Dragon 32 weird screen.

[flaviosr]

I just tried my old Dragon 32 and... tragedy! A strange weird green screen.
It changes and can have more or less chars. I have tried to look for similar issues but I have found only plain green screen.
Any ideas?

 

[jltursan]

I've found quite some Dragon machines with busted 6809 CPUs; but usually more "at" chars appears on screen.

Also, there's a 10K variable resistor with vertical mount that also gets some strange debris, like crystal and causes screen havoc similar to the one you posted. The resistor is located near the connector between main board and PSU board, try to thoroughly clean it with IPA if it's dirty (mark with a pencil its original adjustemnt!)