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Atari 7800 SVideo UAV Mod

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11 minutes ago, -^CrossBow^- said:

Forgot to mention that what I use to mount the UAV boards is section of 3M velcro.

That's a great idea! I'll give that a go when all the other pieces arrive, thanks Jesse!

 

- James

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7800 Mod Finishing Touches Parts Update:

 

Arrived:

- Heat Gun

- Heat Shrink Tubing

- Extra Strength Adhesive Velcro

 

Ordered:

- Pokey Chip from Best Electronics

- 2x 6ft Joystick Extenders (for AtariVox)

- Desoldering Braid

- Scotch Super 33+ Electrical Tape

- IC Puller Tool

 

Once it all arrives I'll post an update on all the final touches to the 7800 mod! I think the slowest one will be the Pokey Chip but hopefully I can do another Atari 7800 stream before the Nomination shows start on the 15th!

 

- James

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BIG UPDATE, Best Electronics have shipped a Pokey chip to me!

 

The email communication was a little strange, but went unexpectedly smooth, especially after all the horror stories I've read. Hooray!

 

I have some 7800 games scheduled for next Tuesday's ZPH show but those may have to be postponed if the Pokey Chip doesn't get here in time. I want to make sure people can hear all the amazing work the developers put into these great 7800 homebrews.

 

- James

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12 minutes ago, ZeroPage Homebrew said:

The email communication was a little strange, but went unexpectedly smooth

They could put that on a T-shirt.

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Part Six: Mod Clean Up (The End!)

 

Based on the recommendations of @-^CrossBow^- and @Nathan Strum I bought a bunch of equipment to clean up the work I'd accomplished so far! Most of the pieces I had ordered had come in so I thought I'd take the system apart and go at it again, plus I want to use the system on this coming Tuesday's show for some more 7800 gaming!

 

 

Heat Shrink the Audio Connector:

 

The first step was to get some heat shrink tubing around the exposed wiring on the dual mono audio connectors. I desoldered the blue and red wire from the capacitor, slipped an appropriately sized red tubing over it and resoldered it. I then applied some heat from my new heat gun to it. It didn't quite generate enough heat on the lowest setting but on temperature setting two it almost instantly shrunk it! The heat shrink tubing worked great and covered all the exposed wiring nicely without having to worry about it touching the RF shield.

 

PXL_20201231_075848254.thumb.jpg.0e37141aa8cbb218a3a22db38abe10d1.jpgPXL_20210110_063738877.thumb.jpg.c010cfcd0169842ed3c595cfd75b230a.jpgPXL_20210110_064514461.thumb.jpg.b70fc4c65142e83eb27b03aaf6de7ae0.jpg

 

Velcro UAV to 7800 Board:

 

The UAV board has been swinging wildly around inside the case making me nervous so I bought some really strong velcro to attach it to the 7800 board, specifically to two chips that Crossbow says don't get hot while the system is in operation. I had tried double sided sticky tape but it just wasn't strong enough to keep it all together. The 3M Velcro I bought has some serious adhesive to it and I had already used it on two other items after I bought it as tests before applying to the 7800. I measured and cut out the two pieces, one for the UAV chip and the other to put across the two chips on the board and then stuck them on. It worked excellent and the velcro holds the UAV extremely tight in place. I also have tons of velcro left over for other projects that I have coming up.

 

PXL_20210110_064630369.thumb.jpg.3686bd244d3321d41ef67619db3f5d8b.jpgPXL_20210110_065207907.thumb.jpg.4aef25c99c8d862e110332fa4c80309b.jpgPXL_20210110_070021747.thumb.jpg.b3758ef8900f1c18d970acf3b6b328b1.jpg

 

Protect the Wires:

 

The third part of the cleanup comes with the opening in the RF shield where some wires were coming out. I ordered some heavy duty 3M electrical tape but it's back ordered for a few weeks. I looked around the house and found some terrible electrical tape that should work fine in the mean time and will be better than the masking tape (!) that I put in place. I first broke off the piece of metal that I had just bent back by moving it back and forth until it came off from fatigue. I then wrapped the horrible electrical tape around the wires and all around the metal opening to reduce the chance of rubbing and wearing away the plastic around the wires. The horrible electrical tape worked... okay. It will be replaced as soon as the good stuff comes in.

