Atari 2600 CleanComp Composite Mod - Feedback & Testing

[+x=usr(1536)]

Just occurred to me: the PCB basically has edge connectors set at (I believe) 2.54mm pitch, which is pretty standard.  Have you looked into the possibility of using card connectors to wire up to the board?  On TIA-less machines (or ones where the TIA isn't the primary video generator - 7800, CX-55, A8s, for example), it's going to be necessary to find a way to mount it that isn't soldering directly to the TIA itself, and may help with mounting.

 

I realise that in order for this to be workable there are components that would need to be relocated in order for the card connector to have enough material to bite onto.  Not looking at this as a must-have by any means, but it could simplify installation in a number of machines.

[+Al_Nafuur]

On 10/25/2022 at 10:26 AM, retrosix said:

Yep. Like this. Then we will be selling Composite and S-Video 1.8 meter cables with bar wire ends on the other side, for easy soldering to the mod.

I would suggest to put the contacts for the cable away from the edge. Then no one can accidentally short something outside the board with the soldering end of the cable.

 

e.g.:

[+Stephen]

What a cool looking board - I'd be interested in at least one, but it sounds like you already have enough testers and I am not in a hurry to install one (unless you are still in need of testers - but it doesn't sound like it).

[radventure]

Indicating interest in a board once they are tested up. I have an ntsc light sixer that that I'd love to get composite and s-video from

[retrosix]

16 hours ago, x=usr(1536) said:

Just occurred to me: the PCB basically has edge connectors set at (I believe) 2.54mm pitch, which is pretty standard.  Have you looked into the possibility of using card connectors to wire up to the board?  On TIA-less machines (or ones where the TIA isn't the primary video generator - 7800, CX-55, A8s, for example), it's going to be necessary to find a way to mount it that isn't soldering directly to the TIA itself, and may help with mounting.

 

I realise that in order for this to be workable there are components that would need to be relocated in order for the card connector to have enough material to bite onto.  Not looking at this as a must-have by any means, but it could simplify installation in a number of machines.

I can certainly work on the shape once I have opened up and played with more versions. Right now I've only focused on the 2600. Usually my stuff sells out in a month anyway at most and I am always improving and then ordering new versions. So this first version I have already allocated 50 to testers and ordered another 200 for sales. Once I get the feedback and look at more versions of the consoles I can possibly make a universal one.

 

My only concern is, I have perfected this one to timings within 5 nanoseconds on things like the internal gate logic delay of the TIA and the order the LUMA pins get output, to get the sharpest edges. I cannot see other versions of consoles (7800 for example) having this exact identical filtering, timing and cleanup required. So I imagine a version per console to really get the best image from them all. But until I explore that, or you guys test for me, I won't know. 

[retrosix]

15 hours ago, Al_Nafuur said:

I would suggest to put the contacts for the cable away from the edge. Then no one can accidentally short something outside the board with the soldering end of the cable.

 

e.g.:

Yes at the moment I just want ot make sure across at least all versions of 2600 we have room to move the board outside of the TIA. If not yes I can move those pads into the board at least. Will do that on next version

[retrosix]

15 hours ago, Stephen said:

What a cool looking board - I'd be interested in at least one, but it sounds like you already have enough testers and I am not in a hurry to install one (unless you are still in need of testers - but it doesn't sound like it).

Can never have too many. Once they land next week I'll test on NTSC and so long as it works on my NTSC and its clean enough I will announce the expected quality of this board with photos/videos etc..., planned improvements if this board isn't perfect, and then for everyone to email me their details for shipping test units out. I could even just make it free on the website and you just order, limited to one per customer. That will actually make it much easier.

[+-^CrossBow^-]

13 hours ago, retrosix said:

Can never have too many. Once they land next week I'll test on NTSC and so long as it works on my NTSC and its clean enough I will announce the expected quality of this board with photos/videos etc..., planned improvements if this board isn't perfect, and then for everyone to email me their details for shipping test units out. I could even just make it free on the website and you just order, limited to one per customer. That will actually make it much easier.

