7800 A/V Video Mod - results?

[tremoloman2006]

Have any of you installed the 7800 S-Video mod boards yet created by Longhorn Engineer?

 

If so, how did it work out? I'm hoping to compare results.

 

Regards,

Trem

[mimo]

I replaced an 8shitdomain mod with one of the original Longhorn mods. The LHE mod is so much better and the new version is no doubt better than the original.

I also have Longhorns own PAL 2600 that has a development board fitted. It has issues with some TVs but the ones I have tried on, especially LCD sets the mod is simply unbelievable, no vertical lines, pin sharp pixels.

Well worth the money and time to install.

Looking forward to the PAL version for the 7800 when it is ready, will definitely get one of those, and probably an NTSC one when funds allow to replace the original LHE one that is installed

[tremoloman2006]

I replaced an 8shitdomain mod with one of the original Longhorn mods. The LHE mod is so much better and the new version is no doubt better than the original.

I also have Longhorns own PAL 2600 that has a development board fitted. It has issues with some TVs but the ones I have tried on, especially LCD sets the mod is simply unbelievable, no vertical lines, pin sharp pixels.

Well worth the money and time to install.

Looking forward to the PAL version for the 7800 when it is ready, will definitely get one of those, and probably an NTSC one when funds allow to replace the original LHE one that is installed

 

So are you talking about the 7800 mod or the 2600 mod?

[Ransom]

I installed the LE's 7800 mod a month or so ago.

 

I'm very, very pleased with the S-video output. It looks fantastic both in 7800 and 2600 mode.

 

The composite output is problematic, however, in that there is a delay for some of the data to be processed via that route. So you get shadowing. It's glaringly obvious on titles like Adventure, but not so obvious on titles like Space Invaders or Galaxian. I notice it in 2600 mode. 7800 mode seems pretty good with the games I have.

 

LE is aware of this problem and has said that it is inherent to the chips used.

 

So if you want fantastic S-video output from your 7800, get this mod! If you're only interested in composite...well, it's probably not worth doing, IMO.

[mimo]

sorry for the confusion, maybe I should proof read before hitting the button:roll:

 

NTSC 7800

I replaced an 8shitdomain mod with one of the original Longhorn mods. The LHE mod is so much better and the new version is no doubt better than the original.

 

PAL 2600

 

I also have Longhorns own PAL 2600 that has a development board fitted. It has issues with some TVs but the ones I have tried on, especially LCD sets the mod is simply unbelievable, no vertical lines, pin sharp pixels.

Well worth the money and time to install.

[gdement]

I installed the LE's 7800 mod a month or so ago.

 

I'm very, very pleased with the S-video output. It looks fantastic both in 7800 and 2600 mode.

 

The composite output is problematic, however, in that there is a delay for some of the data to be processed via that route. So you get shadowing. It's glaringly obvious on titles like Adventure, but not so obvious on titles like Space Invaders or Galaxian. I notice it in 2600 mode. 7800 mode seems pretty good with the games I have.

 

LE is aware of this problem and has said that it is inherent to the chips used.

 

So if you want fantastic S-video output from your 7800, get this mod! If you're only interested in composite...well, it's probably not worth doing, IMO.

 

You could just use an SVideo -> composite adapter, so you're getting the signal from the svideo output.

In fact I'd do it that way anyhow, rather than having to install 2 separate output ports.

[Longhorn Engineer]

Yes the composite isn't as great as I hoped it would be. On CRT TV's this issues seems to be somewhat diminished. The main reason this happens is the extra chip on the 7800 mod delays the luma just a bit more. I have been trying to figure a way around it but I would have to move to all SMD parts (even smaller SMD then I am already using) to get the speeds that would take care of the problem.

 

At least the S-video is performing well.

 

Thanks for the compliments. I wish I could do something about the composite but without redesigning the entire thing there isn't much. Next time I get to redoing the 7800/2600 mods will be for HDMI

[Ransom]

You could just use an SVideo -> composite adapter, so you're getting the signal from the svideo output.

