RGB/YPbPr Intellivision Thoughts

[+-^CrossBow^-]

The issue with Diner was occuring with my SVA not the Intelly 2 with the bad STIC. And again if you were reading what I typed, I actually had fewer video dropouts with the bad STIC IC installed vs a working one. 

 

Anyway, here is how I was able to replicate the Diner issue. I started on level 2 as I recall and it was about the 2nd or 3 screen in the colors of the screen had a lot of blue as I recall and maybe green? Anyway, it was causing the RGB output to drop out on through my Tink2x SCART every few seconds in that testing.

 

It was definitely related to certain amounts of combination of colors on the screen that would trigger the dropouts. Also to make sure it wasn't a power issue on my Tink2x I tested using the USB ports on the TV to power the Tink2x and also a separate ipad charger to make sure. The issue happens regardless.

 

[the_crayon_king]

4 hours ago, -^CrossBow^- said:

The issue with Diner was occuring with my SVA not the Intelly 2 with the bad STIC. And again if you were reading what I typed, I actually had fewer video dropouts with the bad STIC IC installed vs a working one. 

 

Anyway, here is how I was able to replicate the Diner issue. I started on level 2 as I recall and it was about the 2nd or 3 screen in the colors of the screen had a lot of blue as I recall and maybe green? Anyway, it was causing the RGB output to drop out on through my Tink2x SCART every few seconds in that testing.

 

It was definitely related to certain amounts of combination of colors on the screen that would trigger the dropouts. Also to make sure it wasn't a power issue on my Tink2x I tested using the USB ports on the TV to power the Tink2x and also a separate ipad charger to make sure. The issue happens regardless.

 

I remember talking about what STIC was doing what in regards to Thunder Castle. I must have missed the part about Diner. My bad. This is a pet project and I don't have as much free time as I would like to dedicate towards this.

 

Anyway, I have been going up to level 5 (sometimes 6) with no sort of video dropout.

That is on two different model 2s. I will try my other model 2 and my model 1 to see if I can determine anything.

[+-^CrossBow^-]

I will see if I can replicate the issue through RGB on my Intelly2 and record it on video. Again the three games I was playing that had the most issues for me was:

 

-Thunder Castle

-Diner

-Maria

 

I did try a few other normal released games like Burgertime, Night Stalker and don't recall any drop outs on those games. But I will test it both with my actual carts and through the LTO very soon when I can.

 

[+-^CrossBow^-]

Current versions of the board that were sold on ebay do work on the tink2x Pro through component for the most part. I did notice some video dropout on component on the title screen to the third level maze on Thunder Castle that shows the demon dude on the left side. That screen was dropping out quite a bit, but the actual game play screen seemed to be stable.

 

Will do more testing through component since that seems to be working better on my testing so far vs the RGB output.

 

[the_crayon_king]

14 hours ago, -^CrossBow^- said:

Current versions of the board that were sold on ebay do work on the tink2x Pro through component for the most part. I did notice some video dropout on component on the title screen to the third level maze on Thunder Castle that shows the demon dude on the left side. That screen was dropping out quite a bit, but the actual game play screen seemed to be stable.

 

Will do more testing through component since that seems to be working better on my testing so far vs the RGB output.

 

I'm still convinced something in the setup is different than mine. Since our scalers and kits are identical that only leaves the TV or the console.

 

Anyone have similar issues to report? Might be something I can fix going forward.

 

---------------------

Just a heads up but I have the code for the new board compiled and it fits RGB/YPbPr and two full color palettes. I have mthompson's and imbezerk's (default) as the two different ones. I could switch either one of these if there is something preferential out there.

 

Because sync is now done with a different method entirely it should work on the OSSC. However, because the method is completely different than the old method it will really need to be put through it's paces as far as compatibility with any one game. I also want to test PAL compatibility at some point.

[+-^CrossBow^-]

Well so all the testing I'm doing lately is on my Intellivision 2 since it is easier to get into and test with etc. I have a different RGB setup in place on my SVA now and that will be getting another new RGB board installed this weekend for additional testing there. I do have another Intelly 2 on the way that is in working condition, and will likely install my second of your two boards I have here into it and see if anything different comes from it. BTW @the_crayon_king I send you a PM with some vid showing my current results on YUV output.

[the_crayon_king]

I will be looking into audio specifically on the model 2.

