Repeater Overdub Problem

[DaViD AuKeR <DavAuk@Hevanet.Com>]

I really dig "dueting" w/myself - subsequent overdub runs thru a loop
coming back at me as I then harmonize. I KNOW I've done this w/Repeater,
but I only seem to be able to do this *sometimes.*  

I have a couple of tracks playing, and I'm overdubbing on a  track that
already has material recorded.    Most of the time, I only hear the most
recent layer, and then only when "record" is turned off, any feedback
'die-down' of original material only apparent then.  Any ideas on why
this is a hit and miss operation for me?   It doesn't matter what the
feedback is set at....I'm on the card, and memory is ample.

David