Improve your C64's video output with this simple fix

well hello everyone and welcome back to Adrienne's digital basement first off a little housekeeping I want to point out something that I do on a lot of my videos that people may not be aware of when I have long videos with lots of different sections in them to make it easier for people to jump right to the part that they're interested in I always put in the description some links that jump directly to those sections that way if you've come to this video sometime in the future for instance and you want to figure out how to do something specific that I cover in this rather long video you can just quickly jump right to that section also on a lot of my videos there are often many comments that come out that are very similar and instead of me answering a lot of them what I'll do is I'll answer a bunch of them in a pin the comment so I just ask that if you have a question and you're gonna put it in a comment just quickly check to see if there's a pinned comment that I've put where I might already have answered your question all right now let's get right to it [Music] so here's my zip 64 I think everyone's pretty familiar with this machine let's just pop the cover off this is the machine I showed last time where I had temporarily installed the RF bypass board will have installed it in a more permanent fashion now but I will get to that in a section first I want to talk about this board itself so since posting the last video I haven't really been able to figure out exactly where this board comes from meaning I don't know who made it and I can't tell you where you can buy one for yourself now from a functionality standpoint this board does work quite well although it's not perfect so what we're looking at here is a checkerboard pattern of white and black pixels and I've output this through the luma chroma to my retro tank 2x but even on a CRT monitor like a Commodore 1084 is the same thing there's this interference rainbow pattern that is moving back and forth across these pixels and when you look just statically at it it's not terrible but if you move your eyes like this across the picture you do see this rainbow pattern now I've done a little reverse engineering of this board to try to figure out what the problem is and it turns out the way it generates composite video by combining chroma and luma isn't such a great design and it's back feeding the luma signal into the chroma signal and when you're displaying a pattern that's one by one checkerboard like I am there that actually creates a phantom chroma signal that's why we're seeing those rainbow patterns the fix for this is actually to remove a capacitor that couples the chroma signal to the luma signal and that eliminates that back feeding the negative aspect of this of course isn't the composite output is now monochrome but it makes the s-video output look perfect I also noticed when looking at the chroma signal on the output of the Vic to some of the luma signals actually leaking through there as well so 150 picofarad capacitor to ground on the base side of the chroma signal seems to eliminate a lot of that as well the result is a nice perfect checkerboard pattern on this video with no rainbow patterns at all alright next up let's talk about this little board that this is now mounted on originally I just had this stuck right down onto the counter 64 main board which was fine it had no issues it worked fine just like that the only issue is it left two empty holes here at the back of the case this is the board I have it mounted to this is an open source project which is a Commodore 64 RF modulator replacement it's very similar to what's going on right here with this little yellow board but it's larger and it's designed to be mounted right onto the motherboard but it's extra cool features are an RCA jack here and a headphone jack this is for outputting composite video directly without a special cable and the audio jack of course is for hooking up speakers without needing a cable so you can hear the audio I had built up one of these boards and it does work fine if you have no-armed modulator in your machine or it's totally bad getting one of these will work for you the picture quality is not perfect I had some slight smearing on the output but in the end I don't think using one of these is really worth it because the mods I'm going to show you in a little bit with the built-in RF modulator basically do everything that this does except for the headphone output but it did provide a nice base for this board that way I could just solder it directly onto this board this composite output does work properly as does the audio output the audio output comes in from this pin just goes straight to here I have jumpers now for the luma and chroma so I can actually inject that directly into this board if I'm doing some testing or whatnot it holds these two jacks in the correct spot so they're exiting the case just well perfectly and for my test machine specifically I'm actually finding it very helpful to be able to take just a standard RCA jack and connect that right up to the where the RF modulator RF output would be originally just to get a quick picture this is great for testing if I can't find my little pigtail adapters which I use for hooking up the 64 to a monitor normally so a few people had pointed me towards this article which I had actually already seen about improving the video quality on the Commodore 64 this person posted back in 2016 that this little fix would improve the video quality you could do without removing the modulator there referencing one of the two schematics that are floating around on the internet for the RF modulators and they're saying that you cut this resistor here looking at a picture it's actually just lifted right here so they did do exactly what they said but this particular mod will actually do absolutely nothing to improve the video quality of the composite or s-video output under 64 and the reason why cutting this resistor will have no effect is pretty simple to see it will disable the RF output and that is that so much is true but if we follow the trace back this is the emitter of a NPN transistor this is designed to buffer the luma signal for the RF modulator portion itself the composite and luma output is fed off its own dedicated NPN transistor these two diodes isolate these two transistors from each other so anything that happens on this lower transistor on this RF stage is completely separate from this upper part which is what's generating the chroma and the luma that's the funny looking at the comments here this one guys says it improves the picture very little just a little more clean well I'm sorry that's not even possible those two video outputs are totally separated cutting that resistor will not have an effect so for the real reason for me to remove the RF modulator and install this buffer board on this revision of mother port was to figure out if indeed all of the blurry problems were due to the RF modulator itself and nothing on the motherboard that we need to fix and as you saw in part one definitely it's the RF modulator that's causing the blurriness and no other component of the machine okay I've waffled on long enough about this this is an original 250 407 comodore 64 unmodified and when I first set out on this project I wanted to be able to take a board like this and with very simple tools which means anyone can do it modify the RF modulator to produce video output that was as good as any of those replacement PCBs for the arc modulator like the one I have on my other machine and I feel I was successful in that endeavor now before we do the mods I need to talk about first the different revisions of RF modulators that you'll find on different commodore 64's so I created a little matrix in Google sheets and I have columns for a long board or short board the board assembly number itself and then the RF modulator that's installed in the board now you'll notice I have columns for NTSC and PAL and that's because with the same revision motherboard like 250 407 which is the one I was just showing there's different modulator on a depending on power NTSC it's possible there are others for different regions of the world as well like maybe in Japan there is a different NTSC one than this if you take a look at the edge of the are modular there is a model numbers sticker on here or there should be so you'll be able to tell based on this matrix if the modulator that I'm showing you how to mod is the same as the one that's on your board now color coded the different modulator types the yellow ones here are very blurry and these are found on the 250 407 s and on the kayuu boards which as far as I understand are only available in the PAL regions I'm not going to be talking about the original revision of motherboard the one that has 5 pin video only and then on the later long boards the NTSC ones have this mdavey a 3405 I have these motherboards with these RF modulators here so I could make the mods to it to improve the video quality and make sure that validly works but I don't have any pal boards so I'm actually not even sure if this is the right part number on there I just assumed because the NTSC one is 3403 230 405 that they follow that same convention 3603 230 605 can you please let me know in the comments section though if this is wrong and until I get my hands on one of these pal modulators I won't know for sure if there's any issues but down below here you'll see I broke down the actual issues with the modulars that I know about so the PAL md6 Yui 3603 it has blurry luma and composite video output the color output though is fine so the only mods we have to make are to improve the blurry luma and composite on the NTSC version of the modulator that a30403 it has the same blurry composite and luma as the PAL version but it adds an extra bit of color smearing but luckily we can fix both of those on the NTSC one moving on to the VA 3405 this is the NTSC one found on these later longboard revisions it has very sharp luma video that doesn't require any fixing but it has the same color smearing issues as the NTSC version of the modulator right here and luckily it is fixable with the PAL one since I don't have it I'm going to assume that it's similar to the difference between the two NTSC modulators which will likely mean that it has very sharp video output and it doesn't require any fixing at all now for short boards it's out of the scope of this video but I will say one thing I own one short board and it's actually a pal board but I've converted to NTSC so it has the PAL modulator on it and actually outputs perfectly nice-looking video with no issues that I can tell so I don't think really any fixes or require for any of the short boards to recap I'm gonna be showing you how to fix these modulator z' here in yellow and also fix these ones in green this is one of the module leaders off the 250 407 boards and as you can see it looks a little bit more complicated than the modulator that's on these later revision long boards now from a complexity standpoint they're actually the same it's just that the older modulator only has traces on the bottom while the newer modulator has actually removed most of the components from the top side and made them surface mount on the bottom my goal in figuring out the mods due to these modulars was such that I wanted a novice to be able to do the mods themselves with simple hand tools and without needing to desolder these from the main boards due to the difficulty of doing that without special D soldering tools so really the next step to figure out what's causing the blurriness in this modulator is to understand how the modulator works normally you would just take a look at the schematics to figure out how the circuit is designed and what might be the problem but unfortunately there does not seem to be any published schematics for the NTSC modulator on these revisions of motherboards there are two schematics for RF modulators floating around on the internet right now one of them is for the PAL version of this exact modulator although one of the issues with it is as such a low-quality scan that is impossible to read the component values to really know what's going on the other schematic I found was for this RF modulator right here the NTSC version that comes on the later longboards and I've printed out the little relevant section right here that has to do with the inputs from the Vic - and the outputs to the din connector on the machine and the reason why I know this is for NTSC is because this has an inductor right here on the color input which is that inductor right there that is not going to be you on the pal version of the modulator so as how I know that this schematic is specific to the NTSC version so what I went ahead and did is I created schematics of the relevant video in out sections for both the NTSC and the PAL RF modulators for this 250 407 motherboard that allows me to fully understand how this modulator works and what I need Ahmad to fix the video quality issues first let's start on the NTSC version that's V a30403 the luma input comes in from the Vic 2 and immediately splits it goes through two diodes which isolate these two stages from each other the first top section is essentially a dedicated NPN transistor that goes to the luma output on the din connector let's go through exactly what's happening so the diode allows the signal to come through it hits this Junction here the reason for the resistor above the MPM transistor is the base has to be a higher voltage than the emitter so this brings down some voltage from VCC to allow that then there is a capacitor that goes to ground and when you have a capacitor like this to ground that's actually creating a low-pass filter that means that it's allowing lower frequencies through and filtering out the high frequencies this goes to the base on the transistor which is basically turning off and on the transistor allowing this VCC to kind of flow through and then it's coming out of the emitter which is pin 3 and it goes through a voltage divider there and it outputs the connector so the only possible thing on this entire stage that is filtering is this capacitor so I wrote to improve the luma sharpness you cut c1 now on the NTSC modulators there's a separate diode and transistor that is specifically for the composite and the RF circuitry now I didn't reverse engineer the RF circuitry because I was didn't care about it I thought was irrelevant in this situation but essentially you notice this looks the same up until this point here and what's happening is this also has a capacitor I've labeled it c2 and that's also filtering the high frequency signals out of the composite so I wrote here to improve composite sharpness cut here it comes out of the emitter of the transistor goes through there is another capacitor to ground which might possibly be filtering the signal there's two different voltage dividers here as the signal splits one of them goes to the RF circuitry r14 is that resistor that that guy cut in that other post I talked about earlier and on the composite it just goes straight out the composite now you'll see a couple wires coming from down below and what this is is this is the chroma circuit and this is how it feeds the chroma and mixes it in with the composite video because remember composite is the chroma and the luma mixed together that's what's happening here with these two capacitors and this is happening separately with the RF and the composite now it is possible theoretically that if you cut this r14 resistor to the RF circuitry on the NTSC version of the RF modulator that it might somehow improve the video quality but actually did that as a test and it has no effect whatsoever r14 is a very high value resistor as the RF circuitry requires a very low current of a video signal this is compared to composite that when you plug in a monitor there's a 75 ohm load on this connection which is very significant compared to this barely any load up on the RF side so cutting this has basically no effect but back to these two capacitors on the composite line I found cutting c2 does improve the sharpness of the composite although if you don't care about touching the composite and you only want to improve the sharpness on the luma which is the s-video connection you only need to cut c1 down here on the chroma section there's a little bit more going on because it's a little bit more of a complicated filter that's happening this inductor though is what I found to cause the color smearing I will show you what that looks like in a second in it's very minor but if you do remove this it seems to have no ill effects whatsoever except for removing the color smearing I'm not quite sure why it was put there in the first place perhaps someone who's an analog video expert could let me know but I definitely found that removing this inductor or jumping it just which takes it out of circuit eliminates the color smearing there is a capacitor to ground that's c4 and it looks similar to the one that's going to the base on the luma up above but I did find that if you cut this it has some ill effects of