Currently the audio line looks like this with no audio applied.

This is a 120hz hum. I think the only way to fix it is to lift the audio pins and amplify the signals on a different board. Right now it is being amplified right under the power board which is probably the worst place for it. Unless RF audio is supposed to have a 120hz carrier this looks pretty bad.

A capacitor will not fix this but maybe some filtration could. Still I believe it will be easier to fix by lifting the pins. This is something that can be fixed with it's own independent board. For various reasons I am not going to include audio on the RGB kit.

Edited April 16, 2021 by the_crayon_king

[+-^CrossBow^-]

I actually have the audio on my intelly 2 coming straight from the point where it was going into the RF modulator. I then have a 10µf cap attached between the audio input vias on my mini-din breakout board and the audio tap point I mentioned near the RF modulator. I haven't noticed any humming in the audio that I've tested and thought it sounded pretty good actually.

 

Then again, I'm using a DC PSU to power my Intelly 2 as I don't have one of the original AC adapters for mine. That likely makes a difference here.

 

[the_crayon_king]

1 hour ago, -^CrossBow^- said:

I actually have the audio on my intelly 2 coming straight from the point where it was going into the RF modulator. I then have a 10µf cap attached between the audio input vias on my mini-din breakout board and the audio tap point I mentioned near the RF modulator. I haven't noticed any humming in the audio that I've tested and thought it sounded pretty good actually.

 

Then again, I'm using a DC PSU to power my Intelly 2 as I don't have one of the original AC adapters for mine. That likely makes a difference here.

 

I am using a DC adapter as well.

I'm not studied up in audio but the signal above has an AC signal on it. If you use a cap alone it will just remove the DC offset but that AC noise will remain. Setups might remove this noise but I have seen it on all model 2s. Haven't looked at the model 1 yet. One of those waveforms is going through a 100uf cap in the above picture and you can see the noise still present. 330mv of audio noise is faaaar too much.

 

I have lifted my audio pins 3, 4, and 38 in anticipation of mixing the audio from there.

The audio is normally all bridged together so I am just going to do that and put it through a potentiometer.

 

I might make a video on the difference or something as I suspect it will be day and night.

 

Edit--

I did the thing and it is noticeably better when going straight from the TV after lifting then reconnecting the pins; separate from the normal audio circuit.

 

This is the same signal captured twice. Once before the audio circuit of the intellivision and one after, The voltage can be lowered on the 3V one so never mind the voltage look at the waveform cause yikes.

 

These are the same sound at different voltages/places and you can see one is getting wrecked by 120hz noise. I am assuming TVs can filter some of this but that is way too much.

 

Edited April 16, 2021 by the_crayon_king

[the_crayon_king]

So my last post on audio until somebody makes a clarification (because I don't know jack about audio). Anyway I lifted those 3 pins tied them together then used 5K ohms to ground and that gave me roughly 2V p-p for audio. This looked fine on my oscope and sounded fine on my TV. I set out for 2V p-p off of the wikipedia entry for line level audio. The caveat here is that just because 2V is the highest I could see it doesn't mean its the highest that is possible. So if anybody knows of a particularly loud game that may help. 2V was reached when the shark appears on Shark! Shark!.

 

I would assume audio output needs to be buffered and then sent out under a specific impedance (like video) but I don't know anything about it. The daring among you can try this and report back.

 

Id like to make a pseudo stereo mod but for now just getting something passable for audio will suffice.

 

Ill open source some composite video/audio mod at some point and the audio circuit can be apart of that.

 

The circuit I am using is attached. It is very simple. I don't think this can hurt anything. Just lift the pins and attach them all together. The downside is that you will need to use a toggle switch or something if you want to have audio on RF. 

 

Ill look into composite again later.

 

 

Edited April 17, 2021 by the_crayon_king

[+-^CrossBow^-]

Thunder Castle has a tendency to sound distorted on most of the louder tunes that play in the game, at least on the model 1 units it does. 

 

Also, the guy that makes the stereo audio modification kits for the Vectrex is looking into adapting it for the Intellivision since they share the same sound chips more or less. Just an FYI that is being looked into.

 

[Reality Studio]

Just found this thread, definitely interested in buying this because my composite mod for my Intellivision 2 looks terrible. I have various upscalers including generic ones I got off Amazon, OSSC, Retrotink 2x Scart, and will definitely buy the Retrotink 5x once it's out. Also have an LTO Flash if that helps for testing. 

