UAV - Ultimate Atari Video - Atari 7800

[+-^CrossBow^-]

Are people saving the RF modulators to repair 7800s in the future? I ran into that on a Coleco that needs the RF to work to Mod the video. No RF = no video.

 

Well in the case of the 7800, the RF modulator isn't needed at all for the AV mods that exist for it. Having said that I do usually keep the RF modulators in place and working when I've done AV mods on the 7800 for clients. I've got a few of the 7800 RF modulators saved and on hand from those that didn't want them though on hand. I also save the RF modulators from 5200s when I've been requested to remove those doing AV mods.

 

But you are correct in that the standard composite AV mods for the CV do require the RF modulator to be somewhat functional. I guess only the FA18 mod wouldn't car since that completely replaces the video circuitry in the process.

Edited June 4, 2019 by -^Cro§Bow^-

[John Stamos Mullet]

Just put my UAV in my 7800 yesterday using this guide - perfect!

 

I reused the RF box for the video composite connection. Just desoldered and removed the board from it.

[ChildOfCv]

 

Well in the case of the 7800, the RF modulator isn't needed at all for the AV mods that exist for it. Having said that I do usually keep the RF modulators in place and working when I've done AV mods on the 7800 for clients. I've got a few of the 7800 RF modulators saved and on hand from those that didn't want them though on hand. I also save the RF modulators from 5200s when I've been requested to remove those doing AV mods.

 

But you are correct in that the standard composite AV mods for the CV do require the RF modulator to be somewhat functional. I guess only the FA18 mod wouldn't car since that completely replaces the video circuitry in the process.

 

I wonder if some of the UAV could be used to completely replace the modulator for the CV though? After the analog switch you get Y, Pb, and Pr, which can *almost* be sent directly to the component input on TVs that have it (you just get a bluish hue for everything due to the TMS method of inducing color burst). But if the chip that he uses takes those inputs directly, it could work.

[John Stamos Mullet]

So here's something:

 

UAV video looks great, except... Some 2600 games have rolling horizontal bars. H.E.R.O. in particular has them really bad, completely distracting. Other 2600 games are completely fine and have no rolling bars.

 

7800 games don't appear to have them at all, and even if I turn the TV's brightness all the way up - they are barely perceptible. - but this same 7800 had no rolling bars when it had a standard two resistor/transistor mod in it. (although it had other distracting interference.

 

What say ye?

 

New Caps? (already changed the 7805 VR) Something wonky in HERO?

 

For an example this is what I'm seeing (not my video but same thing):

 

[+DrVenkman]

Well, it's not an issue with the HERO game or PCB itself - my copy is fine in through my 7800 and UAV:

 

 

 

 

It's possible you have a grounding issue with the TIA color pot, perhaps. Other 2600-specific causes might be bad connections at one or more of the TIA luma pins, or the TIA Color signal into the UAV. If your TIA is socketed you might try removing and reseating it.

 

[John Stamos Mullet]

Well, it's not an issue with the HERO game or PCB itself - my copy is fine in through my 7800 and UAV:

 

IMG_1617.JPG

 

IMG_1619.JPG

 

 

It's possible you have a grounding issue with the TIA color pot, perhaps. Other 2600-specific causes might be bad connections at one or more of the TIA luma pins, or the TIA Color signal into the UAV. If your TIA is socketed you might try removing and reseating it.

 

heh. Figured it out.

 

Took the whole damn thing apart at work and re-soldered all the joints to the various access points on the motherboard just before the resistor ladder and it looked gorgeous on a spare TV we have laying around the office.

 

Took it home... whomp whomp. Same issue. Then I remembered - it's going through a component video switchbox to the tv because the TV only has one composite input and no S-Video.

 

Plugged it in directly - perfect. So it was my shitty radio shack switcher introducing interference, not the 7800.

 

Funny thing is - my Sega Genesis and Master System both also go through that switchbox, and do not have the rolling bars, but they are also standard spec composite video, not modded - right out of the 6 pin DIN port.

 

Now I have to try to re-situate the switchbox somewhere it won't get interference, or just junk it and deal with swapping cables when I want to switch consoles.

 

Thanks for the help, all!

[SoundGammon]

On 5/29/2017 at 12:07 AM, -^CrossBow^- said:

 

That is the color bleed effect I'm talking about and while I also didn't fire up Ms. Pac-man, I would imagine it to look clean through the UAV.

It does look great through the UAV! No color bleed!

[christo930]

While I am probably in the minority here, unless the RF modulator is really bad and the picture is greatly suffering because of it (in which case it probably should be fixed first), these games are low resolution and meant to be viewed in RF on a CRT TV.  A lot of 2600 games in particular look terrible on a modern LCD screen.  Though I have never played these old games on actual LCD TVs, I am told they frame buffer and there is time lag between what is on the screen and what the actual machine is doing and all of the problems that causes.  I'm not saying I am opposed to them and there are reasons people might not be able to maintain a dedicated CRT TV for gaming, like space considerations.    But generally I just think they look terrible on LCD screens. The sharpness of s-video usually isn't great for 2600 games either.