actually creating that rainbow noise effect that I showed you earlier in this video on that little orange bypass board it lacks in this capacitor which results in that rainbow interference pattern if you cut this on the stock RF modulator that interference pattern is seen as well so really on the color stage of the NTSC one the only thing you want to do is jump out this inductor for maximum video quality there's one more thing that needs to be done on the NTSC one and it has to do with the power supply that's inside the modulator it uses a simple Zener diode to create a power supply but unfortunately this does not have any capacitors added to it which is a bad design practice and looking on the oscilloscope I could see that the power rail was quite noisy which actually resulted in a good amount of noise in the video signal as well the luma signal specifically Zener diodes when they're used in this configuration should have some capacitance added to them in parallel to ground and that's not done at all on this so I found that adding 100 nano farad directly on top of the Zener and you can do this from the top of the board cleans up the power supply dramatically ok let's start with this very stock an unmodified 250 407 main board what you're gonna need at the minimum to do this mod are some cutters like this these are very cheap clones of these from China you can buy these in multi packs from amazon or ebay or wherever you need something that has a nice sharp tip that you get in there between the small components and clipped legs if you want to remove the color smearing you're gonna need a soldering iron because we're going to need to jump over the inductor and I'll use this little piece of wire here which I've already pre bent to do the inductor jump there's a final mod which I didn't mention and that is connecting the composite output of the modulator directly to the RCA jack that's on here so that disables the RF obviously and allows us to plug a video cable into it just like I showed you on my zip board and to accomplish that you're gonna need a little section of wire I mean I have this piece here which is a shielded piece it doesn't need to be a wire like this it can be something as simple as this bodge wire as long as it can make its way from over here to over here it's good enough ok before we get started with the mods let's take a look at the color blue and the sharpness and just like we saw in part one the text is very blurry but especially between the risers like on the M there and the E but also the color bleed which is really apparent along the edge here now when you sharpen the video quality by cutting the filter resistors it actually makes the color bleed more visible because the luma is now much sharper to really illustrate the color bleed and the fix first will sharpen the video so you can see the color bleed a little better and then we'll fix that and you'll see the big improvement that you get from that mod so we have two capacitors to cut we have C 1 and we have C 2 it doesn't matter which side of the capacitor you cut it on as long as you're isolating this trace up here from ground so the two capacitors we're dealing with is this one right here so the one I'm bending back and forth and also this capacitor right here that I'm bending back and forth the way you disable these is up to you you could probably reach in and just break them I'm just gonna cut one like that so that capacitor is now separate and I'm gonna do this one like that and just sort of bend them up so there they're definitely not touching and those two capacitors are now free and no longer filtering the signal going to the base of those two transistors alright let's power this on take a quick look at how the video looks now would you look at that that is a remarkable improvement in sharpness now for the color bleed it's really visible right along here you see how this reddish purple color is bleeding into the gray and so is the brown that shouldn't be there and that manifests itself in other places as well like for instance if you have color text over grey background you'll see the color of the words kind of bleed over into the gray a little bit and jumping that inductor and taking that out will remove this effect now if you don't care you could call yourself done cut those two capacitors and you're finished with this mod your thing is now sharp let's jump the inductor and take a look at the improvement alright the problematic inductor is this one right here red red black it's laying flat there's an inductor next to it that's standing on end it's gonna be a little bit harder to see in the video if you just cut this and remove it you'll actually have no color signal whatsoever so if you take it out you do need to jump over it put a little piece of wire there or theoretical you can actually just connect a wire from one side of the other leaving the component in place which basically bypasses it but I'm actually gonna cut it out I prefer it not to be in there at all and to do that I'm going to take my cutters I'm gonna flip them upside down and I'm gonna get in there make sure when you remove this that you leave some of the lead that way you have something you can actually solder the Gipe the bypass wire onto so at this point the leads are there but we have no color like I mentioned so I'm gonna fire up the soldering iron and I'm gonna add a little jumper lead there I'm gonna cut a little piece of wire I'm just gonna hold it down in there and well that's on there and the other side there we go just give it a little poke yep that's a solid connection good it's on there alright let's take a look at how the color bleed looks and there we go the color bleed is for the most part completely gone