The boards are old. How many of us have a 15 year old computer that still runs? Buy the PS3-2 replacement board and you will be in good shape. The boards are old and nobody should be astonished. I have many in a box and will not sell one because the thing will usually come back and bite me. Over the years I have had George (GGG) Galyo rebuild many PS2 3V boards and I replaced the 5 V boards with the newer better board. Today we have available the PS3-2 board that will replace the old 5V board. That is also the hot set up.
I tell people who find a 5V board to use a new fully charged green MTH battery. NEVER and I mean NEVER try to get it done with an old white battery.