Client monitor with Sony DSR-1500AP

One of our Avids systems is going me crazy. This is the problem:

I have a Sony DSR-1500AP deck attached via FireWire to a dual xeon PC running XP SP1 with XPress DV 3.5.4. I can record to tape without problems. I can see the tapes playing in the 1500 with a PAL monitor via composite without problems. But if I try to see the signal of the timeline through deck in the PAL monitor, the image shake all the time. Sometimes, when I restart the computer and the deck, the problem disappears, but sometimes there is no way to fix it.

I´m thinking this issue could be a deck hardware problem. I just try with other deck (DSR-11) and a miniDV camera, and everything works great.

I restored default DSR-1500 settings and changed several internal settings, but I never get stable image at the composite output.

Anyone is running sucesfully a configuration like this? (Xpress 3.5.4 & DSR1500AP)

Thank you.

Juan