Dolphin diagnostic power switch trips when attached to Dolphin unit

Had no problems with dolphin diagnostic. I changed propeller blade a few times, along with tracks but never had a problem. Just opened the pool, ran dolphin as normal then today placed in the water and power supply switch trips out when power turned on and dolphin cable attached. When cable not attached, power unit doesn't trip. No obvious cuts to cable to dolphin. Tracks turn easily by hand with no obstructions. Any thoughts? Any benefit to disassembly of dolphin unit?
Thanks,
Perplexed in NJ

REPLY: Problem is most likely a broken wire or two in the cable. Most likely point is where the cable enters the robot as it is subject to lots of flexing.
Disconnecting the cable at the robot and performing a continuity check on each wire will diagnose it.
Best test to isolate the problem would be disconnecting the cable at the robot motor housing and after ensuring the bare ends don't touch, power up the cable.
If the power supply trips off, then the problem is the cable. If the power supply does NOT trip, then the problem is in the motor housing and can't be repaired...only replaced.