PDP-8/E Ext. Memory Test Wierdness

My PDP-8/E currently has four fields of core installed - fields 0 through 3. All fields pass both the 4K Memory Address Test and 4K Checkerboard Test with no problems. The Ext. Memory Address Test also runs fine. However, when I run the Ext. Memory Checkerboard Test I get wierdness. Here is the run: PDP-8E EXT MEM DATA & CHKBD SETUP SR & CONT <--- Set SR to 000000000011 4 FIELDS IN THIS SYSTEM FIELDS SEL'D ARE 6 5 3 2 0 <--- First bit of wierdness. This should be 3 2 1 0 PROG WILL RELOCATE PR LOC FAIL ADDR GOOD BAD PATTERN 01660 50000 7777 0000 ALL 0 - 10 01660 50001 7777 0000 ALL 0 - 10 This continues through fields 5 and 6 until I hit the halt key. The Config is as follows: PDP-8/E CPU EAE Ext Memory & Timesharing ASR-33 Teletype and Associated Control 4K Core stacks for Fields 0 and 1, 8K Stack for Fields 2 and 3 What I don't understand is why the Ext. Mem Address Test works correctly, but the Ext Memory Data and Checkerboard can determine the number of fields while messing up on exactly which fields they are. Anyone seen this before? -- Christopher L McNabb Operating Systems Analyst Email: cmcnabb(a)4mcnabb.net Virginia Tech ICBM: 37.1356N 80.4272N GMRS: WPSR255 ARS: N2UX Grid Sq: EM97SD