Things you should have done (not helpful ;):
- Somehow find out the voltage and pinout of the 4-pin (?), possibly from a similar camera model from Ikegami and then beep out the connector with a multimeter
- Find a known good PSU (likely 12 or 20V). Not this one (too expensive): Blackmagic Design Netzteil für Ursa Mini Pro - Teltec | Video-, Audio- & Studio-Equipment zum Bestpreis But something like that. Cheap from Aliexpress or used from eBay or classifieds for old broadcast gear
- First find out if your Gold mount PSU catches fire before connecting it to the camera
- Not even thinking about touching any potentiometer inside the camera without owning test equipment like an oscilloscope
Okay, with my nonsense out of the way… What you should do and where you’ll find friendly expert help:
- Join the VE Discord. Video Engineering I bet there are a couple of nice people who can help you assess the situation. Very likely they can also help you firm a cheap-ish working camera from that era, if you just want to learn how to use it and to document it.