Dolphin Erratic

by Peter Phillips

Dolphin Dynamic plus four years old. Put alway last october clean. Come to house and pool and tried for first time yesterday. Found problem. Taken everything apart and there appears to be no problems, but the following happens.

When it Drives one way both side tracks work, but reverse only one side track drives. It uses both drives when turning but only one side drive the other.
Removed sides and everything is free.
What is the problem?
ADMIN REPLY: Electronic Control Board