[the_crayon_king]

8 hours ago, Reality Studio said:

Just found this thread, definitely interested in buying this because my composite mod for my Intellivision 2 looks terrible. I have various upscalers including generic ones I got off Amazon, OSSC, Retrotink 2x Scart, and will definitely buy the Retrotink 5x once it's out. Also have an LTO Flash if that helps for testing. 

OSSC or Retrotink 5X will be the way forward for this or any of my other kits.

 

The newer board will have mild quality of life improvements. As a fallback I can still use the old boards with the new CPLD (same footprint). The newer CPLD is what makes the difference as far as sync correction/OSSC compatibility.

 

We are waiting for parts to come in. It could be a week it could be 2 months.

[+-^CrossBow^-]

I've shared this with @the_crayon_king already but thought I would show this in this thread as well since it is related.

 

I finished up installing the earlier board revision into my Intellivision 2 over the weekend. But as the RGB output was still giving me issues I decided to test the component output in more detail. Turns out that on a Retrotink2x Pro and through my Extron 7SC, that the component output works a lot better. On my Extron the video output is completely stable and looks to be noise free. On the Tink2x Pro, there are some odd flickering pixels of mainly white and red that appear throughout the image. Additionally there are still some instances where the video would drop out using the Tink2x Pro, although recovery from the dropouts and frequency was much less as opposed to RGB in my experience. 

 

Here is a direct video capture I took from the component (YUV) output of Crayon's older board from my intellivision 2 console along with some photos of my final installation. 

 

 

 

Here is the rear of the unit showing the outputs I installed. Due to the small size and lack of room honestly inside the Intelly 2, I used a 4 conductor TRRS jack + component breakbout dongle for the component connections. The L/R audio RCAs are for use with the component outputs as well and are just wired dual mono. The RGB output was installed in place of where the RF modulator used to be and uses a 9-pin Genesis 2 AV din for this. The toggle switch under the RGB is to switch between c-sync and sync on green. Sync on green isn't supported through my normal RGB setup, but does work more or less through my Tink2x SCART. This actually allowed for more stable video output with much fewer drop outs in this mode. But it comes at the cost that the Tink2x SCART doesn't actually handle this properly and as a result, everything has a more greenish tint or hue to it now than before. Still, it does offer a better way to play some of the games that causes issues otherwise. The old channel selector switch has been modified and now controls using the RGB or Component output from the board.

 

Here is the inside wiring that shows Crayon's board on the bottom of the console with all the needed wiring running mostly under neath the main board. Only the audio wires run on the top component side of the main board.

 

Here is my Intelly 2 setup when I was playing some games and testing. Yes I know that is a Sears controller in the center. I much prefer using that over the stock Intelly 2 controllers. Besides I only have one fully working Intelly 2 controller and that is in the player 2 spot currently. I also tend to add amber colored power LEDs on my intellivision systems as I think that color suits it more.

 

I've suggested to Crayon that his older boards if he decides to still sell them out for Intellivision use, be marketed for the component output side since at least in my case, that seems to provide much better and more stable results compared to the RGB output. I wish I had the same experience as others on the RGB output in this thread but I've tried two different boards and installed them into two different Intellivision models with the same consistent results. So for me he component is the way to go. But at least with the RGB in place, when the new boards come out that have the RGB improved, I can purchase one of them and swap it in place to test it. If the component output option is left intact on these newer boards, that would be a bonus as well.

 

[the_crayon_king]

The older boards have probably run their course. Unless they do something better than the newer ones I don't see a reason to sell both. The newer boards are coming mostly populated,. which saves me time and lets me use smaller parts. So I rather not do both specially when the newer boards will do YPbPr in addition to everything else.

The main difference between the two is the CPLD used. The new one is what is making all the difference here. I can still use the old CPLDs [same footprint] on the newer board design (for the other consoles this works for) so nothing really is going to waste here.

 

I will order the new boards within the week. If the boards beat the parts over here then I will short order the parts I need and get to making these again. I will test everything and post the results here.

 

I need to get a hold of some other 1st gen and 2cnd gen consoles. Anything that has less than 6 digital bits used to mix RGB into RF could probably be used with this kit (different code).

