Great place to send in for repair:
Sharp Image Repair
Read on to try to repair yourself.
I had a good conversation with a user on the arcade forums (https://forums.arcade-museum.com/threads/kortek-monitors-tips-tricks-and-cap-kits.157123/page-13#post-4244149)
The symptom were it was clicking on and off like a turn signal.
I replaced the following:
- Vertical Deflection
- Q712 Hot Transistor Part # Panasonic C5584 (pulled out and it had continuity between pin 1 and pin 3. This means it is bad.)
Apparently the scan transformer at T303 (Part# Sct-82D) has a tendency to fail. There is no replacement at the moment. Heavy burn marks on the motherboard are an indicator.
I also had to replace the red wire from the yoke it was black and brittle from overheating.
Q710 should test at 250v DC.
Other locations to check (pull the part and test) are R748, R732, Q706, Q708.
The flyback is still available but mine was not needed Part# FFA76418U (has a dual focus)
DO NOT ADJUST THE SCREEN KNOB. When doing that it blew my Hot and made the clicking sound. Not certain it was the cause but that transistor failed shortly after messing with that knob. I hot glued it in place.