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Falonn

TMS-RGB: An RGB Mod for 2020 and Beyond

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Back with another Coleco question. I just installed the TMSRGB in another CV, and it tested fine with my temporary 8 pin RGB set up. I tried using a Sega Genesis 9 pin style connector, which a 9 pin to SCART cable from Console5 to test the system, and now I have what appears to be a ground issue. I tried changing the TMSRGB's ground wire to a couple different spots with no luck. Reflowed solder on all TMSRGB pads, reflowed on the ground of the 9 pin connector, and nothing. The composite mod board is outputting a correct signal and works fine through my TRRS jack. The 9 pin cable works with other consoles. What could be going on? Thanks.

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Edited by Ianr757

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Looks like a sync issue to me.  Is the SCART connected directly to the TV?  Does the cable have internal resistors that the 8-pin test did not?

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10 hours ago, Ianr757 said:

Back with another Coleco question. I just installed the TMSRGB in another CV, and it tested fine with my temporary 8 pin RGB set up. I tried using a Sega Genesis 9 pin style connector, which a 9 pin to SCART cable from Console5 to test the system, and now I have what appears to be a ground issue. I tried changing the TMSRGB's ground wire to a couple different spots with no luck. Reflowed solder on all TMSRGB pads, reflowed on the ground of the 9 pin connector, and nothing. The composite mod board is outputting a correct signal and works fine through my TRRS jack. The 9 pin cable works with other consoles. What could be going on? Thanks.

154273114_774997069784269_5166123610258339760_n.jpg

 

 

 

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Can't really see the TMS board with the way you have the wires routed. And I'm not sure what cable you might be using with your setup. I use a Genesis 2 SCART cable from Insurrection Industries specifically for c-sync on my setup and it works great through my OSSC. 

 

I didn't wire a ground from the TMS to the 9-pin because it wasn't needed with the entire housing soldered down to the edge of the PCB like you did. You have the ground tabs soldered onto your breakout board on the connector so again you have the ground covered soldering the entire thing to the PCB.

 

Where did you route the audio from? I just took my audio straight off where C88 but it looks like yours is wrapping back behind and under?

 

But yeah as long as your outer housing on the 9-pin you are using is soldered down to the PCB you very likely have the ground taken care of and don't need a ground wire off the TMS output back to the 9-pin. 

 

Wanted to mention that if you removed the 75Ω resistors off the output section on the TMS-RGB and if you already have composite installed. Wire the composite output to the cvid point on your 9-pin and you can use HDRetrovision cables as well as SCART RGB.

 

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3 hours ago, ChildOfCv said:

Looks like a sync issue to me.  Is the SCART connected directly to the TV?  Does the cable have internal resistors that the 8-pin test did not?

Thanks for replying. The SCART cable goes into a Retrotink RGB2COMP then into component on my Toshiba consumer CRT. I am not sure about what is contained within the 9 pin cable. The 8 pin cable, for clarity, is from Tim Worthington's NESRGB kit.

 

3 hours ago, -^CrossBow^- said:

Can't really see the TMS board with the way you have the wires routed. And I'm not sure what cable you might be using with your setup. I use a Genesis 2 SCART cable from Insurrection Industries specifically for c-sync on my setup and it works great through my OSSC. 

 

I didn't wire a ground from the TMS to the 9-pin because it wasn't needed with the entire housing soldered down to the edge of the PCB like you did. You have the ground tabs soldered onto your breakout board on the connector so again you have the ground covered soldering the entire thing to the PCB.

 

Where did you route the audio from? I just took my audio straight off where C88 but it looks like yours is wrapping back behind and under?

 

But yeah as long as your outer housing on the 9-pin you are using is soldered down to the PCB you very likely have the ground taken care of and don't need a ground wire off the TMS output back to the 9-pin. 

 

Wanted to mention that if you removed the 75Ω resistors off the output section on the TMS-RGB and if you already have composite installed. Wire the composite output to the cvid point on your 9-pin and you can use HDRetrovision cables as well as SCART RGB.

 

I'll check out the Insurrection cable, thank you. The audio is coming from the bottom of C88. I wasn't getting audio from the top so I just moved it under and it seemed to work. Thanks for the help.

 

Should I assume it is a cable problem? This cable (from Console5) works just fine with my JVC X'Eye. Maybe I should wire up the composite on the breakout in case the cable is trying to use composite for c-sync?