So far what I know can be made to work would be things like the Intellivision, O2, Arcadia, Aquarius. The Fairchild Channel F (maybe the first rev?) and the Game Gear are also possible (I don't see a point in making a game gear kit). 

 

If you guys can thing of any consoles that fall under that banner please let me know. Having 16 of less colors is a pretty big clue it might be able to work.

 

 

[+KylJoy]

On 4/21/2021 at 4:33 PM, the_crayon_king said:

If you guys can thing of any consoles that fall under that banner please let me know. Having 16 of less colors is a pretty big clue it might be able to work.

 

What about the Astrocade?  That would be sweet.

[the_crayon_king]

11 hours ago, KylJoy said:

 

What about the Astrocade?  That would be sweet.

I will be working on the Astrocade eventually. It needs a FPGA (this is a CPLD) or the Coleco RGB kit will probably work. I have gotten YPbPr out of the thing. So you can just convert that YPbPr to RGB without much extra effort. Both the Coleco and Bally use the LM1886 I think and both have YPbPr. Which is why I think the same kit could be used on both.

From what I briefly researched I didn't see too many other consoles that will work with this. I saw the Arcadia clones and that was about it.

 

@-^CrossBow^- So, I got Thunder Castle. While my video is not dropping out I do see that I am losing many frames on the second level. I will have to set up my logic analyzer and see what the heck it is doing around there. I don't have the time to compare my results with yours but I will look into it tonight. This very well may be something that will be solved by the new kit anyway.

It is actually going to be a pain to capture with the logic analyzer but I should get something out of it.

[the_crayon_king]

Ok, so good news/bad news.

The good news is this is does not seem to be an issue on the newer code/cpld.

 

I cannot for the life of me capture the issue on my logic analyzer. Whatever is causing the issue is probably only happening once per frame (wild speculation).

My thoughts are that the game/console is either not triggering sync when it should be or triggering sync when it shouldn't be. The codes are right out of the datasheet so... The other idea is that maybe the retrotink cannot handle the wonky sync the Intellivision puts out during certain screens.

 

V2 might be of particular importance. Changing sync to 1XXX1 (from 1XX01) might be all that is needed (will test that). If the issue isn't V2 then I don't think I will be able to fix the issue (on the old boards).

 

The reason this is not an issue with the newer code/cpld is that sync is regenerated using completely different bits/logic.

[the_crayon_king]

This is with the new code/CPLD:

 

[Lan Di]

On 2/12/2021 at 12:08 AM, the_crayon_king said:

Remove the ones in red if you have a genesis cable that has internal 75ohms.

I just installed this mod. I have Retro Gaming Cables Genesis 2 RGB SCART cable with internal 75ohms. I followed the above advice. I get an awesome picture. The problem is the picture does not stay. The title screen only stays up for a few seconds then it fades to black on every game. I tested the voltages and I get 5 volts at the AY-3-8915 chip. I tried two different power supply units and the same thing happens. It cannot be a power issue. Any advice? 

[+-^CrossBow^-]

4 hours ago, Lan Di said:

I just installed this mod. I have Retro Gaming Cables Genesis 2 RGB SCART cable with internal 75ohms. I followed the above advice. I get an awesome picture. The problem is the picture does not stay. The title screen only stays up for a few seconds then it fades to black on every game. I tested the voltages and I get 5 volts at the AY-3-8915 chip. I tried two different power supply units and the same thing happens. It cannot be a power issue. Any advice? 

I have the same cables and also use Insurrection Industries cables, and I have to leave the 75Ω in place or else I basically only get a very very dark picture. So in the case of this board on RGB, I have to leave the 75Ω in place in order to get a picture at all that I can use. It is a little darker than normal, but not enough to be that noticeable compared to my other systems in the AV setup.

 

So try putting those 75Ω back into place and see if that helps t all? I still get an unstable picture through RGB on my setup on anything but the cheap SCART to HDMI converter, but I do get a picture that I can see and work with. This is another reason I decided to wire mine up as component output instead as that seemed to provide me with a much more stable picture in my case.

 

I'm excited for the new boards though given the video capture above that @the_crayon_king posted.

 

[the_crayon_king]

Refer to this:

https://tinyurl.com/yekq89al

So 460mv is what you would have if you leave those resistors in AND have resistors in your cable.

