Ultimate Atari 7800 mod list?

[+MrZarniwoop]

I'm busy re-living my childhood while dreading this coming winter, and wanted to refurbish an "ultimate" Atari 7800.

 

Is this a complete list of the recommended replacements and mods?

 

• remove RF components (or should it be best left alone just in case?)
• install TBA's Ultimate Atari Video (UAV) board kit
• install new S-Video, composite, and audio jacks (modifying the plastic case)
• replace OS chip (with PAL/Asteroids upgrade)
• replace power jack (with standard barrel, plus new standard 1A power supply... maybe the Jaguar one?)
• replace LED (with blue)
• replace VRM
• replace capacitors (3)
• replace button switches (4)

 

Am I missing anything?

[+-^CrossBow^-]

You don't have to replace out the original power port. There are other options that would allow you to use a standard barrel jack without trying to force a different power plug in there. You can make a cable adapter similar to what I was selling about 2 months back. Or you can wire in the barrel jack, and have it hang out the back but connect it in parallel to the original so that either one can be used.

 

What were you looking to do in regards to the VRM side?

 

Also I see you have the gold s-video jack listed from console5. Were you planning to match the RCA outs with gold plated as well? I've a warning about that but maybe I'm the only one that has ran into issues using them.

 

[+MrZarniwoop]

28 minutes ago, -^CrossBow^- said:

You don't have to replace out the original power port. There are other options that would allow you to use a standard barrel jack without trying to force a different power plug in there. You can make a cable adapter similar to what I was selling about 2 months back. Or you can wire in the barrel jack, and have it hang out the back but connect it in parallel to the original so that either one can be used.

 

What were you looking to do in regards to the VRM side?

 

Also I see you have the gold s-video jack listed from console5. Were you planning to match the RCA outs with gold plated as well? I've a warning about that but maybe I'm the only one that has ran into issues using them.

 

Good point regarding the power port. I think I like the idea of a cable adapter leaving a good port as stock.

 

VRM concern is that they seem to fail more than other parts and it's a proactive refurbish. Same with the switches and recap.

 

I assumed either all gold or all nickel video/S-Video jacks, although hadn't considered mixing them. Were your issues from gold jacks or mixing metals?

[+-^CrossBow^-]

I was just curious on the VRM if you were going to replace with new or something a bit different like I offer on the consoles I've upgraded over the past few years.

 

My issue with the gold plated connectors isn't the mixing metals. It is the fact that the gold plated jacks are not as durable on the screw threads as the standard nickel ones. I have had issues when installing the gold plated jacks that it is very easy to over tighten them and the threads break along the circumference of the jack as a result thereby rendering it useless. So it is more difficult to use them and tighten them enough where they won't slip over time. In many cases, I would advise that if you want the gold plated jacks and their bling, to tighten them until they seem snug and then have to result to epoxy around the edges to hold it all in place. Even with star washers it can be tricky to get them tight enough without the threads breaking. Nickel jacks seem to be much sturdier as I've not had the issue happen with those. I'm sure it could just be the gold plated RCA jacks that I've gotten in to use and there are better options but the ones from console5 suffer this as do the ones that seem to come included with some AV kits I've purchased over the years. So extra care is needed when installing them is all I'm saying.

 

[+MrZarniwoop]

What do you differently with the VRM?

 

Excellent tip regarding the gold connectors!

[+-^CrossBow^-]

I offer two option for my clients when servicing the 7800s and honestly most consoles.

 

I either replace the original VR with a 2A output rated version to ensure there are no potential power issues. This was somewhat brought up due to the XM add in module. The other option that is of course much more expensive from a parts cost but works very well in the 7800s and most other consoles, is to replace the standard VR with a DC-DC switching regulator. I specifically use the Traco 2-2450 model. It is a drop in replacement 2A output switching regulator with built in filtering to help with noise and seem to have a longer warranty than most of these do. They also offer a wider variety of input voltages they can accept. But at $10+ each depending on bulk pricing, they aren't a cheap upgrade. But the advantage is that the 7800 will literally draw half of the required current from the PSU it normally would making the entire setup much more efficient and the switcher regulator doesn't build up any real heat so the heat sink can be completely removed and results in much less heat build up in the console internally as a result. Now there is still considerable heat coming off the main IC chips, but not enough to be a concern as the original VRs do.

