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That error is said to be a voltage or controller board error. Or sometimes a printhead error. The information I get is not too specific. But one post says it is definitely the controller board (in that poster's case, anyway.)
Since you have already tried a power-Off reset, then perhaps
1. re-seating the printheads
2. checking power supply voltages live/under-load
3. re-seating the cable between main controller board and carriage relay board