That is very cool of you to do this! If I were to get one for testing, I would be testing it in a vader or H6 with only temporary outputs on it. Just enough to get direct captures from the composite and s-video to send over as needed.

 

[retrosix]

New boards in, I will solder them up next week, test on the NTSC version too and then list them for £1 on my site (easiest way than manually gathering everyones addresses, manually booking in labels etc.. that way they can just be packed like all regular orders and go out nice and fast. I will limit it to 1 per customer on the checkout but if you want a few you can leave comments on the order and I can see if I have enough.

[retrosix]

The new design I made had a footprint error, just being remade now, should have them in 5 days. So slight delay but will keep you posted once ready to buy and test

[cwilkson]

I really like your 2 write ups.  So many of these 2600 mods just kind of hack around and shove stuff together until they get something that "works".  But it looks like you put real effort into studying the stock circuitry and finding weaknesses and defects and possible solutions.  Great job!  There are still a couple of things for you to find once you get this pass tested but most of the things you've already tried to address.

 

Where are you located?  Are you trying to make a PAL mod?  (I noticed your reference to COL phase shifting on alternate lines.)  Also....Pditfall is supposed to be green not blue! 

The PAL version especially interests me.  Seems like there are a couple of things that would be easier to fix if you had alternating chroma phase available.  I dabbled, but never really dived into it.

 

When you get it done I would be really interested to see how it stacks up against mine.  And at which level.  I made several back in the day, ranging from "pitiful hack" to Prosumer to VGA output.  I also had an HDMI version mostly worked out but I became disillusioned with the hobby and walked away.

 

EDIT:

PS.  Be careful reducing the pull up resistors.  The output transistors were designed for about 1.5 mA of sink capability.  You can create local hotspots on the die!

Best case...nothing happens.

Realistic case #1...The pulldowns won't go all the way "low".  You may have sync issues, or image dependent luma levels.  And if you use CMOS buffers they'll run hotter than they should as their inputs approach VCC/2.

Realistic case #2...(less likely, but possible)...Those local hot spots may affect your COL delay chain => unwanted color shift that is image dependent.

Bad case...(unlikely, but still!  It's bad!)....The hots spots are bad enough to cause your semiconductor junctions to blur and the transistors will stop working over time.  The TIA is dead from this.

 

Just be careful.

Edited November 21, 2022 by cwilkson

[+batari]

Cool concept, as the dangling wires to the TIA pins can be problematic.

 

However, is there any reason why you aren't using a castellated board instead? It seems to me that this would allow for MUCH easier soldering, especially for a novice. I am sure you could fit the output pads on the sides as well, as I agree with the poster who cautioned against having them so close to where you solder to the TIA from the underside.

[macsonny]

On 11/4/2022 at 1:34 AM, retrosix said:

New boards in, I will solder them up next week, test on the NTSC version too and then list them for £1 on my site (easiest way than manually gathering everyones addresses, manually booking in labels etc.. that way they can just be packed like all regular orders and go out nice and fast. I will limit it to 1 per customer on the checkout but if you want a few you can leave comments on the order and I can see if I have enough.

Any way these can be purchased in Australia?

 

[retrosix]

Sorry for the delay. Got 20+ of these out to people on our discord and who order from us. So far they all have them working and like the quality which is good.

 

Personally I'm still not absolutely happy with the quality and feel I can improve, but I also feel at this stage its good to get much wider feedback.

 

I have 5pcs left so those who feel they can test S-Video and Composite (not just one) and will be critical of the quality, ideally on both CRT and LCD, email me your address to contact@retrosix.co.uk and the first 5 I will post out tomorrow or as soon as I get the addresses.

 

I will make a production run after CNY once factories re-open and sell this one, as its clearly good enough based on current feedback and has worked on every variation of 2600 from 6, 4, Jr, Pal and NTSC etc... then I will sell v1 still with the desire to get feedback from everyone on improvements.

