Found the M9006 unit assembly, which includes PCB etch, in the MA20 and
MB20 FMPS, and a diagram showing the signal assignments for the Cbus & Ebus
on CPU backplane slot 54 in the RH20 FMPS.
MA20 FPMS, pages 58-62:
http://bitsaversorg/pdf/dec/pdp10/memory/MP00010_MA20_Schematic_Jul76.pdf
MB20 FMPS, pages 70-74:
http://bitsavers.org/pdf/dec/pdp10/memory/MP00179_MB20_Schematic_Aug76.pdf
RH20 FMPS, page 64-65:
http://bitsavers.org/pdf/dec/pdp10/KL10/MP00056_RH20_Apr81.pdf
AB54 is the M929, and CD54 and EF54 are the M9006. Note typo in
designation of F54 on page 65.