The nameplate has a phone number, did you try calling it?
My guess is that this is a monitor that has been "put together" by one more of a few companies that managed to find boards that were left in circulation when Pentranic USA closed? ALS, Budget tubes, who knows, the black metal frame suggests that any way?
It uses a CH288 switchable chassis originally made by Rodotron, but may be a copy as for the past number of years we are the only company in North America Rodotron would sell to.
No matter, back to your questions:
-red, green, blue self explanatory ... color signals
- black is ground
- yellow is Horizonatal sync if separate sync is used, composite sync (Vertical and horizontal) otherwise
- white is vertical sync if separate sync is used
As it appears IC1 is installed to the board this monitor "should" accept either separate or composite sync.
BTW if using AVGA for mame at "standard resolution" be sure the jumper on the stand-up board on the heat sink is set to 15k. Do not move it with power on.
Hope that helps.
Good Luck
Rick Nieman
President Nieman Video Displays