SD-700/720 supplies all essential services required to accommodate effective air/ground communications through the satellite, using the antenna and related RF components. Radio Frequency Module (RFM) is a module in SD-700/-720. The SD-700/720 has a low reliability issue as a result of Radio Frequency Module (RFM), PN 7516113-905 failure. The root causes are, 1) the final Radio Frequency (RF) amplifier failure, which is caused by the impact of metal trace migration to the amplifier, and 2) the Complex Programmable Logic Device (CPLD) construction that can allow for irreversible die failure.
The new RFM, part number 7516113-906 addresses both final RF amplifier and CPLD issues. The forward fit SD-700/720 has the new RFM (-906) that has increased reliability. The fielded units will be replaced on an attrition basis when the SDUs are sent to Honeywell shops for repair. The Honeywell repair shops will replace the existing RFM, PN 7516113-905 with the new RFM (-906) per the Service Bulletins (SBs) on failed SDUs Free-of-Charge for 60 months following the SB release.
Two Field Service Bulletins (FSBs) have been released:
C21-5115-013 (Oct 22, 2012) and A21-5115-011 (Oct 18, 2012)