9903-543 505 & 505E Control Internal Power Supply Issue

An internal power supply issue has been detected in a small population of 505 and 505E controls. This internal power supply issue can cause the controllers CPU to reboot and stay in its reboot mode, resulting in a safe shutdown of both the control and turbine.
Woodwvard has identified a small population of 505 and 505E controls (less than 2.5%) that have been returned for service due to a continuous reboot condition caused by a low internal 5-volt power supply. It has been determined that the main contributing factor of this issue is the mechanical connection between the controllers internal 5-volt fuse and the fuse clips inline with the unit’s CPU.
The potential failure modes of an affected unit results in a safe shutdown of both the controller and turbine, with the controller’s front panel typically displaying ‘Testing RAM…” while continuously rebooting. This reboot condition may also occur during any phase of the control’s initialization routine as well, so the actual text displayed may vary.
The following 505 and 505E control item numbers manufactured between December 1, 2003 and June 29, 2004, are susceptible to this internal power supply issue.

Woodwvard has implemented process improvements, and an engineering change to the controller’s power supply module to prevent the issue from occurring.
If it is determined that a unit needs to be returned to Woodward, please select one of the following options:
* Contact your Woodward customer service representative for a return authorization number (RAN) and return the unit(s) to Woodward.
* If a return is not feasible, contact your Woodward customer service representative to discuss the availability of replacementlexchange unit(s).
I Please refer to this service bulletin number when scheduling your return. I Service bulletin actions will be performed at no charge within the product warranty period.