Faint lines on white backgrounds

[Johnnya101]

-Mac SE/30 with recapped analog and logic, original power supply-

I noticed today on my se/30 that when there is a running program with a white background, there are super faint almost like scan lines on the screen. They just roll from bottom to top. Super super faint. There at all brightness levels. That was in a paint program. At desktop or in a white finder window they are not there. Is this yet another power supply issue? Is it showing signs of needing new caps? I can upload a video but it's hard to see them.

Edit: video. You can barely see the almost shimmering effect I guess? Hard to see. If this is an issue I'd like to catch it quick.



View attachment 20190121_080207.mp4

 

[Johnnya101]

It must just be my eyes being used to a perfect modern LCD. I turned the SE/30 on again. Very very VERY faint lines. They are horizontal and go from the bottom up. Very hard to see. You really have to be within a few inches from the screen to see them, from normal viewing distance they are not visible. I'm sure having an original PSU doesn't help, but Id say these are normal for an 80s CRT when being inches away? They don't get worse with reading from a floppy, indicating the PSU is handling a load okay. Don't have another compact to test to see if I see them.

 

[Byrd]

The brightness cutoff is probably too high; crack it open and adjust the CRT pots

 

[Johnnya101]

Ill have to get some plastic adjusting tools. I tried using a skewer but it doesnt want to turn anything. I also need to adjust the size. Ill try and do that at the same time.

Are you sure cut off would cause perfectly horizontal line though? Arent cutoff lines kind of angled? It also doesnt matter on brightness. Again, it might just be my eyes since CRTs looks so different than LCDs, and it is just how the smaller compact CRTs are.