Those screws are chinese (Fang Sheng) and probably take a Metric Allen wrench.
How do I open VAC Standard LE MkII chassis?
I would like to check what tubes are being used in my VAC Standard LE MkII preamp. I have tried Allen wrenches, Torx, and other small sets gently and nothing is catching to be able to unscrew the screw. Taking a close photo the screw heads say YFS and while they look a little bit like hexagons they also look kind of stripped.
Any advice for how to unscrew these as I attempt to do this without scratching the top of the unit?
Thank you so much,
Thank you @fuzztone and tha@rodman99999 I appreciate your replies and will try to find a metric Allen wrench to test out.
Easy to find at any Hardware Store, Home Depot, etc, or: