Build S-Video and Composite Video mods for TRS-80 Color Computer 2 ! || A late

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  • เผยแพร่เมื่อ 23 พ.ย. 2024

ความคิดเห็น • 56

  • @chasbader
    @chasbader 2 หลายเดือนก่อน

    That was a great video... Makes me feel like I'm not alone poring over those 1374/4 schematics.... Thank you

  • @Flatwoodsdad
    @Flatwoodsdad 4 ปีที่แล้ว +3

    Thanks for taking the time to do this. This has got to be the most in depth study and explanation of the coco2 video-out circuit on YT. But man it's a lot to take in. It's good you have it time bookmarked cause I'm gonna have to come back and watch the mod that pertains to mine again. Again thanks a lot. Who knew there was so much going on inside that little metal box.

  • @natethefighter
    @natethefighter 4 ปีที่แล้ว +3

    This is an EXCELLENT reference video. Thank you so much for taking the time to do this!!

    • @acs8-bitzone651
      @acs8-bitzone651  4 ปีที่แล้ว +1

      YW, I'm glad you appreciated the effort! Thanks for watching.

  • @alexabadi7458
    @alexabadi7458 2 ปีที่แล้ว +1

    To me CocoVGA is the way to go, easy to install, great colors and high resolution on a TV/monitor with RGB input.

    • @acs8-bitzone651
      @acs8-bitzone651  2 ปีที่แล้ว

      Yes, it's definitely a nice product. Thanks for the views and comments!

  • @boost_prod7600
    @boost_prod7600 2 ปีที่แล้ว +1

    Congratulations on 850 Subs 🎉🎉🥳🥳🎊

  • @estebanvillalobos2303
    @estebanvillalobos2303 2 ปีที่แล้ว

    i modded my early model coco2 with your instructions and it worked great first try, fun way to kill an afternoon and no more rf for me!

    • @acs8-bitzone651
      @acs8-bitzone651  ปีที่แล้ว

      Great! I am releasing two episodes this month with updates on composite mods.

  • @JimSky
    @JimSky 4 ปีที่แล้ว +1

    I just received my first Coco2 in the mail today. First thing I thought was video mod. Your video was the third I watched and I wish it had been the first. So thorough and well explained. I have managed to not learn anything much about various video modes until your video. Anyway, very well done. Also, your hair is awesome enough to have it's own channel.

    • @acs8-bitzone651
      @acs8-bitzone651  3 ปีที่แล้ว

      Thanks Jim for the amazing comments and feedback! I am planning on revisiting the composite video during winter holidays. I believe there is room for a cleaner image. Also, make sure to see the video released just a couple days ago by Retro Hack Shack. He shows off a Pi-Zero based sandwich of 3 boards made by some talented designers that is an HDMI output solution for our Cocos. I was thinking about using an external Video-to-HDMI converter from Amazon, $20 range, to do that. I am curious how the video quality will look.

    • @JimSky
      @JimSky 3 ปีที่แล้ว

      @@acs8-bitzone651 I purchased a composite to VGA converter box as I don't have a composite monitor. The converter also accepts S-video. I bought this initially to use with a modified TS-1000 but I have yet to get that working properly. The levels coming from the TS-1000 are not right. But now the Coco is here and there is an even better use for the converter.
      BTW my plan to fix the TS1000 output is to build a variable gain video amp with variable offsets to allow experimenting with waveform.

  • @RetroTechRepair
    @RetroTechRepair ปีที่แล้ว

    What an Awesome Video AC! Thanks so much for this. I have recently performed this mod and am uploading a video of my experiences with it as we speak. I will include a link to your great work. I hope the it will send some much deserved traffic your way! Thanks so much for this. Roger

    • @acs8-bitzone651
      @acs8-bitzone651  ปีที่แล้ว +1

      Late comment here, but I watched it back at the time and it was great. thanks for the shout out!

    • @RetroTechRepair
      @RetroTechRepair ปีที่แล้ว

      @acs8-bitzone651 Great AC thanks so much. My coco2 is still going strong thanks to your amazing work

  • @MrMikeHawkey
    @MrMikeHawkey 3 ปีที่แล้ว +1

    I'm interested in CoCo 1 composite out but I found your video so informative, it has helped me understand the CoCo 1 video output also. Thanks

    • @CoCoNutBob
      @CoCoNutBob 2 ปีที่แล้ว

      Mike, did you ever get your CoCo 1 modified with composite output?

  • @lazarian4428
    @lazarian4428 2 ปีที่แล้ว

    Thank you for making this video. I wish I would have found it sooner. I have a couple CoCo 2's that I've been trying to get a proper composite signal out of. Your in-depth explanation of the various methods really help a lot!

    • @acs8-bitzone651
      @acs8-bitzone651  ปีที่แล้ว

      Check out my new episode on the simplest composite mod. I will be releasing a second related episode in a couple days.