 

PXL_20210110_071752932.thumb.jpg.784adf37c34a5aea8a4367c620a65592.jpgPXL_20210110_072640520.thumb.jpg.05b709b10d7c61a1cafcb4f3bee1244c.jpgPXL_20210110_072659562.thumb.jpg.37f8c37b0a795acfd1759b59108cb066.jpg

 

Future Troubleshooting 7800 Chips

 

I saw a bunch of people on the Concerto Cart page posting their chip numbers for troubleshooting issues they had with their system so I also took a bunch of photos of the chips on the board.

 

PXL_20210110_072715340.thumb.jpg.047d9c4f4c17562d028c8e43f9370bf2.jpgPXL_20210110_072718889.thumb.jpg.9bd4f2918a8cf3c60d7e967198e81d7f.jpgPXL_20210110_072738354.thumb.jpg.b4084ab975fb408f51645685cf23533c.jpgPXL_20210110_072728807.thumb.jpg.95f956d09e3235ed2ea2f1b145549b3b.jpgPXL_20210110_072751137.thumb.jpg.24876dba42884bc85a959b24df0a84c0.jpgPXL_20210110_072805316.thumb.jpg.1cfa0710f31f7311ead2856dca550262.jpgPXL_20210110_072815275.thumb.jpg.dddb041d1f5fbf685fc9c323c1fec563.jpgPXL_20210110_072834662.thumb.jpg.6b7ec082979c5573d27ecf3e6ff4686f.jpg

 

 

What's Left

 

Not much is left to do inside the 7800 really! Once the proper electrical tape comes in I'll be replacing the white terrible stuff I've used. Then once the Pokey Chip comes in from Best Electronics I'll be attempting to install that into the Concerto Cart. It looks really simple to do and somebody recently was wondering which direction to install it so now there's very clear instructions on how to put it in. So this is probably the last entry in this thread until something terrible happens to the mod (hopefully not!).

 

A huge thank you again goes to @-^CrossBow^- and @Nathan Strum for their solid advice throughout this very successful journey and I'm actually now looking forward to doing other projects I have on the rosters such as the RGB Intellivision Mod I have waiting.

 

- James

 

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On the output wires...just take them out of the green terminal block, and use some shrink tubing around the bundle in that section. It should be thick enough to protect the wiring without issue. I've done that sometimes, but on the entire small corner section of the RF shield, I actually remove that whole segment off cleanly and then apply a little kapton tape around the edge where the break was just to make it that much more smooth. But yeah I'd say you would be fine just adding some shrink about the bundle.

 

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1 hour ago, -^CrossBow^- said:

On the output wires...just take them out of the green terminal block, and use some shrink tubing around the bundle in that section. It should be thick enough to protect the wiring without issue. I've done that sometimes, but on the entire small corner section of the RF shield, I actually remove that whole segment off cleanly and then apply a little kapton tape around the edge where the break was just to make it that much more smooth. But yeah I'd say you would be fine just adding some shrink about the bundle.

 

Great idea! I never even thought about putting some shrink tubing around that bundle to protect it. Way easier than trying to tightly wrap electrical tape around them.

 

I didn't know what the ramifications of removing too much of the RF shield would be but some people never put it back on so it should be fine. I admit that snipping off that whole segment would make taping it up a LOT easier. I've never heard of Kapton Tape before but I'll order it as it looks extremely useful for possible future projects as it can withstand high heat. Thanks so much!

 

- James

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Follow Up:

 

I got my Pokey chip yesterday from Best Electronics, showed it on the stream and installed it today!! So very excited to come to the end of this journey!

 

 PXL_20210120_221809943.thumb.jpg.e4102ebb920e964437cfbd86234e34ca.jpgPXL_20210120_221822265.thumb.jpg.2159b911f191be60c41fa5d1ebac9fdd.jpg

 

 

 

I was a bit frightened of installing it in the incorrect orientation but it was actually very straightforward, matching up the notch to the notch! It went in fairly easily and I was extremely careful to make sure all the pins went into the slots. I pushed it as far as I felt safe pushing it in as shown in the pictures below. I then tried to put the top of the cartridge case back on, it wasn't having it so I knew something was wrong...

