Longhorn 7800 mod help

[AtariAwesomeness!]

Hey all. Weird issue after doing mod. 7800 games only have a jumpy vertical sync like issue. Turning on/off or removing replacing Cart solves issue. Checked all my soldering and it seems fine. Even replaced cart port and still has issue. Tested power supply on other system works fine. I would appreciate anyone's help and suggestions. Thanks in advance

[phoenixdownita]

It may be your TV, try another set.

Are you connecting via SVideo or composite?

My LCD is fine for 7800 mod via composite but loses sync over SVideo every 5 secs or so.

[AtariAwesomeness!]

It may be your TV, try another set.

Are you connecting via SVideo or composite?

My LCD is fine for 7800 mod via composite but loses sync over SVideo every 5 secs or so.

Thanks for reply. I didn't think about tv. Was hooked up composite via a 55 inch plasma. I tried it on two other non led/LCD tvs and no issues. Apparently it doesn't like my plasma. Thanks again

[+groundtrooper]

I had a problem with my Longhorn mod on S-Video on my Pioneer Plasma.

I sent it to a guy to see what the problem was. He tried it on a non plasma and it had the same issue. He is still working on it. So not sure what is wrong with mine. It has an issue with clock cycles and one other thing.

Stuff that he had never seen happen before.

[phoenixdownita]

So that we close the circle, the 7800 composite is a tad out of std. So the mods tap into the same signals to bring out SVideo or composite or both.

Some TVs allow SVideo to have less digital conditioning (mine is one of those) as compared to composite, and that's when a tad out of std beats you.

Some other TVs also do not like much out of std signals on composite but that's a little rarer afaik, but you seem to have one of those.

 

I can tell you my TV with a 7800 over composite looks like crap but stays in sync, over SVideo it looks gorgeous but ....3 secs at a time as it loses sync in leaps and bounds.

At time I resort to cheap SVideo to HDMI converters and those seems to be fine with the 7800 modded signals, so you may consider that too, as always if you have a chance test it with your gear to make sure the complete chain is working as you expect.

Finally no two 7800 are exactly alike (Atari quality control at its finest) so a different one with the same mod may just work fine.

 

One final caveat for modern TVs and 7800 (LCD and Plasma, CRTs seems to be better instead) you need to compensate the tint control towards more reddish if not then games like Joust and Commando looks way too greenish ... because the way the 7800 generates colors is again a tad weird.

[AtariAwesomeness!]

Thanks to everyone who responded and helped. I truly appreciate it?