Chosen Solution
This is a Mac SE/30 which once worked but has bee in a loft/attic and the screen is very distorted although you can make out enough to see that it otherwise works.
Obligatory CRT safety warning: CRT monitors can hold 15-25k volts (15k is the average for desktop class CRTs, 25k for TVs). If you repair it, DO NOT TRUST THE BLEEDER RESISTOR! Discharge it yourself! Refer to this previous Answers post for safety info. You might want to read my answer I’m linking, and the backlinked answer within the answer. Pray it’s the caps - the compact Mac analog boards are known to have issues there. See if you can find a capacitor rebuild kit that ships with Nippon Chemicon or Nichicon caps and recap the analog board and seriously pray that fixes the problem. Try and go for Nippon Chemicon, but Nichicon is also good. Do not buy any of the cheap ones like CrapXon - they don’t hold up very long. If it isn’t bad caps, the flyback needs to be replaced. Usually when the flyback fails, the cost to get the bare flyback vs. a properly refurbished analog board (new Nippon Chemicon or Nichicon caps, and checked for other issues) leans towards a new analog board. The bare flyback is quite rare, compared to refurbished analog boards.
You can get the replacement capacitor kits here: http://www.maccaps.com/MacCaps/Repair_Se…
Your Mac uses a CRT so unless you understand how a TV works and use the proper precautions High Voltages - you can be seriously hurt here! Its best to let someone with the skills to tune your CRT display as I’m sure the flyback transformer and caps have aged and may in fact need replacing.