  • @cocoe68
    @cocoe68 3 ปีที่แล้ว +1

    First of all, many Thanks for your time around this hobby for so many people like me.
    About septandy, it has been very helpful because tandy color computers have to many possible broken parts and it's time to upgrade like my Coco2 video output to actual lcd displays, thanks.
    This episode, from my point of view (not an expert) is a little bit complex to follow, i would prefer to get the explanation about issue and your solution and then a clear procedure as a resume including diagrams you included in Google Drive shared folder, thanks. I would add some pictures with your final board modified, both faces.
    A printed circuit board as a kit might also be interesting.
    Continue sharing your knowledge because it is really nice for me!!!!
    My nickname is Cocoe since near 20 years ago from Extended Color Computer in MAME.

    • @acs8-bitzone651
      @acs8-bitzone651  3 ปีที่แล้ว +1

      You are welcome. Thanks so much for the feedback. It is quite helpful. As a matter of fact, I am thinking about doing another round with composite video to make improvements on the picture quality. Hang in there, and maybe we will get a pcb designed that has the optimal composite and s-video in one.

  • @TheRetroChannel
    @TheRetroChannel 4 ปีที่แล้ว +2

    Nice work AC! I built your S-Video circuit yesterday but unfortunately it still requires adjustment of the chroma output to play nice with different displays when switching to pmode4. Same issue that I had with my circuit. But apart from that I found the output to be similar quality.
    I think the chroma issue is limited to PAL machines, and seeing as you clearly have a bit more knowledge on circuit design than I do, I would definitely prefer to use your design in the future, if I ever get another CoCo that is. Anyway, thanks for sharing

    • @acs8-bitzone651
      @acs8-bitzone651  4 ปีที่แล้ว +2

      Hello TheRetroChannel ! I saw your CoCo 1 video while I was working on the S-Video mod! It was fortuitous and I learned plenty from yours, believe me. That is the cool thing about having all these interesting channels like yours to view; there is something to learn everyday. About the variable resistor you are needing to add in series with the Chroma output. I'm not familiar enough with every S-Video variation that monitors and devices have implemented so I don't know the cause of this issue yet. But I noticed that in the bhabbott.net.nz reference that I showed in my video, that he had an AC-coupling capacitor in series with his 75-Ohm Chroma output. I didn't know why it was there, and I haven't seen it in other implementations. My guess is that some monitor inputs do not tolerate as much common mode voltage offset, or DC offset, and want the signal closer to ground. Did you discover that your FrameMeister needed 1k by experimentation or did its documentation cover it? The 1k would attenuate the voltage level, but I wonder if the AC coupling cap would also have worked. It wouldn't attenuate, but it would shift the common mode voltage closer to the monitor input.

    • @TheRetroChannel
      @TheRetroChannel 4 ปีที่แล้ว +1

      @@acs8-bitzone651 Thanks AC. I'm pretty sure I did try to AC couple the chroma but to be honest I tried so many different things and it's possible I only AC coupled the luma. Like I said in my video, circuit design is not my forté so I basically threw everything I knew at it and ended up with a partially working design 😄
      I didn't know about the bhabbott one until after I made mine, I think MindFlareRetro tipped me off to that one. So it may be worth a try, as I assume that one is also based off using a PAL machine. As for the resistor value, again that was just trial and error. There were 4 displays I tested mine with, the framemeister needed 1k, an early LCD monitor needed around 300ohms, my USB capture device was happy with 22, and my crt didn't really care what the value was.
      Anyway, I really appreciate you sharing your design and thoughts. I will revisit mine in the future and try AC coupling the chroma. Hopefully we end up with a design that works for everyone, it would be nice to have a proper pcb made that anyone can easily build themselves. Cheers

    • @acs8-bitzone651
      @acs8-bitzone651  4 ปีที่แล้ว +2

      @@TheRetroChannelAgreed, one that works for all, and then we design a PCB. Let's do it.

    • @TheRetroChannel
      @TheRetroChannel 4 ปีที่แล้ว +1

      @@acs8-bitzone651 Right, I'll play around with it in the next few days and hopefully find a solution that works. Then it's just a case of designing something that fits the CoCo. I think there will have to be a couple of different PCB designs due to the different cases and modulator placements of the Coco's but we'll figure that out later

    • @acs8-bitzone651
      @acs8-bitzone651  4 ปีที่แล้ว +2

      @@TheRetroChannel Right on, I believe you are referring to the CoCo 2 vertical and horizontal versions of RF modulator, yes I will upgrade both styles with the eventual PCBs. Looking forward to this!