Edited by Ianr757

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Well I can't answer in regards to which cable you have, but I've done this install a few times myself now and it is pretty straight forward. The only thing I have to do different, is that if I'm using HDRetrovision cables, then I have to install a composite upgrade in addition and wire the composite out to the CVID input on the 9-pin mini dins I use. I also have to remove the 75Ω resistors off the output side of the TMS-RGB and then bridge the pads together. It will work with the resistors in place, but has a darker picture than it should.

 

And as I stated, I don't wire anything off the GND output off the TMS-RGB because the entire outer housing of the 9-pin mini dins I use (I get them from Console5) are already attached to the ground on the breakout board I use. I just have to make sure as you did, that I have the center and both sides soldered in place on the breakout board. Solder the outer housing of the mini din to the ground on the CV board and you are grounded about as well as you can get in something like this. Easiest way to test that is to see if you have continuity from the GND off the outer casing from the cable plugged in to anywhere along the outer edge of the CV PCB. I'd guess that the GND pad off the output from the TMS is also attached to ground and you could test that also.

 

But it does look to be a sync issue so again, if you have a composite AV in place as well, try wiring it up to the cvid point on your breakout board. It won't hurt anything and would even allow you to use genesis 2 composite output cables from it also if needed.

 

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5 hours ago, -^CrossBow^- said:

Wanted to mention that if you removed the 75Ω resistors off the output section on the TMS-RGB and if you already have composite installed. Wire the composite output to the cvid point on your 9-pin and you can use HDRetrovision cables as well as SCART RGB.

Yeah, looks like cables meant for the Genesis 2 already have 75-ohm resistors (and also capacitors) built in on the R, G, and B connections.  They do not expect a resistor at all on the CSYNC.  So at the very least all 4 of those resistors should be removed and bridged on the TMS-RGB for that.

It's weird that you need the composite video though.  The TMS-RGB seems to output the correct csync voltages on the CSYNC 75 pin that he's using.

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2 hours ago, -^CrossBow^- said:

Well I can't answer in regards to which cable you have, but I've done this install a few times myself now and it is pretty straight forward. The only thing I have to do different, is that if I'm using HDRetrovision cables, then I have to install a composite upgrade in addition and wire the composite out to the CVID input on the 9-pin mini dins I use. I also have to remove the 75Ω resistors off the output side of the TMS-RGB and then bridge the pads together. It will work with the resistors in place, but has a darker picture than it should.

 

And as I stated, I don't wire anything off the GND output off the TMS-RGB because the entire outer housing of the 9-pin mini dins I use (I get them from Console5) are already attached to the ground on the breakout board I use. I just have to make sure as you did, that I have the center and both sides soldered in place on the breakout board. Solder the outer housing of the mini din to the ground on the CV board and you are grounded about as well as you can get in something like this. Easiest way to test that is to see if you have continuity from the GND off the outer casing from the cable plugged in to anywhere along the outer edge of the CV PCB. I'd guess that the GND pad off the output from the TMS is also attached to ground and you could test that also.

 

But it does look to be a sync issue so again, if you have a composite AV in place as well, try wiring it up to the cvid point on your breakout board. It won't hurt anything and would even allow you to use genesis 2 composite output cables from it also if needed.

 

 

37 minutes ago, ChildOfCv said:

Yeah, looks like cables meant for the Genesis 2 already have 75-ohm resistors (and also capacitors) built in on the R, G, and B connections.  They do not expect a resistor at all on the CSYNC.  So at the very least all 4 of those resistors should be removed and bridged on the TMS-RGB for that.

It's weird that you need the composite video though.  The TMS-RGB seems to output the correct csync voltages on the CSYNC 75 pin that he's using.

All right, I put composite onto the breakout for the 9 pin and it works. I had heard of composite being used as the sync before, but never ran into a need for it myself. Thanks for all the help.

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2 hours ago, ChildOfCv said:

Yeah, looks like cables meant for the Genesis 2 already have 75-ohm resistors (and also capacitors) built in on the R, G, and B connections.  They do not expect a resistor at all on the CSYNC.  So at the very least all 4 of those resistors should be removed and bridged on the TMS-RGB for that.

It's weird that you need the composite video though.  The TMS-RGB seems to output the correct csync voltages on the CSYNC 75 pin that he's using.

Only HDRetrovision cables require the composite signal for them to get Sync from. Why they aren't using actual C-sync I have no idea but it is in the FAQs of their website that they aren't using c-sync/sync they require composite sync from a composite signal. I recently ran into this issue with a 32x that I had added s-video to and had to remove the composite from the 32x in order to prevent issues with the s-video that was installed. Then I find out HDretrovision cables don't work and I had to restore the composite video back into the thing using the Genesis composite video input to do it.

