Flickering screen

[zoo]

I have this flickering, it seems to be less pronounced once the computer has warmed up. Searched the dead mac scrolls but there was bo exact match, what is your opinion?

 

[zoo]

Different machine, any thoughts on that?

 

[croissantking]

I have this flickering, it seems to be less pronounced once the computer has warmed up. Searched the dead mac scrolls but there was bo exact match, what is your opinion?

Have you recapped the analog board yet?

Different machine, any thoughts on that?

I’ve seen that when I had a poor flyback anode connection to the CRT.

 

[zoo]

Have you recapped the analog board yet?


I’ve seen that when I had a poor flyback anode connection to the CRT.

Not yet, I struggling to get my hands on the BU406D transistor and the 3.9t NP 100V H capacitor. I want to avoid working on the board twice.

Have you recapped the analog board yet?


I’ve seen that when I had a poor flyback anode connection to the CRT.

Update. It was the flyback anode connection that was indeed the problem. Thanks!

 

[Marconelly]

I've had similar flickering on the Color Classic, although it involved color changes and instability. Much like yours, it was most pronounced during the warmup period of 10-15 minutes. Problem went away after I recapped the analog board (I did a full recap) and also touched up any suspicious larger solder joints on the analog board and the CRT neck board.

 

[asphaise]

This looks very similar to the issue I just dealt with. I suggest you read the whole thread I've linked below. It isn't very long and there is some good information from some very helpful people. In the end, replacing one transistor, BU406, solved the wobbly screen problem I was having. It wasn't difficult and my soldering skills are essentially non-existent.

https://tinkerdifferent.com/threads/recapped-se-30-occasional-horizontal-screen-shake.4254/