 

Also on that note, after 2600 what would you like to see next? 5200, 7800.. something else? I plan to make composite mods for most consoles using this same technique of completel reconstructing the signal, and have already some improvements I can do on this one but all the things learned will go towards improving the next versions

[retrosix]

On 11/21/2022 at 9:20 PM, cwilkson said:

I really like your 2 write ups.  So many of these 2600 mods just kind of hack around and shove stuff together until they get something that "works".  But it looks like you put real effort into studying the stock circuitry and finding weaknesses and defects and possible solutions.  Great job!  There are still a couple of things for you to find once you get this pass tested but most of the things you've already tried to address.

 

Where are you located?  Are you trying to make a PAL mod?  (I noticed your reference to COL phase shifting on alternate lines.)  Also....Pditfall is supposed to be green not blue! 

The PAL version especially interests me.  Seems like there are a couple of things that would be easier to fix if you had alternating chroma phase available.  I dabbled, but never really dived into it.

 

When you get it done I would be really interested to see how it stacks up against mine.  And at which level.  I made several back in the day, ranging from "pitiful hack" to Prosumer to VGA output.  I also had an HDMI version mostly worked out but I became disillusioned with the hobby and walked away.

 

EDIT:

PS.  Be careful reducing the pull up resistors.  The output transistors were designed for about 1.5 mA of sink capability.  You can create local hotspots on the die!

Best case...nothing happens.

Realistic case #1...The pulldowns won't go all the way "low".  You may have sync issues, or image dependent luma levels.  And if you use CMOS buffers they'll run hotter than they should as their inputs approach VCC/2.

Realistic case #2...(less likely, but possible)...Those local hot spots may affect your COL delay chain => unwanted color shift that is image dependent.

Bad case...(unlikely, but still!  It's bad!)....The hots spots are bad enough to cause your semiconductor junctions to blur and the transistors will stop working over time.  The TIA is dead from this.

 

Just be careful.

Thanks for the feedback, drop me your email if you want one sending got a few left.

 

It buffers all signals instantly now without any change to pull ups or anything altered on original console whatsoever, along with quite a lot more things. Still room for improvement also.

 

I am thinking about the chroma shifting/delay circuit also. Perhaps a variable inductor would be enough to delay the chroma to allow shifting? Or do you have other ideas. Definitely good to get feedback. I feel there is still room for improvements, but good to go to first release.

[cwilkson]

On 1/7/2023 at 8:34 AM, retrosix said:

Thanks for the feedback, drop me your email if you want one sending got a few left.

 

It buffers all signals instantly now without any change to pull ups or anything altered on original console whatsoever, along with quite a lot more things. Still room for improvement also.

 

I am thinking about the chroma shifting/delay circuit also. Perhaps a variable inductor would be enough to delay the chroma to allow shifting? Or do you have other ideas. Definitely good to get feedback. I feel there is still room for improvements, but good to go to first release.

I sent you a PM.

 

I'm not sure what you mean with the chroma shift and inductor.  What's the exact issue you're trying to solve there?  And how?

Maybe pictures are the best way to explain:

1. Show the problem on the existing waveform.
2. Show how you'd like to modify the waveform.
3. Show your proposed schematic fix.

 

[retrosix]

 

Did some updates, added option for stereo audio (for NTSC), added tuneable chroma voltages as some monitors prefer different levels or personal preference for saturation, cleaned up the signal even more so works on even really cheap upscalers nicely, removed more noise and over/undershoots etc... 

 

So its in production now for version v1.0 and then any feedback we can improve next version.

 

Should be on website in 4 weeks approx.

[macsonny]

1 hour ago, retrosix said:

 

Did some updates, added option for stereo audio (for NTSC), added tuneable chroma voltages as some monitors prefer different levels or personal preference for saturation, cleaned up the signal even more so works on even really cheap upscalers nicely, removed more noise and over/undershoots etc... 

 

So its in production now for version v1.0 and then any feedback we can improve next version.

 

Should be on website in 4 weeks approx.

What's the website?