 

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@-^CrossBow^- Also, thank you for that very useful Youtube video on installing the CV RGB using the 9 pin mini DIN. It was where I got the inspiration for the mod you see here, haha.

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19 hours ago, -^CrossBow^- said:

Only HDRetrovision cables require the composite signal for them to get Sync from. Why they aren't using actual C-sync I have no idea but it is in the FAQs of their website that they aren't using c-sync/sync they require composite sync from a composite signal. I recently ran into this issue with a 32x that I had added s-video to and had to remove the composite from the 32x in order to prevent issues with the s-video that was installed. Then I find out HDretrovision cables don't work and I had to restore the composite video back into the thing using the Genesis composite video input to do it.

 

I suppose one possibility is that the CSYNC output of the 1881 doesn't just separate the sync signals, but gives a solid sync during vertical retrace, or something like that.

@Falonn  Well, one idea for a V3 design might be to include jumpers for the SYNC input to the final amps, to come from either the 1881 or the Y signal.

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23 hours ago, -^CrossBow^- said:

Only HDRetrovision cables require the composite signal for them to get Sync from. Why they aren't using actual C-sync I have no idea...

Yeah, I think Ruggers ran into the same thing during his initial testing.  For whatever reason they get their sync from the composite video pin instead of the dedicated C-sync pin.

 

4 hours ago, ChildOfCv said:

Well, one idea for a V3 design might be to include jumpers for the SYNC input to the final amps, to come from either the 1881 or the Y signal.

It's just that the cable is looking at the "wrong" pin.

 

In a 9-pin, Genesis-style installation, you can go one step farther and have your cake and eat it too if you also install the typical composite mod.  It ends up looking like the usual set of connections for a 9-pin TMS-RGB install except pin 4 goes to the composite mod instead of the TMS-RGB board.  That configuration works with all cables: Genesis RGB, Genesis composite, HD Retrovision, or whatever else you might have.

 

1 hour ago, Ianr757 said:

Another quick question. Will this mod still function if I install the 5v RAM mod? 

TMS-RGB only touches things that are already 5V.  It should be completely independent of the 5V RAM mod.

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48 minutes ago, Falonn said:

In a 9-pin, Genesis-style installation, you can go one step farther and have your cake and eat it too if you also install the typical composite mod.  It ends up looking like the usual set of connections for a 9-pin TMS-RGB install except pin 4 goes to the composite mod instead of the TMS-RGB board.  That configuration works with all cables: Genesis RGB, Genesis composite, HD Retrovision, or whatever else you might have.

The last two I've done, I've installed composite kits into the CV, ran the composite out from the kit to pin 4 on the 9-pin, and still ran a wire from sync off the TMS-RGB to pin 5 on the 9-pin. That is how my personal CV is wired up and it seems to work with everything including the HDRetorovision cables this way. But you are saying that just running composite to pin 4 only on the 9-pin din is enough for all cables to work? 

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1 hour ago, -^CrossBow^- said:

But you are saying that just running composite to pin 4 only on the 9-pin din is enough for all cables to work? 

Nope, what you said is exactly correct.  You just did a better job of saying it than I was able to! :D  Doing it that way (with pin 4 and pin 5 both connected to useful signals) means you reach maximum compatibility with just about everything.

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On 8/23/2020 at 5:54 PM, Retro_Game_Lover96 said:

Hey guys, I’ve gotten the RGB board installed on my TI 99 after replacing the 9918 chip with 9928 chip, but I have this stupid B&W screen. :(

 

B2009144-104E-45DA-B7A8-2A60F5804C97.jpeg

Hi, I own an TI-99/4A european version (with TMS9928) and after installing the citrus3000 mod I get the same picture than you (B&W). Did you finally succedd with TMS-RGB?

 

 

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6 hours ago, Papalapa said:

Hi, I own an TI-99/4A european version (with TMS9928) and after installing the citrus3000 mod I get the same picture than you (B&W). Did you finally succedd with TMS-RGB?

 

 

Did you replace the resistors?  Look at this thread.  



The citrus3000 mod ought to work too, but even the TMS-RGB only works after you've modified the TI.

EDIT:  Oh wait... I remember that the c3000PSI "PAL" version forgot an important capacitor.  So you may have to do some PCB surgery on that mod board, or get the TMS-RGB.

Edited by ChildOfCv

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13 hours ago, ChildOfCv said:

Did you replace the resistors?  Look at this thread.  



The citrus3000 mod ought to work too, but even the TMS-RGB only works after you've modified the TI.

EDIT:  Oh wait... I remember that the c3000PSI "PAL" version forgot an important capacitor.  So you may have to do some PCB surgery on that mod board, or get the TMS-RGB.

