Any Adam RGB video options?

[+videofx]

I am looking for RGB video out option for my Adam. Anything going?

 

Thanks!

[Falonn]

There are three known solutions, but none of them are perfect.

 

The graphics chip used in the Colecovision and Adam outputs relatively standard component (YPbPr) video with one quirk: during line blanking, it includes a "color burst" signal on the blue line (and also red in the PAL version) that is normally only seen in composite video signals.  Presumably this was to make it more convenient for the RF and composite outputs to do their job, but it makes things less convenient for clean RGB out.

 

That color burst signal has a tendency to upset the automatic level detection in modern RGB receivers so that they think blue can go lower than zero, which means black is no longer black.  Everything gets a blue cast and generally looks pretty bad.

 

Solution 1: There is an old Texas Instruments application note ("TMS9928/29 and TMS9128/29 Interface to Color Monitors") that shows a circuit that can do RGB out.  They admit in the text of the document that they're not focused on accurate color output, which is already one strike against it.  Worst of all: it does nothing to solve the "too much blue" problem.

 

Solution 2: Citrus3000psi created ColecoRGB (current at version 1.2), which is a tiny board that can conveniently be soldered right on the back of the graphics chip.  It was presumably based on the RGB circuit in the Baby Pac-Man arcade unit, which also uses the same graphics chip.  This one solves the "too much blue" problem by throwing the baby out with the bathwater and clipping the bottom of the signal off.  Whenever there is a transition from black to another color, that pixel gets mostly cut off, leading to very thin vertical lines and text that is barely legible.  The colors aren't great, either.

 

Solution 3: 256byteram released the TMS9929A RGB and Component adapter at Hackaday.  This one solves the "too much blue" problem in a more clever way and is generally pretty passable.  The color isn't perfect, but the only real downside is that some of the specified components in the circuit have been discontinued and are no longer available.

 

Sample screenshots and lots more information about all of that can be found in the other topic where you posted.  We've been testing and building these things over there for a couple months now to try and see each of their strengths and weaknesses.

 

I feel like we're getting close to a 4th solution that would keep all the pros and omit all the cons above.  It's a hobby project I've been working on in my evenings, so I couldn't possibly give a proper release date, but I want to say it's less than a month or so out.  (I'm going to regret that sentence.  )

[TPR]

I have F18a installed in my ADAM that works pretty well. I know those aren't available anymore but if someone might have a spare laying around?

[Ruggers Customs]

3 hours ago, Falonn said:

It's a hobby project I've been working on in my evenings, so I couldn't possibly give a proper release date, but I want to say it's less than a month or so out.  (I'm going to regret that sentence.  )

No regrets homie, I have faith in that last sentence!

[Tursi]

6 hours ago, TPR said:

I have F18a installed in my ADAM that works pretty well. I know those aren't available anymore but if someone might have a spare laying around?

MK2 is almost ready, Matt's been sharing a lot of updates lately.

 

[emmanuelf]

You forgot the citrus3000psi ColecoRGB PAL

And for XR8052, you have plenty of possible replacements : From AD you have AD8052, AD8042, ADA4891-2, AD8062

I don't see why is is "passable".

All these suffer proper video output buffering. But you discovered these recently with the magic of THS7374 and his integrated LPF

[Falonn]

Citrus3000psi's ColecoRGB PAL is just a verbatim copy of 256byteram's circuit from Hackaday (with a required component missing and a typo) and no attribution given that I've ever seen.  So I'd rather give the credit to 256byteram.

 

I suppose to be fair, Citrus' board would be easier to install... assuming you are able to correct for that missing capacitor and aren't tricked by the double R27 labels.

[+videofx]

I have waited this long so another month or 2 is no big deal.

 

The reason I brought this up is look at the output of my Aux output. Its super noisy but my composite is pretty good. See my pic below:

 

 

 

Any way to fix the Aux output until we get the RGB solution?

 

Thanks!

 

[emmanuelf]

Yes, but proper routing and mechanical design is an art too, it is a valuable part of the final result. As this is a pure disinterested unfinished work giveaway, I assume that the original attribution and credit is a simple unintentional  omission.

For the missing capacitor and labeling value error, the design was clearly marked as "Untested, use at own risk".

To be complete and for the record, don't miss the R25 BoM value error: R25 must be 680R and not 680K.

 

With a little bit of shifting/rerouting to add a THS7374 at the output, and some values tuning, this is the best price/quality compromise.

LMH1251 is very costly, a pain to integrate with most pin unused and really overkill for the limited colorspace of the TMS.

 

[Falonn]

21 minutes ago, emmanuelf said:

... don't miss the R25 BoM value error: R25 must be 680R and not 680K.

