Atari 5200 IC function question

[omnedon]

I need to know what IC controls controller input on the Atari 5200 (4 port). I'm not great with schematics. The schematics can be found here: http://www.atariage.com/5200/archive...0_IO_High.html

I just successfully installed the 5200 A/V mod kit from 8bit domain. However, I must have somehow blown the controller input IC, as all it will do now, on all 4 ports, is down and to the left. (this is with known perfectly restored 5200 controllers).

I have a spare 'parts' 2 port 5200 that doesn't output video. I can do an IC swap easy, as some are socketed, but I suspect it's one of the soldered IC's I'm after. I want to know which IC I'm after before I go heating the iron...

ummm... any help?

[omnedon]

Looks like I bent a leg on on the GTIA.



...nothing to see here, folks, move along. These are not the droids we are looking for.

[FABombjoy]

Did you get the 'corrected' version of the mod? I installed this mod for someone after being unable to get the 5200 FAQ's version to look right. The 8bitdomain mod looked pretty good to me, but the 5200 seems to have some persistant vertical lines in the picture regardless of who's mod you do. Any observations on that?

I ended up figuring how to get the 5200 FAQ mod to look good and the picture is pretty comperable. In fact, looking at the chip & looking at the FAQ schem, the only difference seems to be the addition of a CD4050 (and probably some duplicate electronics to get the chroma tidy).

[omnedon]

I'm really happy with it. I had to adjust that pot near the power switch (not the one that controls controller response). At first the colour was washed out and 'off'. I used Pac Man as my reference for colour, as it's the one I 'know' what it's colours should be.

No vertical lines at all. Very clean, and Very sharp. Clearer sound. That said, I am using the composite out, as my gameroom TV lacks Svideo in. For all I know, there could be luma/chroma issues I'm unaware of.

Can't ditch the switchbox yet though. Gotta do the PS mod now. I've got a Genny one in mind to donate an AC socket to the cause. I just need to go odds and ends shopping. I get kind of intimidated in those electronics shops (not Ratshack, but the 'REAL' ones). I know just enough to get myself into trouble. I have to go in with a laundry list ready. I want to snag the stuff I'm gonna need to do the 2600 A/V mod while I'm shopping for various odds and ends.

[FABombjoy]

I want to snag the stuff I'm gonna need to do the 2600 A/V mod while I'm shopping for various odds and ends.

I've done the CD4050, and it's sharp. I've only used s-video with it, tho. Composite doesn't look quite as hot (color ghosting artifacts).

Pick up a pair of 1000uF electrolytic caps, 10V or higher. On several 2600s that I've modded, you can get a set of faint vertical lines running through the picture. Adding the 2 caps in parallel to wherever you tap the board for power should get rid of them. It's worked on every one that I've done so far. These lines weren't very visible on my main TV, but on my bench monitor (Commodore 1701) they stuck out pretty badly.

Be thankful you have a real electronics shop to frequent! I'm all mail order myself.

[omnedon]

Thanks for the tip!

Now that I've spent some time with my AV mod, I guess there ae some faint vertical lines (in composite vid). Very faint, consistently spaced across the screen of my (10 year old) 27" Trinitron. You really have to nitpick to see 'em, but they are there.

Still, the composite is a big improvement over the RF. RF still functions on my unit, and I did a back and forth comparison, and the most striking difference is in the black backgrounds - Just Black, no interference, mild RF snow, or anything. Just Black.