So, I have 2 3/50 boards I'm trying to resurrect. I thought one was good (passed diags with diag switch on). The other I know has a bad ram chip. The one I thought was good... gets (as one example): MEMORY ERROR! STATUS D4, DVMA-BIT 0, Context 0, Vaddr: FFE10C, Paddr: 003FC10C, Type 0 at 0FeF4C88 It gets several of D4, D2, and D1 when it attempts to boot, or if you interact with it at the boot PROM. I did try changing the large socketed (MMU + more) chips from the board with the bad memory chip... same behavior. I have not tried changing CPU, FPU, boot rom, or any PALs. As for the one with the bad ram chip, it fails quickly on power up with: Memory Parity Data Test Err 2: Addr 0x00000400, Exp: 0x00000001, Obs: 0x0080001, Xor: 0x00080000 I've not found any memory map to help me determine which chip this is. 0x00000400 is the 1024th byte of RAM... so I'd suspect the first bank... but which bank that is I don't know. Anyone have a 3/50 memory map so I know which chip to replace ? Or a good technique for figuring that out ? Thanks in advance, -- Curt