800XL colors went bad during SuperVideo 2.1 upgrade

[redman]

Hello All,

 

I've done the Supervideo 2.1 upgrade about 5 times now on 800XL's and I've always had great results.

 

http://www.wolfpup.net/atarimods/supervid.html

 

This time I finished the Version 2.0 part and everything looked good. I should have stopped at that point. After I finished the 2.1 part, all the colors were messed up. They look like pastels. The 2.1 part is only 4 easy steps so I removed them. The colors stayed the same. I've checked for shorts, removed the 1K resistor from C55, and desoldered and resoldered all the joints. I attached a zip file with pictures from Pole Position taken from a Sony Trinitron 27 inch crt. The picture still looks sharp but the colors don't. I tryed adjusting the color pot but that doesn't help - colors change but not the right way. I hope someone has an idea of what could have gone wrong. The pictures didn't come out too good but you can see the color mismatches.

 

Step by step for 2.1:

 

1 - I installed a new 2.2 ohm to replace the inductor L5. Voltages check out.

 

2 - First I replaced C50 with a 220 mfd. Removed it and replaced with a 100 mfd just to see if it was the cause. No change.

 

3 - Replaced R52 with a 2700 ohm resistor. Removed and put back a 2000 ohm. No change.

 

4 - Installed a 1K resistor where instructed to. Removed it for testing. No change.

 

I must have screwed something up but I don't know where to look. Thanks for listening. I hope someone has an idea of how to fix this.

 

redman

BadColors.zip

[Rybags]

To me it looks a bit like the colour is overdriven and drowning out the luma.

 

I had problems with an 800XL video mod as well (probably that one). My fix was to reconnect a diode.

For you I'd suggest try backing off one at a time anything that boosts colour. Of course with this stuff it's much easier if you have the components to be able to go back to what it was each way.

[redman]

Thanks Rybags,

 

I'll try upping the resistance of the 2.2 ohm and see what happens. It should be one the last 4 steps of the upgrade because the video looked fantastic after the end of the 2.0 process.

 

redman

[fujidude]

To me it looks like there is little saturation to the colors.