 

 

[+MrZarniwoop]

22 minutes ago, -^CrossBow^- said:

replace the standard VR with a DC-DC switching regulator. I specifically use the Traco 2-2450 model. It is a drop in replacement 2A output switching regulator with built in filtering to help with noise and seem to have a longer warranty than most of these do. They also offer a wider variety of input voltages they can accept. But at $10+ each depending on bulk pricing, they aren't a cheap upgrade. But the advantage is that the 7800 will literally draw half of the required current from the PSU it normally would making the entire setup much more efficient and the switcher regulator doesn't build up any real heat so the heat sink can be completely removed and results in much less heat build up in the console internally as a result. Now there is still considerable heat coming off the main IC chips, but not enough to be a concern as the original VRs do.

That's a great suggestion, I had not seen that before.

 

Is there anything else you do for clients or missing from my list above?

[+-^CrossBow^-]

I replace all the switches if any one of them is flaky. They are cheap enough and I offer two different types. The OEM style that are cheap and more premium grade switch that costs a little more each but in bulk isn't too bad.

 

The RF Modulator does NOT have to be removed if you are installing the UAV. But what you do have to do if you want the audio to still work from both, is add in extra resistors and output filter cap to the audio output jacks you decide to use.

 

I'm assuming you are planning to do all of these yourself so you might look for my install guide on the UAV for the 7800 I wrote up sometime ago. I believe TBA still has a local link for this they use and provide to their customers. Only thing is that I never updated the guide to include the use of the extra resistors to keep the RF audio intact. My guide the way it is written will still give you good quality audio, but at the expense of no audio from the RF out. I really..really need to redo that portion or at least add it as an addendum option.

[John Stamos Mullet]

If you are planning on using physical carts for the potentially incompatible 2600 Activision games Robot Tank, Space Shuttle, Decathlon, and the Star Path Supercharger, rather than a multicart/SD cart like a Harmony cart - then you would probably want to remove capacitor C64* from the board, located on the right hand side between the ICs.

 

 

*if it exists, depending on your board revison. Earlier models do not have this circuit, so no compatibility issues with these games.

[+-^CrossBow^-]

Good point, as I actually do that by default on the systems sent to me when I find it installed. However, I can confirm that disabling the circuit will not only cause Dark Chambers for the 2600 to no longer work (In most cases), but it will also break Kung Fu Master on the 2600. So if either of those are important to you then perhaps installing a switch to turn it on/off is a thought. But most people would rather play the 7800 versions of those games anyway and so those two games (possibly others I've not encountered) aren't a huge loss compared to the other games that work again without it.

 

[the Goat]

On 11/11/2020 at 9:04 AM, MrZarniwoop said:

• install TBA's Ultimate Atari Video (UAV) board kit

Will there ever be an RGB mod for the 7800?

[+MrZarniwoop]

Just now, the Goat said:

Will there ever be an RGB mod for the 7800?

I am curious about how French (PAL) SCART 7800s drive RGB. I’ve read it’s derived from luma/chroma (S-Video) sources.

[CPUWIZ]

On 11/11/2020 at 6:04 AM, MrZarniwoop said:

install TBA's Ultimate Atari Video (UAV) board kit

 

Did they clone the UAV, or did they get permission?   I may have missed something.

[+MrZarniwoop]

“These boards were developed by Bryan Edewaard and sold by him for a long time.  He has now sold the rights for the rev. D version to The Brewing Academy and we are producing them for all machines.”

I think they pay him a royalty.

[+-^CrossBow^-]

2 hours ago, CPUWIZ said:

 

Did they clone the UAV, or did they get permission?   I may have missed something.

TBA bought the design and rights from Bryan to make and sell UAV boards going forward. Been that way for well over a year now I think? Only real difference is that they have Macrorie's logo on them vs the old Predator UAV drone logo they used to have.

 

[juansolo]

7 hours ago, MrZarniwoop said:

I am curious about how French (PAL) SCART 7800s drive RGB. I’ve read it’s derived from luma/chroma (S-Video) sources.

It does, it won't be pleasant...

7 hours ago, the Goat said:

Will there ever be an RGB mod for the 7800?

Both Tim Worthington and Saint have mentioned working on an RGB mod for the 7800. It's a complex beastie to do and I suspect the demand for it will be super low (even more so than the 2600 RGB mod), it'll be magnificent if it happens. But I wouldn't hold out for one. You could always add it later if it happens.

[+-^CrossBow^-]

3 hours ago, juansolo said:

It does, it won't be pleasant...

Both Tim Worthington and Saint have mentioned working on an RGB mod for the 7800. It's a complex beastie to do and I suspect the demand for it will be super low (even more so than the 2600 RGB mod), it'll be magnificent if it happens. But I wouldn't hold out for one. You could always add it later if it happens.