 

That's a good point. I may do that since the monitor I have it set up with can only do either S-video or composite (you can't have both hooked up at the same time), and the other systems that use that monitor only do composite. Thanks for the idea!

[Underball]

You could just use an SVideo -> composite adapter, so you're getting the signal from the svideo output.

 

That's a good point. I may do that since the monitor I have it set up with can only do either S-video or composite (you can't have both hooked up at the same time), and the other systems that use that monitor only do composite. Thanks for the idea!

If you're only looking for composite video, the "easier composite video mod" thread gives great instructions on how to build one that is excellent. I'll try to post pics tonight or this weekend. There's no chips involved, it's just a simple signal amplifier, so there's no chroma or luma delaying going on.

[Ransom]

If you're only looking for composite video, the "easier composite video mod" thread gives great instructions on how to build one that is excellent. I'll try to post pics tonight or this weekend. There's no chips involved, it's just a simple signal amplifier, so there's no chroma or luma delaying going on.

 

Would that affect the Longhorn Engineering mod I already have in there?

[Underball]

If you're only looking for composite video, the "easier composite video mod" thread gives great instructions on how to build one that is excellent. I'll try to post pics tonight or this weekend. There's no chips involved, it's just a simple signal amplifier, so there's no chroma or luma delaying going on.

 

Would that affect the Longhorn Engineering mod I already have in there?

It might.

 

I'd be curious to see a side by side of LE's composite signal vs. that one. I know it's not as clean as his S-Video signal, but it might be a little better than the composite out from his mod.

[Ransom]

If you're only looking for composite video, the "easier composite video mod" thread gives great instructions on how to build one that is excellent. I'll try to post pics tonight or this weekend. There's no chips involved, it's just a simple signal amplifier, so there's no chroma or luma delaying going on.

 

Would that affect the Longhorn Engineering mod I already have in there?

It might.

 

I'd be curious to see a side by side of LE's composite signal vs. that one. I know it's not as clean as his S-Video signal, but it might be a little better than the composite out from his mod.

 

Hmm. I should probably just go from S-video to composite then, to avoid any problems. Next time, though!

[tremoloman2006]

Unfortunately my results haven't been so good. After the pre-built 7800 board was installed, the picture result is crystal clear but suffers from low color, severe color bleed, and some weird flickering in the background of the screen where no color is present. I had the same problem with all my 2600 mod boards until the last revision was applied to the initial design.

 

I sent Longhorn Engineer a few private messages over the past two weeks asking if he could assist me in troubleshooting. As of this message, I have not gotten any correspondence. His lack of support has been disappointing to say the least.

 

This install was done on a brand new 7800 by a professional who has handled several 2600 systems for me over the past year. My 7800 worked perfectly before the mod was performed.

 

Does anyone have any advice on how I can correct these issues?

[+Mitch]

Unfortunately my results haven't been so good. After the pre-built 7800 board was installed, the picture result is crystal clear but suffers from low color, severe color bleed, and some weird flickering in the background of the screen where no color is present. I had the same problem with all my 2600 mod boards until the last revision was applied to the initial design.

 

I sent Longhorn Engineer a few private messages over the past two weeks asking if he could assist me in troubleshooting. As of this message, I have not gotten any correspondence. His lack of support has been disappointing to say the least.

 

This install was done on a brand new 7800 by a professional who has handled several 2600 systems for me over the past year. My 7800 worked perfectly before the mod was performed.

 

Does anyone have any advice on how I can correct these issues?

 

Is this with s-video or composite hookups?

 

Mitch

[tremoloman2006]

Is this with s-video or composite hookups?

 

Mitch

 

Sorry... it's S-video.

 

I've tried this one 2 different TVs and get the same result. Composite is even worse.

[Underball]

for a frame of reference, here's a few crappy iPhone pics of my 7800 with the "easier composite video mod" on my new Samsung LCD HDTV.

[Longhorn Engineer]

Sorry Trem I am still trying to catch up on all my emails and PMs from when I was injured. The 7800 mod isn't as clean as the 2600 mod in that there is induced lag due to the OR chip to separate the Luma lines. So its Luma lag. It does look much more serious in your condition however.