[retrosix]

RetroSix.co.uk. Will be in Retro Consoles then Atari 2600 when out. 

 

Price is in it will be £22 plus taxes 

[+x=usr(1536)]

@retrosix' preproduction CleanComp board arrived earlier this week, and is now in the machine.  This was actually the second time that it was installed: there was an earlier pass taken at it last night, but I wasn't satisfied with the way that it ended up.  Some poor cabling decisions were made during that attempt which were totally my fault and nothing to do with the CleanComp itself, so starting over from scratch made sense.

 

Installation was in an NTSC 2600 Jr. with a date of manufacture on the PCB of 0886.  A/V cable used was 8BitClassics' Atari XL/XE 5-Pin DIN S-Video & Composite AV Cable, which I like because it has both composite and S-Video connectors.  Overall the job was very straightforward, though I did forget one thing that I'll mention at the end since it's easy to overlook.  Feel free to try to spot it before then 

 

First step: solder on your A/V cabling before installing the board to the TIA; it makes things much easier to work with.

 

 

Just a quick closer look at the board with the A/V wiring attached.  The heat shrink is there for strain relief more than anything else.  I'll come back to the cabling a bit later.

 

 

Soldered in place:

 

 

A closer look at the board as attached to the TIA.  There's more than adequate space to easily reinstall the RF shield:

 

 

And the end result.  Since this is a fairly tatty Junior with plenty of case damage, I just ran the A/V cabling out through one of the larger holes on the corner above the power switch.

 

 

However, I'll be doing this job a third time at some point.  That also comes back to the A/V wiring, which I wanted to run through the square hole in the case visible below the vents in the bottom of the shell, but couldn't.  Again, that will be covered shortly:

 

 

About the A/V wiring: had the correct size of DuPont connectors been on hand, I would have used them on the edge of the CleanComp board for the A/V connections rather than soldering the wires directly to the pads.  This would have allowed for the A/V cable to be removable when working on the machine, which right now it's not.  That's not a problem because of the case damage allowing the A/V cable to be routed in ways that it normally couldn't be, but on a machine with an intact shell it could be a problem.  For reference, I only had 2.54mm / 0.10" connectors on hand; a smaller size is needed.

 

Now for the thing that I forgot, and remembered at the first powerup after installation:

 

 

Neither the PAL nor NTSC jumpers had been selected   Entirely my fault as, being dissatisfied with the A/V cabling last night, I never fired it up - which meant that I had a brain fart and completely forgot to check on this before reassembly, as evidenced by the earlier photos.

 

Having bridged the NTSC pads as shown below:

 

 

This is what I was greeted with on the next boot:

 

 

Bugger.

 

Actually, though, this is a good thing: this particular machine has had varying degrees of flakiness in the power switch, DC jack, and RF connector ever since it was given to me.  I also found rust on the voltage regulator when it was opened up, which suggests water ingress at some point and gives some ideas as to why the power switch has never really responded to chemical cleaning.

 

Since the CleanComp is showing the same display problems as with RF, my suspicion is that it's time to replace components.  Order already placed with Console5, and I'll update once I've had a chance to R&R the various bits and pieces that are known to be flaky.

[+-^CrossBow^-]

I installed my preview version of the Cleancomp into my NTSC 2600jr this evening finally. Results are mixed but I do like how easy it is to install the board. It looks like the actual production versions are a tad wider and have actual vias to solder onto the TIA pins with? That is good because the solder pad only solution on these earlier made ones requires to basically just blob the solder onto the bad and pins to get them to attach well. Here are some pics of my install into my jr. I didn't quite go full no cut but and I decided to just use composite output for what will be a test bench console anyway for now. But I did connect up the s-video temporarily to capture this shot of pitfall. The colors look good and everything is pretty sharp but the output has bad vertical bars across the entire image. Composite has it as well but it isn't quite as pronounced as what s-video shows.

 

 

 

 

 

As I reused the RF jack for my composite, I only had to run 2 wires from the output board since ground is already attached to the old jack. The 3.5mm jack has the ground tab soldered to the side of the RCA jack and also only needed the single wire as these preview version boards are mono output only.

