My Apple II Memory Expansion Card (which has 256KB onboard) is not detected by ProDOS as a RAM drive. It's presently in slot 4 of a Platinum //e and when I run Copy II Plus to format it as a ProDOS block device it succeeds but when I access the drive it says it's not recognizable as a DOS 3.3 or ProDOS device. I can verify the drive using Copy II Plus and it appears to be the right volume size (512 ProDOS blocks).
I've tried replacing the RAM modules with known good one's but that hasn't made any difference. Any ideas ?