Side B Atari imaging problem

[claycowgill]

You can't have GX jumpered... that should be on EX.

None of my drives have MS jumpered.

My drives have the following jumpered:

DS0
DS2
EX
DC
DA
IE (with a permanent wire on the PCB)

Hmmm.  Not sure what to say, but I've had GX set for the entire time I've had the board and it's been producing working images and writing disks OK, so that's a head-scratcher. ;-)

I have:
DS1
HM (hardwired)
MS (seemingly required or drive won't spin)
GX
DC
DA
IE (hardwired)
PH
RY (hardwired)

If I remove the GX jumper and place it on EX I get an error at about track 11-12 "Read Length > RAM Capacity" on the B-side image I'm trying to pull.  When I try that configuration on another A-side disk that is known good and was imaged successfully earlier (with the GX jumper on) I get that same 'read length' error at about Track 35.