 

The problem with the easy composite mod is that it used the 7800's OR chip that is inside which is even slower then the one I used. I have been trying to come up with a solution to the problem but it really is that there is nothing that can be "fixed".

 

Have you tried different cables? If you get the same results on two TVs I would suspect the cable to be an issue. Remember these are analog signals (Finicky Atari signals at that) and need proper shielding.

 

Trem if you want to you can ship your Atari to me so I can see if there is a problem with it. I do want to figure out what is wrong here.

 

Parker

[tremoloman2006]

Sorry Trem I am still trying to catch up on all my emails and PMs from when I was injured. The 7800 mod isn't as clean as the 2600 mod in that there is induced lag due to the OR chip to separate the Luma lines. So its Luma lag. It does look much more serious in your condition however.

 

The problem with the easy composite mod is that it used the 7800's OR chip that is inside which is even slower then the one I used. I have been trying to come up with a solution to the problem but it really is that there is nothing that can be "fixed".

 

Have you tried different cables? If you get the same results on two TVs I would suspect the cable to be an issue. Remember these are analog signals (Finicky Atari signals at that) and need proper shielding.

 

Trem if you want to you can ship your Atari to me so I can see if there is a problem with it. I do want to figure out what is wrong here.

 

Parker

 

Parker,

 

Thank you for your reply.

 

I have tried different S-Video cables as well as different TVs. I'm using high-quality gold plated cabling and also had gold-plated S-video and audio jacks installed on the 7800. I'll take some pictures of the 7800 mod board for you as requested later today and ship it to you if necessary. Hopefully its something simple.

 

Regards,

Trem

[tremoloman2006]

for a frame of reference, here's a few crappy iPhone pics of my 7800 with the "easier composite video mod" on my new Samsung LCD HDTV.

 

 

Thanks for the pictures... they look pretty damn good from here!

[Underball]

for a frame of reference, here's a few crappy iPhone pics of my 7800 with the "easier composite video mod" on my new Samsung LCD HDTV.

 

 

Thanks for the pictures... they look pretty damn good from here!

I took the time this weekend to really clean it up. I used a printed circuit board to connect everything, instead of just soldering the parts together. (I realized in doing this the first time, I had dripped some excess solder onto the 7800 mobo which was causing minor interference.)

 

In addition to the "final" instructions in post 14 of the Easier Composite video mod thread, I also made the addition of swapping out R11 for a 100k pot (Luma1), and R16(7800 Chroma) and R17(2600 Chroma) for 10k pots both. This cleaned up 98% of the ghosting/shadowing/color bleeding. I swapped out the 75 ohm resistor from the ground to the video out cable for just a straight 47 ohm. I also used gold plated RCA jacks, all new 22 gauge project wire, and a nice, clean new spool of .63 rosin solder.

 

I'm really happy with the results. As I don't have the option of S-Video on either of my two new HDTVs (a 2009 Samsung 32" LCD, and a 2009 Mitsubishi 65" DLP) I wanted to perfect the Composite Video out. I think it looks pretty great. there's a tiny bit of dark blue ghosting around the maze in Pac-Man, but only noticeable if you're right up on the TV, like less than 3 feet from it. Other than that it's tight as a drum. Even the 320 mode text in Pole Position II looks really good with minimal, if any, shadowing. I'll post better pics with my real camera (Nikon) later.

 

 

Also, here's an updated version of the Instructions:

 

*UPDATE*

7-8-2008; I have updated the instructions to include the POKEY audio fix and a resistor change that will bring down the brightness so light collored objects are not over-driven. Here is the info for the mod:

 

Parts List:

------------------------------------

2.2k 1/4 watt resistor

3.3k 1/4 watt resistor

47 ohm 1/4 watt resistor

47K to 68K 1/4 watt resistor

100k potentiometer

2 10k potentiometers

2n2222 or 2n3904 transistor

2 RCA jacks

hook up wire

-------------------------------------

 

Procedure:

 

1. Open up the 7800 and remove the metal shield.

2. Locate R3 and R5 and remove them. this is a good time to drill two holes and install the RCA Jacks. I installed mine facing down on the edge of the case.

