 Hey everybody welcome back today to Retro Tech and you know it's a new year here in 2021 and I always like to take this time to kind of reflect on things I have done in the past year and maybe see if there's some things I can improve and one of the things I was thinking about is what can I do to actually maybe make my videos here a little bit more helpful and kind of the next level that has been you know festering in the back of my mind for probably the last I don't know six months or so has actually been more on the side of troubleshooting. So if you've been watching my channel for any length of time you notice a lot of my videos will have more of an approach to repair on these machines. A lot of times we're going in and we're just repairing and replacing tons of parts or swapping out parts if we're conveniently fortunate to have a replacement part but what if we don't have that option or what if we really need to figure out what's causing the exact issue. Today I'm going to do a first step towards that new goal and we're going to have a video where we're going to do some troubleshooting and we're going to try to figure out what is causing a specific PVM it's 8041Q to not have the red color on the screen and so to do that all you need really is some kind of a meter this is nothing special as long as it reads DC voltage and continuity which most of them will but the other thing is is this is a tube that we're you know dissecting and looking at this is an 8 inch tube and most of the Sony PVM 8 inch versions but again we're going to look at how to figure out what's causing the color loss is it a board issue or is it a tube issue or is it a cold solder joint or maybe a component problem that's what we're going to get into today so without any more introduction thanks again for joining me and let's get right into the repair. All right everyone here we've got a Sony PVM 8041Q that's been brought to the shop to get looked at I'll go through kind of what's going on with it so this one was bought off eBay by somebody locally for $70 and that included shipping but it didn't really power on from AC we'll go through and show you that test here in a second and then we're going to try some other tests and just see what actually needs to be done here the first thing again is we're going to try and power this on but I did want to show you kind of a rigging that the owner had done to get power into the monitor to test it just to see if it would even work and what I want you to notice down here is this DC voltage there's some cork in there to separate the two lines and just isolate them and that actually plugs into it looks to be an old maybe power supply for something like your computer and this one outputs 12 volts DC 5 amps max 60 watts so you could use this to convert your power to DC to power the monitor which this is kind of this almost the same process that this is doing internally when you hook up an AC plug so first let's start by just trying to put in the AC power even though I doubt it's going to do anything we'll see initially if we get any kind of response here so it's obviously plugged in I am getting some kind of noise which is interesting so there's some kind of reaction in that power supply but it's not it's not transmitting into actual stable power on the screen all right let's turn that off unplug it now let's try the homemade DC power supply it's using the same exact plug and then now let's see and it sounds like it's normally powering up the power lights on I'm going to go ahead now it's and stick a video signal into input one and we'll see if we can get anything to pop up all right so I was finally able to just get it to sync up and what it looks like is we don't have any red color right now just to confirm that I'm going to go to the 240p test suite and I'm going to pull up color bars and there's green white and blue and our red is missing either the red color gun is out on the tube or we have a solder joint problem on the color board which is the board on this side so at least we know that it does power on and I've got a replacement AC power supply that we're going to swap into this what I don't know though is if the red color gun is out or if it's from a cold solder joint on the color processing board now I'm just going to remove the shell I believe that we should be able to check a couple points maybe to see if red is coming and going when it's supposed to be going into the tube maybe we can check to see if we're getting any voltage on this pin connector down here if we are then we know the reds still being sent the signal is being sent to the tube it's just not producing an image but if there's no signal no voltage on that line then maybe that means that there's an interruption in the circuit for the red color so my plan is to maybe turn this thing on and connect a ground point and a red point see if we have any voltage reading on there now it's time to run some tests and again the very last point before it goes from the color processing board into the actual neck board is right along the side here you can actually follow where it's connecting based on the cable now it does appear that you know the solder on the red line does not look the best but it also doesn't look like it's breaking any continuity we'll check that after we can power it back off what i'm going to do is i've got my meter set to voltage on dc and there's not actually a ground pin there's a bunch of other pins again this is live electricity so we want to be very careful but what i'm going to do is i'm going to probe with my positive on the red and then i'm going to just use the actual frame as my negative or my ground i'm sorry not my negative of my ground for my negative probe and i'm getting 72 plus a half a volt around in there 72 and a half volts and i'm going to take it off the red now and the green is a couple down be very careful when you probe you don't want to short anything out incorrectly but it's kind of close to that it's a little bit lower on the voltage 74 and the bottom pin is blue let's try that one 77 so what that means is the colors being generated all the way up to this point we can run the same test to see if we're going to have continuity we can check continuity between our red point here and our red point on the back of the tube and that would be a little bit safer with our power off what i'm going to do now is check the continuity between these two points by turning it off unplugging everything and now we can check our continuity between these two points so we'll change our meter over to just measure continuity and then we'll measure the continuity between blue green and red so the red ones down here on the far end we'll just so we're definitely getting our current there let's try green is that one and this one and then blue finally let's try it okay so blue's gone through there too see check a couple spots and make sure we still got continuity along that red line inside of here on the actual board which appears we do so i don't see any obvious spots on the board with the solder being bad so we're going to do is we're going to take some parts now from another salvaged 8040 including the power supply and the tube and we'll swap those out and hopefully just hooking that up will cause the color to come back because again we're getting current into the tube and it's supposed to be showing red but it's not so you know a little troubleshooting i mean hopefully it means that we're we're on the right track now before i go in and switch out the tube and the deflection yoke