  • @atarimex2643
    @atarimex2643 2 ปีที่แล้ว +1

    Great presentation. I followed the new S-V mod from The Retrochannel on my Coco1 NTSC ….S-Video works great, Monochrome works excellent from Luma output no chroma.…..but composite didn’t work. I tried without the diode, with the diode and played with different cap value, no luck. Could you post the composite on. cable mod? I would like to try it. Thanks a lot!

  • @ibmmac
    @ibmmac 3 ปีที่แล้ว +1

    Excellent Job with the video! I just got an early model Coco 2 64k given to me with an unknown history. I only have LCD TV's and CRT composite monitors, so I am unsure how to test before I build the video mod. I am missing the RCA to TV converter. I have used a jumper cable to connect the center of the RCA jack to the Coax on the LCD TV getting lines and too fuzzy image to tell if it booted or not also tried clipping to my B&W 4 inch TV and just got fuzz. I would imagine I need a load like 75ohm for correct operation, however I am not sure what to expect. My end goal is to get it working with an S-Video mod.

    • @acs8-bitzone651
      @acs8-bitzone651  3 ปีที่แล้ว

      The original TV/game switch boxes are not really needed now. Some may have been 300 ohm to 75 ohm converters but that was for the flat ribbon style conductors from the antenna. Today people are using a cable from the CoCo to an RCA to RF adapter at the TV. They can be found on Amazon, and this provides a cleaner connection. Good luck with your s-video upgrade!

  • @kokodin5895
    @kokodin5895 4 ปีที่แล้ว +2

    fun fact
    i live in poalnd and i fell in love n one domesticly made tv , but only after 20 years of not having one i was able to buy one for myself and only then i discovered it only had rf input
    so while recaping i added svideo and rgb input based on factory schematics
    the thing is tz could only be hacked to accept full composite signal or YCbCr, (y r-y b-y) so my tv could use your coco computer without modulator box at all
    and the other fun part of it that conversion of rgb to YCbCr, was mady by few transistor and resistor networks with no ic's so there is a chance coco chip could be replaced entirely by some similar circuit

    • @acs8-bitzone651
      @acs8-bitzone651  4 ปีที่แล้ว +1

      That is completely awesome. You practically made the computer and TV one integrated unit! I appreciate your information because in the back of my mind I'm always thinking "how much longer is this IC going to work, and how many more of them are even out there for purchase". We will probably come back around to this eventually as we begin to deal with the aging system and keeping the vintage alive and well!

    • @kokodin5895
      @kokodin5895 4 ปีที่แล้ว +1

      @@acs8-bitzone651 well using factory schematic to build an av inpiy module (designed for zs spectrum) from components oryginal module was made is not a big deal, especially when i had factory service manual with pcb layouts and schematics (i made the board a mirror image though), making an integrated circuit from an internal schematic isn't a big deal eaither, i even have somewhere around homemade 555 ic on a breadboard
      in your case, you scrolled trough the modulator ic datasheet and there was that internal structure schematic, you could probably made that from transistors and even remove area of the ic that were not used by composite and s video generation, making it really simple transistor based circuit anyone could make (well easy is relative)

  • @davidkroeker1821
    @davidkroeker1821 4 ปีที่แล้ว +1

    Very cool, thanks for sharing all the technical details and the circuit options you found and considered. It makes for a long video, but was very informative! This is a video I may need to watch a couple of times to really understand all the details. Having the Composite output for PMODE4 artifact colours and S-Video for all the other modes reminds me of how I use my CoCo3 with Magnavox 8CM515 monitor that has composite and RGB video inputs that I can switch between depending if I want to see artifact colours or not. I wonder if I could use a Commodore 1702 monitor that has selectable composite and luma/chroma video inputs to serve a similar purpose with a CoCo2 that has been modified to provide composite and S-Video out. Also, I wonder if it is possible to use the CoCo3 RGB patched versions of artifact colour programs to see colour on your S-Video signal on your newer CoCo2? Those versions have been patched to use PMODE3 graphics instead of PMODE4 with artifacts. If it is possible, that would make your S-Video mod even more useful for CoCo2 users! Patched versions of many games are available at colorcomputerarchive.com (search for RGB Patch).

    • @acs8-bitzone651
      @acs8-bitzone651  4 ปีที่แล้ว +2

      Thanks! If I had the CM1702, I would just try it and let you know. However, one would think the S-Video would connect perfectly. On the Commodore 64 S-Video, I read that certain monitors need a series resistor in one of the S-Video lines. Hopefully, a minor tweak like that would be the most that is needed in case there is a compatibility issue. For the composite circuit, R101/R102 began as potentiometers and then I dialed in the offset and gain into the middle of the range and changed the pots to discrete resistors. Hopefully something like that would be the most you'd need to do. Regarding the RGB patch, I was wondering the exact same thing. Before you informed me that it was a PMODE3 conversion I was hoping it was not some special mode only available in the CoCo3. That provides some hope those would work in the Coco2. Wonder if anyone has tried. I'd like to try that myself. I first need a way to transfer DSK images. That should be my next initiative.

