The following was excerpted from a fax received from the licensee:
NLI manufactured the reverse engineered units to replace the existing obsolete electronic position controller NLI Model: NLI-10A-LM-P.
The failed component within the controller was sized based on the original published ratings of the original components installed. The unit had an internal component that was subjected to a current value that was higher than the rating for the component. The actual applied current value was not originally provided to NLI when the units were being designed. NLI and the affected plant has been in communication regarding the component condition since the first reported failure.
Three of units that initially failed in the plant have already been returned to NLI for failure analysis and design modifications. These units were modified by installing a larger bridge rectifier and wire wound resistor onto the revision 0 circuit board. The modified versions, quantity of three, S/N: NLI-10A-LM-P-1003- 0, NLI-10A-LM-P-1004-0 and NLI-10A-LM-P-1006-0 have been returned to Calloway under purchase orders 689233 SR and 694253 SR and have been accepted and installed into the plant and are working with no reported issues.
The model number NLI-10A-LM-P, has been redesigned with a larger bridge rectifier of a higher rating and wire wound resistor that will withstand the applied current in the intended application. The parent circuit board has also been revised to revision 1 to accept the larger bridge rectifier without impacting other components on the board.
The remaining unmodified revision 0 units that were originally supplied have not yet been returned to NLI for incorporation of the design modification. NLI recommends that at the plant's earliest convenience, the remaining units be returned to NLI to be retrofitted with the latest design configuration (revision 1 circuit board).
The affected plant is Callaway.