That was eventually corrected on the OSHPark page, so I don't count that mistake anymore.

 

23 minutes ago, emmanuelf said:

With a little bit of shifting/rerouting to add a THS7374 at the output, and some values tuning, this is the best price/quality compromise.

The "ColecoRGB PAL" board was already pretty full.  With another IC, it might get tricky fitting it all under the VDP's footprint.

 

In large quantities, I agree that the price wouldn't make as much sense to include an LMH1251, but for the kinds of short/medium runs this board will see, I bet it will at least end up in the same ballpark.  I'm not sure the ~$5 difference would mean much to someone that wants to add RGB out to their beloved, forty year old system.

 

58 minutes ago, videofx said:

The reason I brought this up is look at the output of my Aux output. Its super noisy but my composite is pretty good.

So... I don't know very much about the Adam.  I just poked around the user manual and the schematic.  Are they just calling the RF port "Aux" to make a distinction between the composite out?  They both output the same signal, right?

 

In that case, the RGB out would supersede them both.  (Sorry for my lack of experience!  If those ports do something different, the answer will also be different.) 

 

You mentioned that the composite out looked good, so the workaround in the meantime is probably "use the composite output instead of RF".

[+videofx]

2 minutes ago, Falonn said:

That was eventually corrected on the OSHPark page, so I don't count that mistake anymore.

 

The "ColecoRGB PAL" board was already pretty full.  With another IC, it might get tricky fitting it all under the VDP's footprint.

 

In large quantities, I agree that the price wouldn't make as much sense to include an LMH1251, but for the kinds of short/medium runs this board will see, I bet it will at least end up in the same ballpark.  I'm not sure the ~$5 difference would mean much to someone that wants to add RGB out to their beloved, forty year old system.

 

So... I don't know very much about the Adam.  I just poked around the user manual and the schematic.  Are they just calling the RF port "Aux" to make a distinction between the composite out?  They both output the same signal, right?

 

In that case, the RGB out would supersede them both.  (Sorry for my lack of experience!  If those ports do something different, the answer will also be different.) 

 

You mentioned that the composite out looked good, so the workaround in the meantime is probably "use the composite output instead of RF".

 

The Aux out is supposed to be higher quality composite and it also supplies the audio also which you cant get on the Adam just using composite. So since my picture is crap I am using composite out for the picture and the aux out to get audio

[ChildOfCv]

9 hours ago, videofx said:

 

The Aux out is supposed to be higher quality composite and it also supplies the audio also which you cant get on the Adam just using composite. So since my picture is crap I am using composite out for the picture and the aux out to get audio

I guess you're talking about the round DIN connector?  I see an instructable about that, at least.

Electrically, this is exactly the same connection as the composite video output.  So if composite is good but the aux port is not, it's either the cable or the DIN plug, either of them are not making good contact.

[+videofx]

3 minutes ago, ChildOfCv said:

I guess you're talking about the round DIN connector?  I see an instructable about that, at least.

Electrically, this is exactly the same connection as the composite video output.  So if composite is good but the aux port is not, it's either the cable or the DIN plug, either of them are not making good contact.

 

The cable I am using is commercially made so I don't think its the cable. but I have a brand new console I will try and if its the same problem then its the cable. Otherwise its the DIN on the console and I will just have to wait for the RGB solution.

 

Unless you have other ideas?

[NIAD]

The Adam has 3 video outputs all tapped from the CV Delta Board:

 

1) RF

2) Monitor - this is Composite Video only using a standard Compsoite connector

3) Auxillary - this is Composite Video and Audio using a 7-pin DIN connector

 

The video for the Auxillary port is tapped from the Monitor port wiring so your issue could be in this wiring “tap” especially since wires used are not up to snuff as far as gauge used and insulation is minimal. Of course, the DIN connector or DIN Monitor Cable could be the issue, but my best guess would be the wire that is tapped from the Monitor Port and connects to the Auxillary DIN connector.

[+videofx]

OK, I just found something interesting. I tired a brand new Adam console and the video still produces the same noise as my other console.

 

Now what interesting is I remove the cable and insert the male DIN on my cable to just touching the pins on the female DIN connector on the Adam console then the video is rock solid. The video doesn't go to crap until I push the male DIN all the way in.

 

Any ideas?

[ChildOfCv]

It does sound like a cable issue then.

 

Even commercial manufacturers biff it.  I had a Hauppauge TV card for my computer that came with a remote control receiver on a cable.  The remote didn't work.  I chopped up the rubber housing around the remote sensor and discovered that one of the wires wasn't connected.  Soldered it on, and then the remote worked.