 

[+x=usr(1536)]

On 2/12/2023 at 8:48 PM, x=usr(1536) said:

Since the CleanComp is showing the same display problems as with RF, my suspicion is that it's time to replace components.  Order already placed with Console5, and I'll update once I've had a chance to R&R the various bits and pieces that are known to be flaky.

Having replaced the voltage regulator, power jack, and RF jack in addition to recapping the Junior, there's no change in video output.  The picture quality is improved, but the same graphical glitches still appear.

 

My suspicion at this point is a flaky TIA.  Plan is to remove the CleanComp, socket the chips, swap in a known-good TIA, then reinstall the CleanComp and see where things stand.  Won't be getting to that until sometime during the week, however.

[+x=usr(1536)]

Problem resolved.  The luma and chroma outputs on the A/V cable were soldered on backwards at the CleanComp, making S-Video look terrible and composite merely bad by comparison due to (I assume) backfeeding.  Whether I misread the silkscreen around the pads, reversed the wires, or got a cable with the usual wiring colours swapped over, I have no idea.  In any event, here's the end result:

 

Composite:

 

 

S-Video:

 

 

The potato shots make it difficult to tell, but sharpness is improved over S-Video compared to composite.  Composite does look really nice, though.

 

And the TIA got socketed earlier today as well; that was actually what got the bells ringing in my head about the possibility of having luma and chroma reversed.  In any event, the machine got a good going-through that I'd been putting off and it needed regardless, so it worked out in the end.

[retrosix]

On 2/18/2023 at 7:43 AM, -^CrossBow^- said:

I installed my preview version of the Cleancomp into my NTSC 2600jr this evening finally. Results are mixed but I do like how easy it is to install the board. It looks like the actual production versions are a tad wider and have actual vias to solder onto the TIA pins with? That is good because the solder pad only solution on these earlier made ones requires to basically just blob the solder onto the bad and pins to get them to attach well. Here are some pics of my install into my jr. I didn't quite go full no cut but and I decided to just use composite output for what will be a test bench console anyway for now. But I did connect up the s-video temporarily to capture this shot of pitfall. The colors look good and everything is pretty sharp but the output has bad vertical bars across the entire image. Composite has it as well but it isn't quite as pronounced as what s-video shows.

 

 

 

 

 

As I reused the RF jack for my composite, I only had to run 2 wires from the output board since ground is already attached to the old jack. The 3.5mm jack has the ground tab soldered to the side of the RCA jack and also only needed the single wire as these preview version boards are mono output only.

 

Those lines definitely not normal. Can you do a video while also turning the Atari's color wheel? Looks like what happens when you put an NTSC game in a PAL console or vice versa, and the chroma timing is out.

[retrosix]

Some updates on the production unit.

 

1. Added support for Stereo audio out for NTSC consoles (no auto switching yet, just solder blob)

2. Removed any loading of TIA pins so zero load on anything on TIA

3. Separated circuit completely for Chroma and Luma until final stage (had a small bit of chroma noise (40mV) mixing into Composite and S-Vid V channels due to mixing inside IC)

4. Plated through hole solder now for easier install

5. Larger and more separated cable pads

6. Adjustable chroma level to balance perfectly with your console, TV and cable, as well as tune out noise or saturate to your preference

7. Support for cheap upscalers (images below)

 

For upscalers the image looked really bad. On normal TVs and CRTs totally fine, but pass through an upscaler or capture card it was much worse. So I spent a lot of time really improving that.

 

Top of image is pre-production unit (green), bottom is production unit.

 

 

And here is pacman on an LCD that shows any issues up the most (I used the harshest monitor I could find that produced the worst visuals to perfect the image as much as possible). 

 

 

These are both composite, S-Video is even nicer.

 

Should be 2 weeks out from being in stock. Then further feedback definitely welcome and anything I can improve on.

 

Will make 7800 version after this I guess.