Many thanks for the information but my TI 99/4A is already european version so, I guess that no resistors modification will be necessary to install the mod. Anyway, I'll try this way.

Edited by Papalapa

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Having done a few of these mods now, and also having recently tried out an old component mod by 8bitdomain which left a lot to be desired, I'm wondering, is there any way to do an RGB to YPbPr conversion inside the console itself, kind of like the kit available for the NESRGB? 

 

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Because it's clean/standard RGB out, there shouldn't be anything preventing additional conversions.  (This isn't internal to the console, but something like the RetroTINK RGB2COMP should work right out of the box.)

 

That said, the TMS-RGB is already doing a YUV-to-YPbPr-to-RGB conversion.  So if you wanted component out, the Right Thing wouldn't be adding an additional conversion, but circumventing the LMH1251 chip in the middle of the board (which is responsible for the YPbPr-to-RGB half) instead.

 

Because that one is responsible for about half the cost of the whole board (and because YPbPr doesn't require separate sync lines, meaning you can remove a few more components), a stand-alone "TMS-YPbPr" board could be smaller, simpler, and cheaper.  It probably wouldn't be as popular as the RGB board--more like the TMS-RGB's "little brother" or something like that--but I've had the thing half-routed and almost ready to test for something like six months now.  It's one of those projects I keep trying to find the time for, but life keeps getting in the way. 😕

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Posted (edited)

@Falonn I hear you about real life keeps getting in the way 😩  I still would love to work with you on the component video board.  I really want to be able to take your component video schematic once it's available and design a PCB with the same footprint and mounting design as 5-11under's board.  That way anyone with 5-11under's board can easily upgrade to the new board (me included).

 

999745260_5-11underPCB.thumb.png.37a494218df11f474a747881a07ddc5a.png

 

But then it'd be great to finalise the CV palette project beforehand and so I have made a start on writing this up and will send it to you for review (if that's okay) when I have something worthwhile for you to look at. 

Edited by Ikrananka

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Yep, coordinating with you is also on that same to-do list. :D  (Testing the corrected palette is the very first step once I get the still-assembled TMS-RGB breadboard converted over to YPbPr.  I'd love to take a look at what you've got written up.)

 

The board I was talking about routing would be the same kind of compact, "right on the back of the VDP" thing as the TMS-RGB, so your idea of a drop-in replacement for existing installs using the 5-11under form factor is still a useful idea with plenty of work you'll get to do. :D  Outside of the connectors, I expect both form factors will end up with a near-identical BOM.  So, anyone that wanted to build a TMS-YPbPr themselves could just pick the PCB shape that works best for their situation and then buy a "universal" set of components for it.

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1 minute ago, Falonn said:

Yep, coordinating with you is also on that same to-do list. :D  (Testing the corrected palette is the very first step once I get the still-assembled TMS-RGB breadboard converted over to YPbPr.  I'd love to take a look at what you've got written up.)

 

The board I was talking about routing would be the same kind of compact, "right on the back of the VDP" thing as the TMS-RGB, so your idea of a drop-in replacement for existing installs using the 5-11under form factor is still a useful idea with plenty of work you'll get to do. :D  Outside of the connectors, I expect both form factors will end up with a near-identical BOM.  So, anyone that wanted to build a TMS-YPbPr themselves could just pick the PCB shape that works best for their situation and then buy a "universal" set of components for it.

Very early on the write-up so will be a few months I suspect before I've found time to get it to a state for you to look at.

 

I love that idea for the PCB options with "universal" components 👍

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7 hours ago, Falonn said:

Because it's clean/standard RGB out, there shouldn't be anything preventing additional conversions.  (This isn't internal to the console, but something like the RetroTINK RGB2COMP should work right out of the box.)

 

That said, the TMS-RGB is already doing a YUV-to-YPbPr-to-RGB conversion.  So if you wanted component out, the Right Thing wouldn't be adding an additional conversion, but circumventing the LMH1251 chip in the middle of the board (which is responsible for the YPbPr-to-RGB half) instead.

 

Because that one is responsible for about half the cost of the whole board (and because YPbPr doesn't require separate sync lines, meaning you can remove a few more components), a stand-alone "TMS-YPbPr" board could be smaller, simpler, and cheaper.  It probably wouldn't be as popular as the RGB board--more like the TMS-RGB's "little brother" or something like that--but I've had the thing half-routed and almost ready to test for something like six months now.  It's one of those projects I keep trying to find the time for, but life keeps getting in the way. 😕

Thanks for the information! Well, once you have some time for it, I would love to get one to try out. Just let me know please!

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