This is a good point in that it can be done at a later time when these options become available. However, I'm pretty content with the s-video I get from the 7800 honestly. I have the means to use RGB but in several cases I've found the s-video output to be well enough for me and enjoy the game.(SNES, Jaguar, DC come to mind).

 

And I have to wonder how that will effect color on 7800 games also. We already know that palette switches are needed for the NES and I think the 2600 RGB mods now. Even the RGB being worked on for the Intellivision will have two different palette options to choose from since some of the colors as produced through RF are due to artifacting and not 100% reproducible through these RGB upgrades without effecting other colors also. So yeah I can see it being a very tricky beast to tame.

 

[+MrZarniwoop]

What about stereo? Is that a thing on a 7800? Maybe for 2600 games?

[CPUWIZ]

I made an Alexa & Universal IR Remote thingy, that can control the IR-LED and all 4 buttons of the 7800 as well, all via voice or Alexa App.  It actually is running through WeMo to get to Alexa, but that is another story, I just know it works for me.

 

Oh, there is also an added expansion port and a multi BIOS selector in the pic.  Pretty much all my 7800's are naked, because I like to fondle them.  The buttons are also brand new and I added stand off's to the motherboard.

 

 

[+MrZarniwoop]

19 minutes ago, CPUWIZ said:

expansion port

What’s on the expansion port?

[CPUWIZ]

27 minutes ago, MrZarniwoop said:

What’s on the expansion port?

 

Wires.

[+-^CrossBow^-]

7 hours ago, MrZarniwoop said:

What about stereo? Is that a thing on a 7800? Maybe for 2600 games?

Yes and no. The TIA on the NTSC model does have the two separate audio channels and could be wired for left/right stereo. However, the external audio line from the cartridge port that is used for Pokey and other sound chip add on games is a single audio channel and therefore mono only. I personally am not a fan of the stereo mod since the audio on screen doesn't follow the action correctly. Sure in the game combat player 1 sounds come from the left and player 2 come from the right, but when player 1's tank or plane is on the right side of the screen, the audio still comes from the left. I just find that it sounds off and again not a fan personally. With the pokey audio line being mono you end up having to connect that to the right or left and again just doesn't good to me overall.

 

 

[+MrZarniwoop]

1 hour ago, -^CrossBow^- said:

Yes and no. The TIA on the NTSC model does have the two separate audio channels and could be wired for left/right stereo. However, the external audio line from the cartridge port that is used for Pokey and other sound chip add on games is a single audio channel and therefore mono only. I personally am not a fan of the stereo mod since the audio on screen doesn't follow the action correctly. Sure in the game combat player 1 sounds come from the left and player 2 come from the right, but when player 1's tank or plane is on the right side of the screen, the audio still comes from the left. I just find that it sounds off and again not a fan personally. With the pokey audio line being mono you end up having to connect that to the right or left and again just doesn't good to me overall.

 

 

What if left/right was wired with POKEY audio on both channels, but with a mono/stereo switch? Homebrew stereo games would still work but most of the time you’d leave it in mono mode.

[+-^CrossBow^-]

Pokey on both channels doesn't seem to mix in properly doing it that way at least not without some distortion. In regards to stereo and homebrews, besides Skeleton+ what else actually made accurate use of the of the two separate TIA channels?

 

[+MrZarniwoop]

1 hour ago, -^CrossBow^- said:

Pokey on both channels doesn't seem to mix in properly doing it that way at least not without some distortion. In regards to stereo and homebrews, besides Skeleton+ what else actually made accurate use of the of the two separate TIA channels?

 

Excellent points. I have to imagine there’s a way to get at 2-channel TIA and mix it with POKEY audio without distortion, although it may not be straightforward.

 

From the thread I linked earlier, it noted:

 

2-channel directional audio (panning on homebrews)

A-VCS-ET Challenge

Medieval Mayhem

Skeleton+

 

2-channel polyphonic audio (original design intent was two speakers in the console)

Boulder Dash (instruments on different channels)

Combat (player 1 left/player 2 right)

Pitfall 2 (melody left/beat right)

Solaris (different sounds on different channels per YouTube video)

Star Fire (instruments on different channels)

Thrust+ (instruments on different channels)

... apparently other early games if the thread is correct

 

 

Could 7800 homebrews get at 2-channel TIA audio? If not, then this is limited to 2600 games, which is still interesting if going for an “ultimate” set of mods.