 

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I then looked up pictures online of correctly seated chips and quickly determined that it needed to go in a LOT further than how I had it. D'oh! I then pushed with quite a bit more force than I was comfortable with and it squeaked into place! BOOM!

 

PXL_20210120_230600917.thumb.jpg.c9c64323f1d3efe79472cd2e309afcce.jpgPXL_20210120_230549744.thumb.jpg.27fe6eeac05114e64ddf3b7c3c4ec343.jpgPXL_20210120_230608279.thumb.jpg.cb2e673d7a98bace6fdc6b40783562b2.jpg

 

I popped it into the 7800 and ran through a number of games for testing. Ballblazer, Froggie, Bentley Bear and Beef Drop all sounded great so I felt secure that it was working. There's some slight audio issues with a couple of recent WIP homebrews but I've reached out to the developers to see if it's just me or there's some known issues.

 

I'll now be ready for the 3rd Annual Atari Homebrew Award 7800 Nominees with real hardware to show off their games on the stream, hooray!

 

- James

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Danger Zone's Pokey tunes (Atari Age jingle, title theme and B side track) don't work on Concerto at the moment as Concerto doesn't support Pokey at the $450 address space on 48kb Rom sizes yet.

 

It's not a limitation of the cart, supporting Pokey at $450 is fine as shown by the 128k scheme (Milly & Molly, Popeye etc.). It just hasn't been added to the firmware yet for 48kb ROMS.

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18 hours ago, Muddyfunster said:

Danger Zone's Pokey tunes (Atari Age jingle, title theme and B side track) don't work on Concerto at the moment as Concerto doesn't support Pokey at the $450 address space on 48kb Rom sizes yet.

 

It's not a limitation of the cart, supporting Pokey at $450 is fine as shown by the 128k scheme (Milly & Molly, Popeye etc.). It just hasn't been added to the firmware yet for 48kb ROMS.

That makes a lot of sense, thanks for letting me know! Danger Zone was one of the games I tested that didn't give me any audio at all. I'm going with the assumption right now that my Pokey is fully working and any weirdness that I'm experiencing is fixable and will be addressed with firmware updates. 🙂

 

- James

Edited by ZeroPage Homebrew
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INSTALL OF ATARI 7800 CHROMA FIX MOD

 

The amazing @-^CrossBow^- sent me his Chroma Fix board for me to try out on my 7800 system to correct some of the edge bleed that occurs in the video output. Here's the board and my 7800 for a size comparison.

 

PXL_20211128_222518943.thumb.jpg.e2e0909858ea2247f33e50fd36b12357.jpg PXL_20211128_222533642.thumb.jpg.6ed07511eee17e6fe0818ab5fee3d786.jpg

 

He's designed the board so it fits nicely on top of the existing UAV mod for a compact install. The empty holes in the UAV line up exactly with the ground and +5V power for the Chroma Fix board. Here's the UAV as it's installed on my 7800 along with two connecting pins soldered into place.

 

PXL_20211128_225811877.thumb.jpg.5b2df2cb315950e73b8105e9b680c288.jpg PXL_20211128_231112113.thumb.jpg.6c2d3203a2f379392c8c06a600804868.jpg

 

PXL_20211128_231015501.thumb.jpg.b641d235962019746857f990ae16449f.jpg

 

The next step is to disconnect the yellow colour input wire from the UAV board and connect it to input on the Chroma Fix board, then you take the output from the Chroma Fix board and feed it into the input of the UAV board.

 

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And really, that's it! It's a super easy install and you can watch the video @-^CrossBow^- posted about the install on his YouTube channel here. It really cleaned up a lot of the bleed on the edges to make for a much clearer picture. The darker colours are still a bit mushy but those aren't used as often.

 

I pushed this install forward ahead of my 5200 power + UAV mod so I can use it for the return show for ZPH tonight for the premiere of three new amazing 7800 games from @mksmith! Below is a look at the output from the 7800 now with the Chroma Fix mod through s-video and the RetroTINK 5X-Pro! Hopefully the improvement will be noticeable in the stream tonight, I find it a lot cleaner (sorry, no 'before' shot to compare with 😞) .