text is still very sharp it looks good okay we're not totally done remember I mentioned the Zener diode that's right there that little blue diode next to this transistor which is the power generation that needs a little capacitor don't be fooled by this little capacitor here this has nothing to do with the power supply this is used on the video input circuitry which is this stuff over here so I'm gonna add a hundred nano farad capacitor on top of that I first need to tin the Dodge is gonna be hard with the camera in the way and here's a little hundred nano farad says 104 on it this is what I'm gonna tack on there get the old tweezers to hold the part and there we go it's not pretty but it is lower than this I can still put the lid on so the funny thing about this mod is I can see a difference when I had this capacitor in the oscilloscope on the luma a video output on this board it's much cleaner looking but does not really affect the picture quality I honestly can't say I could notice a difference I think an analog video is such a little bit of noise it's just sort of hidden away in the analog nature of it so it really it's up to you if you want to add this but if you have a hundred nano farad cap you might as well just add this on it's easy and it only takes a moment so the final mod is converting this RCA jack to be composite out and all you have to do is cut this wire that runs to the center pin on the RCA jack and then run a wire around the RF modulator over to down here where I'll show you in a second that's where the video connection is input to the motherboard I'm just gonna quickly do this snip right there this little green wire I have is this shielded wire so the center conductor is the white one and then it has this braided part that goes around the outside I'm actually gonna use that correctly so first of all solder the center wire onto this connector right there there's a gap in the shielding right here where you can stick the wire okay I turn this around so it's a little easier for you to see the connectors we're gonna be soldering on right there to this pin this white connector has four pins in it it is the pin right here that is towards the center that's attempting to tin that pin and I melted the connector so that's that's gonna be inevitable it's gonna happen a little bit all right it's kind of ugly but it is on there alright the video cables have been installed the Zener diodes installed I removed and junked the inductor and we cut these two capacitors that is a complete mod done at this point I can even reinstall this cover on here so you'll never even know that a mods been done all right first thing to try is plug in the composite so the s-video cable is not connected I just have the composite through that RCA jack and it's black and white but that's not to worry that is my retro tank is because it's set for our luma chroma so here's a composite video through the retro tank and it looks great not as sharp as the s-video of course but looks rock solid I don't see no interference lines and it's a lot sharper than the composite was originally I didn't really show you the before but cutting that capacitor that filters the composite makes a big difference here as well alright let's unplug the composite and we'll plug in the s-video luma chroma still looking fantastic so sharp so crisp and so nice now I think some people are interested in seeing how this looks on an actual monitor this machine has been modded when I turn this on it looks great unfortunately it's really hard to record a CRT close-up and have it look good and this is because the shadow mask on the CRT is having a little bit of an interference pattern with the sensor inside the camera there's just not quite lining up correctly so things don't look great now one thing to notice though about this monitor is if you look right to the left of the letters there is a bit of what looks like color smearing unfortunately this particular take 4 has that color smearing evident all the time even though when I hook up this same 64 mainboard to the retro TKE you don't see it all so before I remove the inductor on the RF modulator that color smearing is a lot worse so I'm almost thinking that probably inside of this monitor is an inductor on the chroma line as well incidentally I have the sharpness control turned all the way down on the monitor and it still looks this sharp obvious if I turn it up it can be even sharper but now it looks a bit artificially sharpened so yeah this this looks very very sharp on a CRT when you do these mods it's time for a quick test with the alternating pixels to see if we have that rainbow interference pattern if I go to Adrienne's tools there is now a program called test patterns and this is something that I actually wrote myself to allow for alternating pixels between white and black over really any two colors and just like that the screen is full with white and black alternating pixels and it looks fantastic no wavy lines no alternating pixels no interference patterns or the rainbow colors now moving on to the PAL modulator it's very similar to the NTSC one but it has one strange different what I labeled as q4 this transistor here is handling both the luma and the composite video at the same time while the RF has its own dedicated q5 transistor here this is why I said when you cut this resistor as said in that article there's absolutely no effect at all because this whole stage is completely isolated from this a stage up here now back on the NTSC one like I mentioned it might be possible that there's some effects but there really isn't in practice I actually tested that but what's nice about the NTSC version is you can actually connect the composite signal and the luma