800XL: Any ideas on how to fix a color flickering pot?

[seastalker]

I have an 800XL board where the screen was purple, so I adjusted the potentiometer to color correct as usual. Unfortunately it doesn't stay and the color starts to flicker. I've only assumed it is the potentiometer thus far. Maybe an IC? If I can't fix it, would some bypass like Bryan's UAV be possible?

[Osgeld]

Contact cleaner

[Mclaneinc]

The most obvious is to desolder the old one and replace it but I don't know if those little mini preset pots are still on sale these days, we (Maplin) sold then in certain types back then but that's a LONG time ago..

 

Bypasses could get ugly tho..

 

Switch cleaner might help, depends if its dirt on the track or the track is eroded..

Edited September 21, 2018 by Mclaneinc

[R0ger]

Since the pot is typically moved like 3 times over the life of the Atari, I would bet on the dirt. Contact cleaner should work.

[manterola]

And UAV wont bypass the color adj pot.I also have color problems in my 600XL, I thought it was the pot or a capacitor. At the end it was a bad connection of the Phi1 signal that goes to the color adj circuit due to a broken socket.

I changed the Sally socket and the color went back to normal. Check that too.

[seastalker]

So many great responses, thank you! Contact cleaner seems to have helped a little so I may give it a few sprays and put some compressed air on it for the dirt.

[+MrFish]

Try this: Flickering Color Pot Fix

[_The Doctor__]

tuner/switch cleaner spray just before dry work it... spray

 

If spray does not fix it, pinching the the tabs on the potentiometer may help, Take a flat round tool like a punch and support the bottom half of the pot through the access hole in the case/pcb and then a decent flat head screwdriver and bend on the tabs on either side of the adjustmen hole... If you have a plastic one pushing the same idea pushing around the plastic hole can help just don't slip or destroy the plastic..

 

after that retouching solder joints and cleaning reseating stuff may help,

 

if still not cured replace the pot..

 

after that it's check chips time..

 

Before all that...

 

make sure an LCA monitor cord has not gone flakey! and their corresponding jack haven't gotten borked over time.. (if seen this firsthand and had to re seat input board and or solder connectors in televisons (olevia brands etc..)

 

do not forget if using an LCA monitor that has a slider switch that the slider switch on the monitor may need cleaning etc.

Edited September 21, 2018 by _The Doctor__

[seastalker]

Ok- all is looking good!!! I haven't tried it for months yet, but it looks like the contact cleaner and pinching up a bit did the trick. I hope others with this issue find this How To. Thanks again everyone!!!