AS/400e 170 IPL failure

Hi folks

I'm new to the list and hoping to find some help. I recently bought
two AS/400e 170 systems, "doublewides" with expansion chassis. One of
them completes IPL just fine but the other fails. On visual
inspection, the only difference I can see is that the one that
succeeds has three drives in the expansion chassis, while the failing
one has only one. Both have four drives in the base chassis.

On the failing one, I've tried B N, B M and A M, all with the same
result. SRC 11 shows 27409021 (about which I can find little, except
that the red book suggests it's a hardware issue and the list of SRCs
says that 2740 xxxx may indicate a storage IOA failure) which then
changes to A1003022. SRC 22 also shows A1003022, which appears to
indicate operator intervention required in the Service Processor part
of the IPL and may mean that AIX wants to do a dump.

Working on that assumption, I've put an unformatted CDRW in the
optical dive, a used tape in the tape drive, selected 22 and hit enter
a couple times and got D1003080. This is neither the D1823080 to
indicate dump accepted nor the D1068000 to indicate dump not enabled
that the book told me to expect. It does show some changing numbers,
for a while, but it ends up back in the same state. So I may be wrong
about the AIX dump.

I do have a list of all the SRCs that it's throwing, but it's at my
workshop. I'll post it here when I go there later today.

I can't do a D M, because I don't have any media, so does anybody have
any ideas what I might try next?

Thanks
Robert