    • @davidkroeker1821
      @davidkroeker1821 4 ปีที่แล้ว +1

      ACs 8-Bit Zone I highly recommend getting the CoCoSDC! It is indispensable and the perfect solution for getting DSK images from downloads onto your CoCo. DriveWire is another good option. If I had a CoCo2, I’d like to try the RGB patch versions of some games over SVideo. I don’t see why it wouldn’t work, but not certain.

  • @MartianTech
    @MartianTech 2 ปีที่แล้ว +1

    33:10 - The photos show both a 7805 and a 7812 voltage regulator (*possibly supplied from a voltage doubler) on the zippster's card, so he may not only be using a higher voltage but also using a separate +5V supply that is isolated from the main supply. And it looks like 470 uF filter caps. Apparently having a clean power supply is critical in producing a high quality video signal. You kind of mentioned this at 44:57 and 57:44, but didn't show the difference which might have been instructive...

    • @acs8-bitzone651
      @acs8-bitzone651  2 ปีที่แล้ว

      Yes, the larger capacitor value did clean the power supply and improve the video quality. I eventually found the schematics of the Tandy educational coco with direct output composite video, the basis for the card you mentioned, but not in time to make it into this video. Thanks for the note!

  • @williamscott1094
    @williamscott1094 3 ปีที่แล้ว +1

    Great video AC. Are the files still up on your Drive account? I don't see them..

    • @acs8-bitzone651
      @acs8-bitzone651  3 ปีที่แล้ว

      Hey thanks. When I click on the link at the very bottom of the video description, it takes me to the google drive. Then navigate into the trs-80 and then svideo_composite folder. The schematics are there. Let me know how it works for you if you could.

    • @williamscott1094
      @williamscott1094 3 ปีที่แล้ว

      @@acs8-bitzone651 Thanks AC, got it. I needed to enable third-party cookies. Apparently Drive requires that. Thanks again. Your video has answered many questions I had on the 1372 composite video setup.

  • @franciscomeza8905
    @franciscomeza8905 11 หลายเดือนก่อน

    Exactly what type if diode did you use on the 1372 I.C. between pin 13 and pin 14?

  • @SP-nt4sr
    @SP-nt4sr 4 ปีที่แล้ว +1

    What are the requirements on the transistors. Are there any alternate NPN/PNP pairs that could be used?

    • @acs8-bitzone651
      @acs8-bitzone651  4 ปีที่แล้ว

      I started out using those that were specified in the MC6847 datasheet, however, others such as TheRetroChannel have have good results with whatever npn/pnp pairs they had handy. The general signal level transistors all have good enough qualities for this. The current and power requirements are low, the BW is not unusually high, the gain doesn't need to be extraordinary, etc. Seems most will do. Thanks for the question, and let us know if you get some results with other transistors!

  • @chrisdurys2210
    @chrisdurys2210 4 ปีที่แล้ว +1

    AC do you have way to leave a link to your schematics and photos. My old brain needs a piece of paper to build from, thx

    • @acs8-bitzone651
      @acs8-bitzone651  4 ปีที่แล้ว

      I'm working on a way to post them. I don't exactly have a go-to hosting site that I like, but I'll try to choose something. There's Imgur and Google Photos. Maybe one of those would be convenient?

    • @acs8-bitzone651
      @acs8-bitzone651  4 ปีที่แล้ว

      Hey Chris, I added a link to the schematics below the video the description. If you attempt to retrieve files from there, would you mind letting me know whether it works for you? Thanks, AC

  • @TheBilusic
    @TheBilusic 4 หลายเดือนก่อน

    the circuit described at 44:16 is inverted video. Found out when I finished building it.

    • @TheBilusic
      @TheBilusic 4 หลายเดือนก่อน

      weird things..... I somehow forgot to connect the supply line capacitors to the ground which gave me an inverted video. Curiouser and curiouser...

  • @GMan958
    @GMan958 4 ปีที่แล้ว +2

    Hi there...there is a recurring problem in the CoCo community that many people would like to have a solution for. I have two CoCo2 with this problem. How can I get in touch with you, may be you can make a video about it

    • @acs8-bitzone651
      @acs8-bitzone651  4 ปีที่แล้ว +2

      Thanks for subscribing by the way! To your question, I'd like to learn more about this issue. So I've added my information on the "AC's 8-Bit Zone" channel, on the "About" screen. I figured that would totally throw off the spammers and they would be completely unaware.

    • @GMan958
      @GMan958 4 ปีที่แล้ว +1

      @@acs8-bitzone651 Done...check your mail

  • @tenminutetokyo2643
    @tenminutetokyo2643 ปีที่แล้ว

    Replace the 2 DC regulators. It shrinks everything down, run much cooler and you can dump the heat sinks.