 

- James

 

1554411293_20211128-Atari7800-ChromaFixUpgrade.thumb.png.6a24f9dfafdaa794eebd1ebc3d39405d.png

 

 

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Again the real credit for this particular circuit design goes to @marauder666 and @juansolo. I just designed a PCB with the components on it to help make installing it easier as I really think it should become a staple part of any 7800 UAV installations. I've been adding it myself for the past few months and really think it helps. 

 

It also has to be stressed that the results of this will vary from console to console due to variance.

 

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I wonder why darker colors bleed much more than bright ones. Isn't usually the opposite happening?

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6 minutes ago, -^CrossBow^- said:

Again the real credit for this particular circuit design goes to @marauder666 and @juansolo. I just designed a PCB with the components on it to help make installing it easier as I really think it should become a staple part of any 7800 UAV installations. I've been adding it myself for the past few months and really think it helps. 

 

It also has to be stressed that the results of this will vary from console to console due to variance.

I'm going to be modding a 7800 for John Champeau soon-ish. I may be PM'ing you about one of those boards. :) 

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I also want to mod my 7800. Can someone point me to the required pieces/boards?

 

I know it won't be cheap. I have to get them to Chile!!!

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18 minutes ago, vitoco said:

I also want to mod my 7800. Can someone point me to the required pieces/boards?

 

I know it won't be cheap. I have to get them to Chile!!!

I have talked with @MacRorie with The Brewing Academy a little here and there about possibly providing a few to him to test and see about making them part of the 7800 UAV kits going forward. But using these does require the installer to tweak both the trimmer on the UAV (Previously this didn't do much but it does now especially in composite), along with the actual color trimmer on the 7800 itself to dial in to best preference. But even if none of that was done, leaving the trimmer on the UAV to just under a quarter of the lowest setting and leaving the trimmer on the 7800 as is, is ballpark enough in most cases.

 

The new SMD version on the other hand due to differences in the chips used. Requires the UAV trimmer to be set to the full rightmost position and then backed off a notch or two to get best results.

 

The parts required is nothing more than 2 components. You need a 4050 IC and a 100nf cap. I used the MLCC you see here as I have a lot of those on hand. I've been ordering my 4050s from both Mouser and Console5.

 

James got the last one of the first 5 PCBs I had made up as all the others since, are white colored PCBs to match the UAV better when put together.

 

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31 minutes ago, Nathan Strum said:

I'm going to be modding a 7800 for John Champeau soon-ish. I may be PM'ing you about one of those boards. :) 

Not a problem, just let me know if you would rather have one of the through hole versions like shown here or the newer SMD board? The SMD version is... well it is pretty small I warn you. Because of that, only the GND is a true via on that board and the rest are just small solder pads for +5 and MC-in and MC-out. But, you can still install it ontop of the UAV but it will only cover over about 1/4 of the UAV board in the process. Here is a pic of the SMD version as I installed it on @sramirez2008's 7800 not long ago.

 

 

CFix_v2_UAV_Combo.jpg

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38 minutes ago, -^CrossBow^- said:

one of the through hole versions

Have to admit, that through hole version is pretty cool.👍

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Good to see this working on more 7800s,  it had only been tested on a few NTSC models before Crossbow made the PCB for it.

It was a reinventing of the wheel, the TailChao mod hidden away on the forums had a different logic chip on it to delay the chroma signal, we were unaware of it at the time.

 

I recently tried it on my newly imported 5200 and it doesnt work, the luma/sync needs delaying in that one.  Using this method, it would take 5 4050s to do this, not worth the effort.

Can't do it after the luma and sync signals are combined as the signal is then analogue.  My 5200 looks really good anyway, it was just an experiment.

 

 

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4 hours ago, marauder666 said:

Good to see this working on more 7800s,  it had only been tested on a few NTSC models before Crossbow made the PCB for it.

It was a reinventing of the wheel, the TailChao mod hidden away on the forums had a different logic chip on it to delay the chroma signal, we were unaware of it at the time.

It got a good demo with three new 7800 games on the last ZPH broadcast, the output looked incredibly crisp with the Chroma Fix mod!

 

- James

 

(WATCH AT 1080P60 FOR FULL QUALITY)

 

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