Here's what the KVS Tool's WSpan operational info for the flight says, my notes in italics:

[KVS Availability Tool 6.1.2/Diamond - WSpan Operational Info: US 796/24 Apr 2011]

0796/24APR
P LAX/OUT 1103A E00:07
P LAX/OFF 1116A
P PHL/ON 658P
P PHL/IN 702P E00:18
P PHL/OUT 911P E00:04 Left the gate 4 minutes early.
P PHL/ETO 1015P Initial takeoff estimate.
P PHL/RR 1041P Returned to gate. (RR = Return to Ramp?)
P PHL/OUT 1145P L02:30 Second gate departure.
P PHL/OFF 1206A Takeoff.
P TLV/ETA 526P L02:11# Estimated arrival.

Given poor weather this evening that backed up departures and a mechanical, being only a bit over 2 hours late into TLV wouldn't be too bad. And I'm sure they wanted to fix whatever the issue was before flying 5500+ miles.

734 to MAN also returned to the gate and is also under way again. I don't know why.