Analogue-sequencer

Hi
 
Hooray, my new P3 is sitting here and I'm working through
both manuals. :) I have a micron keyboard, I think set up
properly (local control off) P3 thru on. Everything is
working fine - I can record notes from the keyboard, 8 diff
patterns playing on 8 diff midi channels, different lengths,
yeah sweet.
 
But , following Paul's instructions, in ARP record if I
press the keyboard the left hand display P: n just flicks
between 1 and 9 and doesn't pick up the 3 note chord I'm
playing, same with rong on or off. All the step lights come
on but they just play the same note -du du du dud du.... So
what's happening here? 
 
I'm not 100% familiar with the micron as it arrived the same
day as the P3, but its the only keyboard I have access to
right now, maybe something is set wrong but I can't really
think what, it seems straightfoward enough and is working
fine in the other record modes
 
I'm on OS, errm dunno, the one that was current last
week....3.1.005?
 
Richard