[ApolloBoy]

It's not just for the sake of playing these systems on a flatscreen, even on a CRT the UAV just blows the stock video output away. Heck, even using composite out on my UAV-modded 7800 through an external RF modulator (connected to an RF-only CRT) beats the snot out of the internal RF.

[+DrVenkman]

The internal RF on both my  7800's look like ass. Just awful. By contrast, the stock RF on my 5200 looked pretty great, but finally adding a UAV to it this past winter still made a great improvement. Composite through a good-condition CRT is - to me - the perfect way to enjoy these games. However, if (when) my current crop of CRTs goes kaput, I'll use my RetroTink 2X-Pro or whatever the current flavor of the month might be for scan-doublers that allows me to continue to enjoy my systems, even if my TV's and monitors have all gone to the great Tube Farm In the Sky. If an LED is all I have, I will make do but I'm glad I don't have to. But even if I did, I still wouldn't use RF for a minute longer than I have to. 

[envytomdead2]

For longest time I considered this mod but would occasionally read random things about an occasional game that didn't work after the mod. Since I have had my 7800 since I was 10 years old, I decided to buy a second 7800 that already had the mod. Everything looks beautiful through my RetroTink. All of my 7800 games work fine as do most 2600 but I am starting to have more 2600 titles that do not work. Just a black screen on clean carts that work in my OG 7800 and my retron 77. My original 7800 is the one with expansion port, this modded one does not have it so it's a later model. What's weird all the 2600 games that don't work so far are later ones Kung Fu Master, Dark Chambers and Double Dragon. I can getDouble Dragon to boot for a bit but I can not start the game. The reset button doesn't work and then it eventually goes black. Is it the mod or the 7800 itself? To me it seems weird that these later day games would be the ones causing me issue as they came out after the 7800 was on the market. 

[+-^CrossBow^-]

The UAV doesn't change anything in the logic of the 7800 at all. It just takes the video signals that are already being passed through the RF and outputs them through a replacement video encoder. 

 

Have you tried these newer released 2600 games on your older 7800 with the expansion port?

 

2600 Dark Chambers has issues with the earlier units or some version just after as an additional timing circuit was added by Atari into the 7800 to allow the 2600 version of Dark Chambers to work. However, this same change in the 7800 design can also cause some Activision games to not work. Besides the UAV, the only other modification that I've done and others have done, is to disable C64 from circuit to disable this extra timing circuit. That will cause 2600 dark chambers to no longer work on that particular 7800 but will allow the Activision titles that didn't work before to work again. Far as I've been able to test, disabling C64 only affects the 2600 version of Dark Chambers. I've been told that Stargate is also affected by it, but Stargate works fine on the 7800s that I've done it to. But that is the only modification I'm aware of that would change anything in the 7800 behavior and in this case it is to restore games that didn't work previously at the expense of just the one of which, there is a better version of for the 7800 anyway.

 

[envytomdead2]

5 hours ago, -^CrossBow^- said:

Have you tried these newer released 2600 games on your older 7800 with the expansion port?

Yes they all work on my older 7800 with the expansion port. Other activision titles do work on the modded system Pitfall!, keystones kapers, kaboom, boxing and commando.

[+DrVenkman]

8 hours ago, envytomdead2 said:

For longest time I considered this mod but would occasionally read random things about an occasional game that didn't work after the mod. Since I have had my 7800 since I was 10 years old, I decided to buy a second 7800 that already had the mod. Everything looks beautiful through my RetroTink. All of my 7800 games work fine as do most 2600 but I am starting to have more 2600 titles that do not work. Just a black screen on clean carts that work in my OG 7800 and my retron 77. My original 7800 is the one with expansion port, this modded one does not have it so it's a later model. What's weird all the 2600 games that don't work so far are later ones Kung Fu Master, Dark Chambers and Double Dragon. I can getDouble Dragon to boot for a bit but I can not start the game. The reset button doesn't work and then it eventually goes black. Is it the mod or the 7800 itself? To me it seems weird that these later day games would be the ones causing me issue as they came out after the 7800 was on the market. 

I’ll echo what @-^CrossBow^- says: the UAV doesn’t change a thing about the 7800 - it just intercepts video signals before they go to the RF modulator and create a nice, super-clean set of chroma, luma and composite signals, without changing the stock RF at all unless you disconnect or remove the RF modulator (which I did on my daily-driver 7800 when I installed a UAV).

 

I’m going to focus on the bolded part I quoted above. Is this something that just started? As in, these games used to work on this machine and now don’t? Or what exactly? Because it sounds more to me like you might be developing an issue with the cart connector on your 7800. My AT84 serial number 7800 has a pretty worn set of connector pins. I was having a lot of issues with games not wanting to load, and yes, lots of them were Activision 2600 games. I took a wooden toothpick and manually bent the 7800 connector pins one at a time to be closer together to improve the spring tension a bit, and I cleaned the absolute hell out of the then with electrical contact cleaner. 

 

After all that, the machine started working much better with those troublesome Activision titles, though I’d still have to remove and reinsert some games a few times once in a while. The ultimate solution would be to replace the cart connector complete at some point, though I’ve never done it. My UAV-modded machine is an A1 serial number machine, and it’s never had a similar problem. Both machines have an expansion port installed, though the A1 system came in a case without the the opening for it. Good job, Atari.  