and fly back i'd like to try one thing i've got my new replacement power supply here so it would be nice to go ahead and install this in place of this old one and then we can test that power supply make sure it powers on and still see if the tube shows only you know green and blue which it should that shouldn't have changed it not the power supply so we can but we can at least test the power supply but at the same time i want to change out this neck board because that could have either a cold solder joint on it or the resistor on the red line could actually have failed and that could be the reason that there's no red current going through there so the easiest thing is to take and use the parts again from that 8040 and it's the same board back here now obviously the the design is slightly different just the actual look of the board but it's the same build out same set up and everything and even the part numbers on it match just to go ahead and start on doing some of these things on this current neck board here you can just pop off these from the back of the fly back which control the convergence and focus just wiggle that a little bit and pull the neck board out and off and all of these same connection cables will plug into either one of these for our test first thing i want to do is test the power so that's plugged in through the ac power supply and we have normal power up now let's turn on our console and see if we have any let's see so no the red color is still out on there so it's not the neck board there's no problem with this neck board and there's no problem with our other neck board it looks like so still looking at a tube swap on here but the power supply switch is working and that's good we just need to get that other tube in here i'm about ready to swap the tube out but i wanted to show you something that this one is not like the other eight series where it actually has a anode cap that is similar to all the others that can just be popped off on its own and it doesn't actually need to have the whole setup back here changed out so we can just change the tube and the yoke and that can come from another monitor that either is the same or you can cut the other assembly off if you don't need it from your eight zero spare monitor and this one also accepts the same tube from like the eight zero two zero which is a different older monitor but it has the same just ring anode same build out for the crt so it's a good substitute i've removed our bezel and now what i need to do is just get these four nuts off these bolts i can't usually get them started with your hand but they usually just take a small crank and they are pretty loose so don't over tighten them you just don't want to you don't want to basically slightly hand they're going to be slightly hand tightened so we're going to reconnect our cap to plug in the rest of the neck board we also need to plug in this so let's get that done well here we go the only thing disconnected is the tally light so let's just hope for the best power and everything that's coming on the screen boom yes red green blue that was it our troubleshooting was right and it was the tube the red gun was out on it now i've seen that happen before i'm not sure what it is about the red specifically that goes out but that seems to be the most common color i see out on tubes is red i'm working on calibrating my screen everything's going good so i am seeing some purity problem in this corner up here let's go to a solid screen so we're going to try to degauss this it's a little bit better still shouldn't so now that i've got that still there i can try and remove some of these convergent strips in that corner there are quite a few and then i could try to introduce a magnet to the back sometimes there are those so that might work and so i'm going to have to work on that for a little bit to see if i can get that hue to come back to red all right so we're pretty well ready to finish up on this little monitor it just needs a little cleaning and then we can put it back together but what i want to do is just go through one last look at the 240p test suite you notice i did get rid of a lot of that purity issue on the side by adding a purity magnet so behind here against the yoke i just epoxy to end well not epoxy i use i use this for some of these instances this is black rtv silicone that's what i what i use to secure that little magnet in case it needs to be removed or moved sometimes it's hard to tell when you put a new tube in it can take a few cycles and hours to get its purity completely settled but that looks big enough to make an adjustment and add that magnet and that's not unusual to have at least one sometimes two purity magnets on these tubes even the smaller ones pretty much eliminated all the purity issues that were over here on this side that just took some extra degausing and this is one day later after the installation of that purity magnet and so it seems to have corrected the tube let's check red which was the worst looks pretty uniform red to me green looks great blue too now that i've finished up with the hardware repairs and adjustments i like to go through and check the calibration screens one last time to make sure that no more adjustments need to be made in order to get this to the client or owner now we'll go through some details on this specific model for you in case you're unfamiliar with the sony pvm 8041 q sony list this is a fine pitch eight inch trinitron color monitor it doesn't feature 250 tv lines and a comb filter for ntsc now again this video monitor does only support 240p and 480i as far as video resolutions there are built-in inputs for composite s video and then a component video input that can be switched to rgb with sync processing available and it also does offer sync on green if that is needed it does support ntsc c cam pal and other formats for video and it weighs almost 18 pounds it does offer a flexible option for powering itself i mean there's a battery input it also accepts 12 volt dc power and standard ac power and then that's multi regional too so there's a lot of swings between whether it can go down to 100 volts all the way up to 240 volts if you are in a different power region it's a great test monitor to use in your lab or even as a side-by-side monitor for a larger 13 to 20 inch pvm this is still a very portable pvm too so if you need to move around with one this is a good one to use and for the remainder of today's video i've got a slideshow that shows you the donor pvm i used for the tube this is not the power supply pvm that came from a 8040 but the tube did come from an older monitor which is the 8221 and that one is from the late 80s and early 90s and it only processes composite video it does have external sync processing but really nothing else and so it's a great parts monitor in case you do need a tube because the tube matches the tube in 8041 q series so if you do need a tube don't just think that you have to get an 804 to fit in this monitor you can get one of these 8220s or 8221s there's a lot of pvms that use this same small eight to nine inch trinitron tube in them but that's going to do it for today's video i really appreciate you joining me and if you're interested in maybe getting a crt repair of your own and what more information on that please do check out the links in the description of this video i do have a lot more coming in 2021 so make sure you subscribe and stick with the channel i appreciate you and have a wonderful day i'll see you guys next time with some more retro content