Sounds like the Power Module board has something wrong on it.
When did you have the system installed? What is your serial number on the DIG-220?
Is everything else working?

Please check the cell fuse again (top left corner - white ceramic fuse), then check the wires going from the top left to the cell banana jacks.
Check your wire harness that goes between the two circuit boards. It may be a loose wire in the wire harness. The wires should be pushed into the connector terminal fully.

A worn cell or bad cell cord would give you a 29 amp reading. 0 volts and 0 amps are indicating that the cell is not getting a signal to power up.