Macintosh Color Classic: Screen goes purple to white

[LarBob]

I recently got this Color Classic and it has just started exhibiting this issue today. The screen will go from its normal color to purple (and flicker a bunch sometimes) and then back repeatedly during use. I recorded a video so you can see what I mean. I'm guessing it might have something to do with caps but I honestly have no idea. I would think it's almost like it's changing adjustments but then it flickers a lot too so I don't think that's it.

Here is a video: https://youtu.be/atxJzhz73ME

 

[olePigeon]

Might be a loose solder joint somewhere on the analog board, but I couldn't tell you which part.  Whatever makes the green color might be loose.  Could be a simple fix.

Paging Tech Knight.

 

[techknight]

its the adjustment pots. they are known for this. 

 

[LarBob]

its the adjustment pots. they are known for this. 

So... what should I do? thanks

 

[techknight]

clean and adjust the pots? 

Mark their original positions, grab can of DeOxit to spray at the Pots, and sweep them back and forth until they are clean. 

 

[LarBob]

clean and adjust the pots? 

Mark their original positions, grab can of DeOxit to spray at the Pots, and sweep them back and forth until they are clean. 

Okay, I figured, lol. 

 

[Danamania]

If it's not the pots, there's another spot on the analog board that can give those symptoms - mine had the same flickering purple issue. A couple of dry solder joints underneath the highlighted part marked below - and especially bad on the green, which was dropping out (leaving R+B = Purple)

 

[Bolle]

Mine had that problem as well. Cleaning the pots, checking and redoing most of the solder joints on analog and neck board did not fully solve it.

It is also possible that there is bad contact on the harness connector of either the analog or logicboard.

Also make sure the grounding tab spacer spring thingies under the logicboard are actually touching the metal cage.

My cage was slightly bent and the flickering colors seem to have been gone for me since I fixed that.