Add HDMI To Your Vintage Computers! Part 3 --OR-- TRS-80 Coco 1 Repair and Mod Part 2

[@borayurt66]

Came across your channel while searching a good build video for RGB2HDMI project. Lots of famous retro computer channels made a video on this great project, but none of them did an in depth review like you did. I watched all 3 videos, and got a lot of useful info for my future build. Also subscribed and will be following your new videos too. Thank you!

[@RetroHackShack]

Thank you Bora for those kind words!

[@brostenen]

I have the special adaptor for Amiga500 OCS. Really happy with this solution.

[@RetroHackShack]

Really glad to hear that! I haven't tried on my Amiga yet.

[@brostenen]

@@RetroHackShack The adaptor I have is an internal one, that sits between the board and Denise chip.

[@JimLeonard]

Very comprehensive, very informative, and I appreciate the 4K workflow. I'll be trying something similar to this for my CGA systems. Keep up the good work!

[@RetroHackShack]

That's good to know. I wasn't sure if it was worth it or not to do 4K.

[@TheRetroChannel]

Wow, amazing work. I was thinking of trying to pull the YUV from the CoCo but this is a huge step up from that. Thanks for sharing Aaron.

[@RetroHackShack]

Just FYI - There will probably be a part 4 because I have been working with one of the developers and we now have artifact colors working with the HDMI output as well as support for the Coco 3's RGB port. I think there was a trade off you had to make with your solution with the artifact colors IIRC.

[@TheRetroChannel]

@@RetroHackShack Cool. I did lose artifact colours, but as mine is a PAL system they don't form solid colours like NTSC. So I'm not sure the same could be done for a PAL system, I guess it depends how the board(s) translates PAL signals

[@RetroHackShack]

Yeah. That just it. This can add the artifacts for PAL systems. From the forum ... "The artifact code works on the Dragon and PAL CoCos and also the PAL Apple II variants."

[@TheRetroChannel]

@@RetroHackShack Oh that's awesome. I will definitely have to build one to test it out

[@drone_video9849]

@@RetroHackShack Did you ever get the Coco 3 version tested?

[@whitehedr]

I was able to get the RGBtoHDMI working with a Dolch LAM4850 logic analyzer. I am using the Tandy profile. It is not 100% Pixel Perfect like Adrian says about his conversions but it is darn close. I have a lot to learn about the device. The Dolch puts out a 3 signal video in 6:30 TTL levels. HSYNC, VSYNC, and VIDEO. I had to invert the video signal with hardware to get the picture I needed.

[@RetroHackShack]

Nice job!

[@CoCoNutBob]

I finally connected up my CoCo 1 to the RGBtoHDMI. After multiple cabling errors I finally got it working! Woohoo!!!

[@RetroHackShack]

Awesome! How's the picture quality?

[@CoCoNutBob]

@@RetroHackShack Superb! I was initially struggling with the screen going blank whenever the menu turned off, but that seems to have stopped when I set a specific output resolution instead of "auto". Will do a comparison video soon.

[@CoCoNutBob]

@@RetroHackShack youtu. be/_65X4UgN1gQ

[@di4352]

Analog to digital sandwich, my favorite.

[@daga68]

Very good HDMI Output, please made a Game Play of Zaxxon !!

[@amberisvibin]

the way this works is very interesting, I would have used a standard ADC but this is much more precise

[@PJBonoVox]

Great video series man, enjoyed the detail. Was hoping you might show the scanline emulation stuff for shits and giggles though. Maybe next time 🙂

[@RetroHackShack]

Sure. I think there will be a part 4 now that this is working with the Coco 3 :)

[@rockyhill3]

I finally finished assembling both the analog board and rgb2hdmi and wired it to my CoCo 2. It works,it's usable, and it's cleaner than RF but it has annoying sparklies. I've adjusted the settings as best as I can understand with marginal improvement so I'm thinking I broke something or there is a bug in the firmware. I'm going to go over what I did to make sure it isn't something on my end and if it's good on my end I'm going to submit an issue on the repo. However, before I submit the issue, I want to know if you saw sparklies when testing it out on your CoCo 1. If you did, were you able to fix them and how? Thanks for the video and for your feedback it really helped me get this amazing board together. Thanks!