Edited June 6, 2020 by DrVenkman
typos

[envytomdead2]

1 hour ago, DrVenkman said:

As in, these games used to work on this machine and now don’t? Or what exactly

Sorry I should have worded that better.  The modded 7800 is a new purchase. These carts have never worked on this new 7800. I'm still in the process of testing my entire library on the new machine. If these aren't issues that happen with UAV mod, then it just must be the 7800 itself. The main thing is that it plays all of my 7800 titles, which it does. Any problem 2600 titles can either be played on my old 7800 or Retron 77. 

[+-^CrossBow^-]

5 hours ago, envytomdead2 said:

Sorry I should have worded that better.  The modded 7800 is a new purchase. These carts have never worked on this new 7800. I'm still in the process of testing my entire library on the new machine. If these aren't issues that happen with UAV mod, then it just must be the 7800 itself. The main thing is that it plays all of my 7800 titles, which it does. Any problem 2600 titles can either be played on my old 7800 or Retron 77. 

I will have to see if my other test 7800 is one that I've disabled the extra timing circuit on. If I have I will see about testing these additional games on it. I don't think I have Kung Fu for the 2600 but I do have dark chambers and double dragon. Though again, the 7800 versions of those games are far better playing experiences compared to the 2600 versions.

 

 

 

 

 

[envytomdead2]

3 hours ago, -^CrossBow^- said:

Though again, the 7800 versions of those games are far better playing experiences compared to the 2600 versions.

For the most part I agree, I have both the 2600 and 7800 for both. I do actually like 2600 Double Dragon quite a bit (I know I'm sick). However I prefer to play it on hardware with a proline (I know I'm sick). 

 

 

[+-^CrossBow^-]

36 minutes ago, envytomdead2 said:

For the most part I agree, I have both the 2600 and 7800 for both. I do actually like 2600 Double Dragon quite a bit (I know I'm sick). However I prefer to play it on hardware with a proline (I know I'm sick). 

 

 

Actually no you aren't sick...maybe a bit of a masochist but I also preferred playing the 7800 version of double dragon with the pain line controllers. I was able to pull off elbow punches left and right with that controller with ease and essentially skate through the game bitd. Not so much now though as my reflexes aren't nearly as good on the timing and I just can't use the old pro-lines anymore LOL!

 

[envytomdead2]

19 hours ago, -^CrossBow^- said:

I also preferred playing the 7800 version of double dragon with the pain line controllers. I was able to pull off elbow punches left and right with that controller with ease and essentially skate through the game bitd

Prolines get a bad rap but I think the diagonals are great on that joy stick so Double Dragon and Kung Fu Master are sooo much easier with it.

[envytomdead2]

Ok so I tested the rest of my 2600 games and found two more problem carts Gravitar and Battlezone. Battlezone technically works but the screen is a little shaky. Now I am wondering if there was an issue with the mod because of the shaky Battlezone screen. Ultimately 4 games out of 70+ games isn't bad and probably isn't worth sweating. 

[+-^CrossBow^-]

I've never had an issue with Gravitar or Battlezone on my personal UAV modded 7800. I've only seen screen shaking occur when a game is using some odd scanline setup that isn't quite to spec. CRTs handled it fine in the day but newer TVs are way more picky and will exhibit some issues. But then I usually see this more on RF vs composite or s-video through a UAV. If anything, the UAV is cleaning up the signal and making it more in spec. But I've got a freshly done UAV 7800 here on my bench now, I will pull these games out and give them a test as I've disabled the extra timing circuit on this 7800 as well.

 

[envytomdead2]

On 6/10/2020 at 9:12 PM, -^CrossBow^- said:

I've never had an issue with Gravitar or Battlezone on my personal UAV modded 7800. I've only seen screen shaking occur when a game is using some odd scanline setup that isn't quite to spec. CRTs handled it fine in the day but newer TVs are way more picky and will exhibit some issues. But then I usually see this more on RF vs composite or s-video through a UAV. If anything, the UAV is cleaning up the signal and making it more in spec. But I've got a freshly done UAV 7800 here on my bench now, I will pull these games out and give them a test as I've disabled the extra timing circuit on this 7800 as well.

 

I'm curious to see what you find!

[+-^CrossBow^-]

52 minutes ago, envytomdead2 said:

I'm curious to see what you find!

Here are the results...

 

 

[envytomdead2]

Thanks for doing those tests. It must just be something with that 7800 I bought. I probably should have just had my original modded. I guess if I want to play those games its my rf only 7800 on a crt or the retron 77 on a modern tv. 

[envytomdead2]

On 6/12/2020 at 7:34 PM, -^CrossBow^- said:

Here are the results...

 

 

So do you think my issues are related to the 7800 itself or do you think something went wrong with the mod?

 

Dark Chambers - black screen

Kung Fu  Master - black screen

Gravitar - black screen

Double Dragon - starts but keeps resetting once you try to start the game.

Battlezone - shaky screen