signal simultaneously say to two different monitors and you will not get a dimmer picture because you're not drawing down the current on these two transistors they're they're separate and isolated but on the PAL modulator if you connect the composite video with 7500 and termination and the luma to another monitor also 75 ohms you're gonna get a dimmer picture when they're both connected and that's simply because as soon as you connect the monitor either one of these that draws down this circuit because the monitor itself has a resistor to ground it's not gonna damage anything it's just gonna look dark until you unplug one of the monitors on the chroma section for the PAL modulator it's pretty much identical to the NTSC one except that inductor is missing it's just not there probably because it's not needed for the way powell color works and also c8 this capacitor is to the right of this c10 capacitor on the ntsc one otherwise these stages are essentially identical and they both feed up to the RF and the composite signals using the same capacitor connections just like on the NTSC and then very interesting is the power stage here looks identical except there is a capacitor in parallel to the Zener diode it's a larger electrolytic so it's not ideal why did Commodore leave this off for the NTSC one I couldn't say here's my pal c64 main board this was donated by Dave in the UK back in January of 2020 I just noticed this has the 65-69 r1 Vic 2 chip these are the early ones that only have the limited luma I really only thought these came on the super early c64 s and that this board would have had the later revisions that didn't have that same limitation anyhow let's get the cover off this RF modulator it looks like it has a little tab here that's soldered down that is different than on the NTSC ones there we go so this is the video output from my pal 250 407 board and just like the NTSC ones very soft along these letters here I'm also seeing artifacts in solid colors notice the solid blue has alternating lines of blue and darker blue there's a phenomenon called Hanover bars if you check out the Wikipedia article on the subject appears to be something to do with phase errors into color information let's first correct this blurry video and then we'll take another look at the Hanover bars okay so this modulator is an MD 6ue 3603 and I have the schematics right here for it so if you recall there was only one issue with this one and it's the capacitor c9 that we have to cut going to the base of this NPN transistor the capacitor to cut is this green one here that's right between this transistor in this larger capacitor it's this small green one I'm trying to move it back and forth but I can't I'm trying to get in here to cut it with the camera in the way but unfortunately I just can't get a good view of it so I'm gonna need to move the camera out of the way while I cut this well it was a pretty tight fit and I had to cut through the capacitor and then cut the leg off that was the only way I could do it so if I need to restore this back to it was I'll just have to desolder the entire arm modulator and put a new capacitor on so let my experimentation help you out if you have one of these RF modulators well let's power this thing up and see how it looks on the monitor all right there we go well I'd say that there is an improvement but I must say it's not as dramatic as it was on the NTSC machines I'll do an a/b comparison in editing but it's definitely sharper but it's not as good as the NTSC s turned out okay I have a test pattern up on the 64 and it has various band widths here including four megahertz this is basically alternating white and black pixels as close together as possible and I hooked up the oscilloscope to the luma output of the RF modulator but also the luma output right from the Vig - and I figured out why the picture is so soft here's a single shot of the luma signal coming from the Vic - chip you can see why it's so soft the rise time and the fall time is very slow therefore there isn't a lot of time spent at the top so theoretically it should go up then it should go through the duration of the pixel and then drop down to black and should be alternating and that would explain why it's so soft and this is coming directly from the Vic - chip and not from the RF modulator when I check after the buffers in the RF modulator it basically looks very similar to this so if this is not good and clean then the output of our modulator is also not going to be that great so unfortunately there's no way to fix this particular problem I'm running the same test on an NTSC Vic - chip results in a much more squared waveform which means there's more inherent sharpness in the signal it turns out the issue is either with my particular Vic - chip or all of these are ones I found another Powell Vic - chip and I stuck it in this machine and as you can see from this picture it is far far sharper and looks as good as the NTSC ones other than some minor color fringing of course those hannover bars which are still visible it looks great as far as the mod to output composite through the RCA jack it's actually no different than on the other one you just run a cable from this pin right here all the way to here you just cut this RF connection and you can reuse this RCA jack for composite and finally we have the NTSC modulator that's used on the later revisions of long ports this is the actual common or schematic that I was able to take like I said before it has the inductor here on the chroma signal which means it's for NTSC color I don't have the schematics or even a modulator to reverse for the palettes so I couldn't tell you what needs to be done there but I have a feeling based on the rest of this