[@RetroHackShack]

I am assuming this is an NTSC coco and not PAL? All I had to do was "auto calibration" to get the best phase and that fixed some minor glitches.

[@rockyhill3]

@@RetroHackShack Yes it's NTSC, unfortunately that didn't solve it for my setup and I tried with two different CoCo 2's. I'm going to have to make a second analog board to compare. Thanks for replying!

[@rockyhill3]

I was looking through the repo but I can't seem to find how to wire the board to the VDG. Did you get that from somewhere else? Fantastic video!

[@RetroHackShack]

Did you look on the wiki? See if this helps github.com/hoglet67/RGBtoHDMI/wiki/Cables

[@rockyhill3]

@@RetroHackShack I did but it was 4:00am so naturally I missed it.... Thanks!

[@johnsnook2358]

Woo Hoo! repeat to infinity!

[@RogelioPerea]

Great project!

[@daga68]

I really wanted to see you sorldering the wires at 31:00, sniff sniff

[@CurtisBoyle]

Awesome video - glad it turned out so well. We should get you to join in on the CocoTalk weekly game challenges. I do have one question - from seeing Daggorath, I presume that you don't get artifacting colors on the HDMI out?

[@RetroHackShack]

Correct. No artifacts, but I think they might be able to be emulated. I still have this hooked up. Let me check.

[@RetroHackShack]

It does have artifact emulation, but I can't get it to do anything on D of D. I will ask in the forum.

[@CurtisBoyle]

@@RetroHackShack - D of D Doesn’t use artifacts (not on purpose, anyways), so you would need a different game to test. Do you have any others handy?

[@RetroHackShack]

@@CurtisBoyle I could swear mine had artifacts as a kid. What do you recommend? I can always plug in my Coco SDC and load something up.

[@paulshoemaker4761]

​@@RetroHackShack Great video! D of D will definitely show the artifacting (as any program using the 256x192 PMODE 4 graphics screen will when using native output). I think what Curtis means is Daggorath doesn't purposefully make use of artifacts to show objects in different colors. An adventure game like Sands of Egypt is one example (of many) where artifacting is deliberately used.

[@johnglielmi6428]

I most likely would just solder to the bottom of the board myself, seams a better choice for me

[@RetroHackShack]

Agreed. I was just being lazy.

[@johnglielmi6428]

@@RetroHackShack Yeah I only said that because I wouldn't want anyone, watching this very informative video, to accidently solder the chip into the socket is all

[@dans.8198]

Great video! Is the pinout the same with the version 4 analog board? (M62364G DAC Issue 4A-T-GS8743).

[@RetroHackShack]

Yes

[@VictorTrucco]

how about the games that use color artifacts? Black and white on HDMI?

[@RetroHackShack]

It works! See the next video in the series for a demo.

[@thatguyontheright1]

Wait a CoCo 1 and 2 can output YUV natively? Why can't I find anything about this on the interwebs? Wana send me the pinout or is that a secret?

[@RetroHackShack]

It's in the technical reference manual. Also, you can find the pinout for the cable on the GitHub Wiki. That should get you there.

[@thatguyontheright1]

@@RetroHackShack Interesting. I'll have to try this with a TV that has component inputs sometime. Cheap RGB and don't have to shell out money for the VGA board.

[@star2gmail]

You didn't test a game that uses the red/blue/white/black color set which relies on composite artifact colors. I would be interested to see if that works.

[@star2gmail]

Try playing Pegasus and the Phantom riders. Let's see if it comes out in color or black and white.

[@RetroHackShack]

It didn't then, but it does now. You can see an example on part 4.