3. Locate R11 and replace it with a 100k potentiometer. Also - locate R16 (7800 Chroma) and R17 (2600 chroma) and replace them each with 10k potentiometers. I found that turning R16's pot all the way to the left, and R17's pot all the way to the right produced an absolutely pristine picture, once R11 was adjusted to a nice contrast between saturation and color.

4. Cut the pins that connect the Video modulator to the board. (don't do this if you ever think you will use the RF out in the future)

5. Build the circuit in the schematic. (substitute a 47 ohn resistor for the 75 ohm shown if you want) I used a printed circuit board and connected a wire from the transistor's collector to the 5V connection on the expansion bus connector. The connection is the third point from the bottom on the right side. I made my ground connection by soldering the resistors to the edge of the board. I then ran a small wire to the video connection where the RF unit used to connect to the motherboard. Video signal is the 2nd pin from the RF unit down. Finally I ran a yellow wire to the RCA jack.

 

6. for the Audio, all I had to do was run a wire from the top of C10 to the audio jack. I actually made the connection by running a wire from C10 to where the audio jack connects to the resistor I added for he audio.

 

Here is a picture of the wire:

 

Here is a close up of the connection at C10:

 

Here is a close up of where the POKEY audio meets the audio out:

 

7. Run a wire from the top of C10 to the audio jack. This is the POKEY audio. I actually made the connection by running a wire from C10 to where the audio jack connects to the resistor I added for the audio output.

8. I connected the ground wires to the RCA jacks and connected the other end to the ground trace on the edge of the board.

9. Put the 7800 back together and enjoy the clean video and audio!

 

Here are some pics that will help explain:

 

Here is the upgrade. You can also see where I cut the RF modulator pins:

 

Here is a close up of the resistors to be removed:

 

Here is a closeup of where to find R11:

 

Here is the Amplifier Schematic:

 

Here is the amplifier installed in the 7800. The only solder points to the board are the 5V, ground, and the video in signal:

 

Here is the audio connection:

 

Here is where to make the POKEY connections:

 

Here is a close up of the C10 connection:

 

Here is a close up of the connection point to the RCA jack:

 

Here is a closeup of the RCA connectors:

 

Here is another view of the RCA connectors:

 

 

Enjoy!

[Underball]

a few more not so great iPhone pics.

[PacManPlus]

Hi:

 

I hate to do this, but I am not getting results through PMs.

 

I know he was recovering from a dog bite last month, but I sent the mod back in the end of January (with a display issue) and I still have no result yet. He did send me a PM the beginning of this month saying he would look at that week, and I've heard nothing. I also sent him two PMs, and still nothing. I know he's been on so I don't understand why he's not answering me.

 

At this point, I'm just asking for a refund. I did not have this much trouble with 8-Bit and their mod.

 

Bob

[the.golden.ax]

He is probably just in a big hurry to get ready for MGC. He should communicate though. I'm a well intentioned scatter brain myself with too many projects. (not that LHE is scatter brained, I think in his case, spread too thin?)

 

AX

[PacManPlus]

He actually just sent a PM today and said that he was still looking at it. He said he might be having PCB trace issues.

 

Thanks,

Bob

[PacManPlus]

Ok - now I'm very aggravated.

 

I finally got the mod kit back on Monday after 2 months (half of that with no responses), and it does the same thing. I tried it on two TVs, and finally replaced his mod back with the 8-bit domain mod, and the 7800 works fine.

 

I send him another PM asking for a refund and he hasn't answered. When I look at the "participants" in the PM, it shows that he "has left the conversation". :x

 

DO NOT DO BUSINESS WITH LONGHORN ENGINEER! If your mod works, you are lucky, but if something doesn't work, you are out of luck and he already has your money.

 

I know I'm not the only person this happened to.

 

 

I didn't have this trouble with 8bitdomain, and I've bought a few things from them.

 

Bob