are probably going to get hot and when you have caps that are very close to them suspect that those are faulty now since i could poke that cap and it would go from working and not working it didn't seem to be totally dead and it definitely had capacitance still according to the tester but probably had a bad connection on the inside or i mean it could have been a bad solder joint too i didn't reflow it maybe that would have been a good test before replacing it but whatever i did take it out and it had a high d value so um yeah this cap i'm just going to say it's bad it's funny about what looked like leakage though because there's certainly no evidence of that looking at this side but anyways it's close to that heat sink it gets baked there's also a little electrolytic over here that's also pretty close that one probably should be replaced but monitor definitely is not showing any signs of issue at this point so i'm gonna reassemble this monitor and then i'll give it a little bit of a clean and hook it up to a vintage computer because i know when i have a tv or monitor on here and i don't hook it up to something people always put comments that i should do that so i'll be right back and we're done the monitors back together seems to be working really well and it's looking really nice as well i gave the case a full clean i put some 303 on the black plastic on the front to restore that black luster to the original plastic there was some masking tape that was adhered to the top of this case and also on the side a little bit it was very crusty and hard to get off i don't actually remember if it was on this side or that side anymore because well i cleaned it all off i used goo gone because this is metal and that took it off really easily and i cleaned up the case and it looks quite good i mean it's got scuffs and stuff on it but other than that the case really came back to life let me reboot this apple 2c sitting here and as you can see the beautiful amber glow is visible we're going to load up attack of the petsky robots by david murray you will see in a second that all is not perfect with this monitor there's a little bit of a geometry problem on the left edge here where the picture kind of bows let me uh start the game maybe we can see that a little bit better once the game is running the image overall is incredibly sharp this has no issues whatsoever displaying 80 columns but yeah if you notice there there's a little bit of a bow where this part here is closer to the edge than the top and the bottom i asked my friend frank who knows a lot more about crts than i do if he thinks that this is a problem with electronics inside this monitor or is it something on a deflection yoke perhaps that's not quite right but otherwise i gotta say this monitor is amazing the sharpness is just spectacular on this thing and the only thing that lets it down besides this bowing is along the left edge it's also a little bit less sharp and it's only right here that's less sharp than on the rest of the image now you can control the left and right positioning of course by using this h hold control and i did adjust the centering rings and it seems that the soft focus problem exists on this side of the picture so if you move the picture way over here then this part gets a lot sharper although the boeing doesn't really go away like it's still bowed so i think that might be in the electronics but the sharpness problem which i don't think is going to even come across in the camera is strictly over here on this part of the screen the crt has absolutely no burn in whatsoever which is fantastic it's incredibly sharp as i mentioned and it's very very bright it's probably one of my better amber monitors that actually have in the basement because it seems that amber monitors are extra susceptible to getting burn in and also becoming dim over time maybe the phosphor is just not as reactive as the green and white or there's some other reason i don't really know what it is but like i said all the amber monitors i have have some kind of burn in and they're not very good except for this one now the whole time i've been working on this monitor something struck me about it it seemed so very similar in so many ways to the sanyo monitor that most people use with their apple one and apple ii computers i'm sorry to be recording the screen but this is a second channel video and that's just kind of what i do it's a one camera thing uh the monitor that everyone seems to use with their apple ii and apple 1 machines is the sanyo vm 4509 and if you notice i mean just look at the front here this door the led it's all identical the only difference of course is this um probably white or silver metal badge here that says sanyo and on this monitor it's black and it says usi and pi4 here oh i just noticed this little speck right here which is actually a little chip in the paint it's just exposing the metal behind it so i'm just going to take a sharpie here i'm just going to color that in i know that seems sketchy and crappy but it's actually not a bad tactic there we go i mean there's one over here as well a little just a little scratch that has resulted in a little silver showing through there we go the sharpie can come off if i need to and it just isn't as distracting with a white spot there anyhow not only is this door exactly the same but if we open it up and look at the controls inside take a look at the controls on this monitor versus the controls on the sanyo monitor basically 100 percent identical just to compare here it is again even this little notch right here is the same the little tabs are keep the door closes exactly the same everything about the inside here is the same but wait there's more this is the back of a very similar vintage sanyo monitor and there you can see sanyo model vm 4509 it is also dual power supply with two different wattages it's made in june 1983. it does say made in japan and notice all the text that's right here on this label and here's the back of the usi monitor which is model number ev9031a the text that's written here is basically identical even the formatting of the label is not exactly the same but almost exactly the same just the differences here it says usi international manufactured by taiwan colon company limited made in taiwan and on the sanyo it says manufactured by sanyo electronics corporation made in japan next up look at the controls on the back of the sanyo has a dc restoration switch the impedance switch video in and out notice it's these larger screw type connectors and compare that to the back of this monitor the mains input is off to the side a little bit but it's got that recessed screw has the same switch here and here and here and then this says in and in but almost certainly this is actually just in and out and of course it has one of these screw type ones like the sanyo and then they've replaced this one with a regular rca jack now the little bit of a difference is this is the focus switch over here or focus knob that is and then here and here are the v-linearity and the v-heightener moved over a little bit so probably the circuit board that's actually inside of this monitor is different than the sanyo i'm assuming because of the positioning is slightly different of these controls so really i just found it really fascinating that it's very obvious that there's a shared lineage between this monitor and the sanyo one but clearly they're not identical besides the amber screen even though they're the same vintage so it's almost like maybe sanyo sold their design to colon in taiwan who made this monitor on license or something i just i don't really understand that so if anyone has any background information about what's going on here and why this monitor is almost identical to the sanyo or vice versa i'd love to know more about that so there we have it that is the usi pi4 monitor made by colon out of taiwan and very similar to the sanyo vm 4509 hope you enjoyed the repair of this monitor as well my point with that was it's always a good idea to try to figure out what the fault is with something that you're working on first before just replacing parts randomly in my opinion there's actually a little bit of risk by recapping a monitor for the sake of recapping it because you might put a cap in backwards or put the wrong value in and actually cause damage to the monitor when you have something like an esr meter you can test to see if the caps are within spec or close enough like they are on this monitor so that it's actually going to work fine with all the original caps in here and there was just that one faulty one which needed to be replaced and that fixed it up completely if you enjoyed this video i'd love to hear about it in the comment section below and of course i would love it if you subscribe to this second channel really helps me out it's just very interesting how youtube really promotes channels with a lot of subscribers and the more subs you get uh the more exposure you're gonna get and the more people will see your video so um really that does really help me out also thanks to my patrons their names are scrolling up the side of the screen their support means a lot to me if you want to become a patron yourself you can do so at the link in description below and finally i want to thank the person who gave this monitor to me they saved it from e-waste and of course reuse is always a great thing not to mention saving a cool vintage piece of technology like this which is an awesome little amber screen so thanks very much for watching stay healthy stay safe and i'll see you next time bye

Channel: Adrian's Digital Basement ][

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Id: KrX3s_Dp7kc

Length: 39min 3sec (2343 seconds)

Published: Wed Jan 26 2022