Some time during it's history, this droid was captured by the Death Watch terrorist organization and brought to their encampment on the planet of Carlac, where, along with other captured droids, was used as target practice for the Death Watch soldiers and had most of it's components removed and replaced.
When junior senator Lux Bonteri arrived on Carlac along with Padawan Ahsoka Tano and astromech droid R2-D2 to deliver a holotrace device with the location of Separatist leader Count Dooku to the the Death Watch, R2 was ordered by the soldiers to fix all of the damaged droids, including this one, to be used as target practice again.
After the Death Watch attacked the Ming Po town and Ahsoka's true identity was revealed, she along with Lux were brought back to the camp and faced execution. Fortunately, R2-D2 had finished repairing the droids and had assembled them to fight against the Death Watch, allowing Ahsoka and Lux time to escape. In the end, after the firefight broke out, all of the droids were destroyed, but Lux, Ahsoka and R2-D2 managed to escape the camp and subsequently, the planet.