AppleColor monitor output 'squashed'

[cjtmacclassic]

I recently traded for a IIGS+AppleColor display in unknown condition. The IIGS seems fine, but the monitor is doing this.



I've searched but haven't seen this specific failure mode elsewhere though I imagine these suffer from the same electrolytic fatalities as the machines themselves. What should I try first?

 

[Dog Cow]

electrolytic fatalities .... What should I try first?

I think you just said the answer.

Do you have the schematic for this monitor? 

 

[CharlesT]

I just recently fixed one of these, different symptoms than yours. I replaced all the electrolytics on both the main board and neck board. Did not fix the problem. Problem turned out to be bad solder joints on the flyback. Redid all those and it was mostly working. The other problem turned out to be dirty contacts on the adjustment pots. Gave those some vigorous back and forth action and it came right in. Looks great with the new caps as well. The main board on that monitor is prone to solder joint issues.

 

[techknight]

the only solder joint on the flybcak that would cause THIS symptom is the B+ feed to the vertical output IC. thats it. 

The fact that there is SOME vertical suggests the caps are bad in that circuit. If left like this for too long, it will fry the IC and youll have to locate one of those as well.