OFA has a list of all cinema 7 codes at their website: [Link: oneforall.com]

According to that, Cable/0770 is 'Prelude', so it should work. The only thing I can think of is, did some other function get assigned to the cable key? try this (see [Link: oneforall.com]) and then try again:

PRESS the device,(TV,VCR,CABLE,etc.), button - RELEASE
PRESS and HOLD the MAGIC button until the red LED flashes twice, then RELEASE.
PRESS 9 - 9 - 2
PRESS the device button twice. - Two blinks.