690mv is what you would get if you have pulldowns but don't have resistors in your cable.
1.381V is what you get if you remove those 3 pulldown resistors but have a series resistor in your cable.

Keep in mind 700mv would be "perfect" so you should do whatever brings you closest to that.

 

I am assuming whatever device you are using is probably going into over voltage protection mode or something when you feed it anything over 1V.

 

Resistors in the SCART head (for anything besides maybe sync) is a bad idea anyway.

I wonder if there is a way to go back and delete that post since that information is wrong.

 

 

 

 

[CPUWIZ]

You can edit the original post now.

[the_crayon_king]

Update:

 

The boards I ordered will be here on May 6th. 

However, there is a tiny error [wrong part selection] in the buffer section (my fault) so I will have to order another batch. I like to use placeholder parts and I forgot to switch it if anyone is curious as to what happened.

 

Anyway, when I get the boards on the 6th I will still be able to validate the design for the final version of this by bodging the correct part in.

Assuming everything else on the board is good to go (besides the buffer) then I should be able to put in another order and have it no later than the end of the month.

 

What has been added on the new boards:

level shifter (mostly to deal with clock and allow everything to run off 3.3V). The level shifter will also allow higher voltage inputs (up to 6.5V [safer]).

split ground planes to isolate digital and analog circuitry [noise].

OSSC compatibility (a true sync fix).

Two completely different color pallets (before it was just a few colors changed)

removed redundant or unneeded parts/switched everything to smaller components

added EXT pin for a yet undecided function.

 

Because of the spacing I plan to add a NTSC encoder that floats underneath this board.

The NTSC encoder would allow for composite and s-video. Composite and S-video would only work over RGB.

This NTSC encoder would be an addon board and not needed if you just want RGB or YPbPr. The composite/S-video should be cleaner than any other composite/s-video mod on the market since it is made from the source itself not the messy RF signal.

 

The final version will look like this assuming I don't need to make any further changes.

Despite appearances this is smaller than the old board.

 

Absolute worst case scenario I can populate the old boards with the new CPLD/code.

I could start making the old boards with the new CPLDs soon if anyone is in a great hurry.

I am not sure if there will be any functional difference between the two layouts new vs old.

 

Edited May 3, 2021 by the_crayon_king

[+-^CrossBow^-]

1 hour ago, the_crayon_king said:

Update:

 

The boards I ordered will be here on May 6th. 

However, there is a tiny error [wrong part selection] in the buffer section (my fault) so I will have to order another batch. I like to use placeholder parts and I forgot to switch it if anyone is curious as to what happened.

 

Anyway, when I get the boards on the 6th I will still be able to validate the design for the final version of this by bodging the correct part in.

Assuming everything else on the board is good to go (besides the buffer) then I should be able to put in another order and have it no later than the end of the month.

 

What has been added on the new boards:

level shifter (mostly to deal with clock and allow everything to run off 3.3V). The level shifter will also allow higher voltage inputs (up to 6.5V [safer]).

split ground planes to isolate digital and analog circuitry [noise].

OSSC compatibility (a true sync fix).

Two completely different color pallets (before it was just a few colors changed)

removed redundant or unneeded parts/switched everything to smaller components

added EXT pin for a yet undecided function.

 

Because of the spacing I plan to add a NTSC encoder that floats underneath this board.

The NTSC encoder would allow for composite and s-video. Composite and S-video would only work over RGB.

This NTSC encoder would be an addon board and not needed if you just want RGB or YPbPr. The composite/S-video should be cleaner than any other composite/s-video mod on the market since it is made from the source itself not the messy RF signal.

 

The final version will look like this assuming I don't need to make any further changes.

Despite appearances this is smaller than the old board.

 

Absolute worst case scenario I can populate the old boards with the new CPLD/code.

I could start making the old boards with the new CPLDs soon if anyone is in a great hurry.

I am not sure if there will be any functional difference between the two layouts new vs old.

 

Awesome! I've already got one of your older boards that was sent to me to be installed into a model 2. I've done so strictly in YUV output for this client and advised them that in the future, if they wish, it could be sent back to me and have the newer version board installed in place of the older and then separate RGB with a toggle switch added at that time. But they are in a hurry, so I'm going to be shipping out this component output only intelly2 likely tomorrow.