AV Mod issue

[Phil]

For fun, I decided to convert my 4-switch 2600 to A/V output, using Ben Heckendorn's Mod. With the Chroma and Luma tied together, I get a pretty good picture on a composite monitor/TV. It's not quite as nice as I'd like it to be, but it's still a major improvement over the RF connection. To see if it'd look nicer, I took it partway apart, so I could connect the separate chroma and luma signals to the chroma/luma inputs of a Commodore model 1702 monitor. It looked nice for an instant, but after that, I couldn't get anything but a black and white rolling mess on the screen. I'm wondering if it's a problem with my monitor, as disconnecting the chroma from the monitor doesn't seem to change the mess that's displayed, or if it's the A/V mod. Any suggestions?

 

--Phil[/url]

[darkman]

That is interesting... I have performed this mod three times now, however I never bothered to out put the Croma and Luma seperatly. I do have one of those nice C= monitors, however... I just simply wanted easy connection to the front of my TV. I was just amazed to get Composite Video in the first place.

 

My question for you is, if you combine the Croma/Luma with say, a RCA Y addapter... and hook it up to the the Composite input again, does the picture look good again?

 

Also... have you adjusted the Patromitors? (sp?) I found that they need a little fine tuning, otherwise you can loose your picture.

 

I learned that there are serveral ways to do this AV mod. Most are very simular. One difference I noticed, is that some of the guides tell you to go in different places on the MB to get your seperate signals, and then tap into the Stella Chip for the rest. You can, get everything you need directly from Stella, without any need to poke around other places on the MB. I would suggest checking all your connections (resolder if needed) and maybe solder everything directly to Stella.

 

What I found works best for me, is solder all Video related wires to Stella, and snag the audio sigal from on the MB. I was having problems with the Audio...

 

Anyway... hope some of my ramblings helps.

 

-darkman

[Phil]

Yea, I can recombine the chroma and luma and get a composite signal again.

 

The luma signal is coming from 4 wires soldered directly to the Stella socket. Chroma and audio are coming from the junctions of resistors/capacitors mentioned on the page linked above.

 

One thing I've seen, is that to properly combine chroma and luma into composite you need to use a capacitor between the two lines. For what reason, I'm not sure, but I may give that a shot. I'll link to the page I saw that on if I can find it again.

 

--Phil