there's probably nothing that needs to be done on the PAL modulator or whatsoever the design of the luma input section here is a little bit more like the PAL modulator on the earlier one there's only a single transistor here that handles both luminance and composite so the same problem applies that if you plug a monitor into both of these simultaneously it will create a darker signal but if you notice here on the base of q2 transistor what's missing on this there is no capacitor down to ground which means there is no low-pass filtering happening on this modulator this right here explains exactly why this modulator has a sharp video output while the other modulator has a blurry output the chroma stage is basically exactly the same as on the earlier modulator and just like the NTSC one it has the same 22 micro Henry inductor here and I wrote remove and cut or remove and jump l1 and this will have the same effect of removing the color smearing which this modulator absolutely has I always really liked this version of the comer 64 our motherboard because the output looks so sharp as explained down here there's no filter going on but I didn't like the color smearing and the delay that was on the color line which is coming from this l1 inductor so I'm glad to have figured out that it's a simple thing just to jump over that on this and it completely eliminates that color smearing so for modifying the 3405 modulator there's not much to it this is the inductor that you're gonna be taking out red red black all we need to do is cut this and jump it and now it's jumped I just installed a short piece of wire there I did test by actually installing a piece of wire over the inductor in place and that seems to work equally as well so you can honestly do either one of those I also went ahead and used a bodge wire to go from the composite pin that goes to the motherboard there to the RCA jack and that gives me RCA out on this modulator all right back to the henna or bars discussion so you can see them there in the purple in the red they're basically showing up in all the colors I don't really see it in the yellow now initially when I first got a pal 64 and started playing with things in PAL signal and I saw these bars that were rather ugly I didn't really know what was going on so I started doing the research and it doesn't seem to be a lot of information out there other than the fact that very old monitors and TV sets exhibit this problem but also some very high-end professional monitors have problem as well and my retro tank 2x which is what I'm connected to right now clearly exhibits this issue in my reading the way around this particular problem and the reason why most people in PAL regions probably never even seen these bars is that most TVs and displays have what's called a delay line inside and what it does is it averages the color information between two lines so that any differential color from the hen over bars will be wiped out because of that averaging but of course there's an undesirable side effect and what happens is it halves the number of lines of chroma you have and while that makes solid colors appear perfectly solid and not with these lines any longer it will reduce the resolution and I have a particular test to demonstrate that exact problem here's a very cool program for the 64 called playing with colors and what it's doing is its generating some additional new colors by alternating on every other line from the 16 colors that are available on the 64 well down on the bottom row are the solid colors on the 64 itself and sure enough I see these Hanover bars but if we take this square for example it looks like it's made up of dark grey which is this square and this lighter blue and you end up with this sort of shade but of course we're clearly seeing these different lines that make up this color because the retro tank is not averaging this color information but I have this box which is a scart two HDMI converter I got from China and I know it will eliminate the Hanover bars by averaging the color information but of course at the cost of the vertical chroma resolution let's test this out and there we have it there are no Hanover bars these boxes down here are perfectly solid we have no alternating lines but look up here remember this box we were talking about it's made up of dark grey and this light blue color mixed together but it looks like a solid dark blue in fact all of these squares here look completely solid and that's again because of the averaging of the chroma information that resolution is lost that definition is gone so yes definitely NTSC has trade-offs but as you see by this Pal has some trade-offs as well I tried to show playing with colors too on an NTSC machine and this is what you get does not work well that's gonna be it for this video I know I covered a ton of content but hopefully you're able to follow and find it useful if you modify your converse 64 RF modulator I'd love to hear about it in the comment section below let me know how it works out for you and then of course if you liked this video I'd appreciate a thumbs up if you didn't you hit that thumbs down button subscribe for more videos that we lots more in the future put any other comments and suggestions down in the comment section below and thank you very much for watching stay healthy stay safe and we'll see you next time [Music] [Applause] [Music]

Channel: Adrian's Digital Basement

Views: 71,243

Keywords: Longboard, 250407, KU-14194HB, C64, Commodore 64, breadbin, rf modulator, 250466, 250441, 250425, 250469, MDA-VA3405, MD6-VA3403, MD6-UE3603, retro computer, vintage computer, commodore computers, 8-bit

Id: vTn36UaUfrk

Length: 38min 51sec (2331 seconds)

Published: Sat Apr 11 2020