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BSU Timing Logic Circuit Board

Technical Information

Catalogue No: C0936
Category: Surveillance/Acoustics
Object Type: Module/Sub-Assembly/Component
Object Name: BSU Timing Logic Circuit Board
Part No: 6743-00343-01 Iss C
Serial No: 108
Manufacturer: Marconi-Elliott Avionics
Division: Maritime Aircraft Systems [MASD]
Platform(s): Merlin AW101 (EH101) 
Year of Manufacture: Unknown
Width (mm):
Height (mm):
Depth (mm):
Weight (g):
Location: Main Object Store

Marconi-Elliott Avionics
MRB No. 240/00990
MRB No. 240-00861
Pt. No. 6743-00343
DL Iss C
Ser No 108
Mod Record -
AAB P30/5
CE23837 Iss A
LAB P16/2


AQS-901 was given full development go-ahead in April 1975 as part of the British Nimrod Mk 2 programme. The scale of this contract merited the formation, in 1973, of a dedicated Maritime Aircraft Systems Division (MASD) which was prime contractor, with Computing Devices Company of Canada as major subcontractor.

AQS-901 can collect information from up to eight sources simultaneously and a wide variety of active and passive sonobuoy types. The AQS-901 main computer was a version of the Marconi-Elliott 920 ATC, with a nominal 64,000-word store which is expandable up to 256,000 words. Bulk memory units provide extra capacity. The system converts sonobuoy data for presentation on electronic displays or multi-channel paper recorders.

The system would also be fitted to the Royal Australian Air Force’s P-3C Orion maritime patrol aircraft. The AQS-901 system ultimately consisted of 20 units of electronic equipment which covered radio receivers, buoy signal processors, computer units, controls, CRT and Hard Copy displays. Both the Nimrod and Orion aircraft carried two complete sets of these plus another shared CRT display, control unit and a radio transmitter - 43 items in total. Each aircraft had an acoustics station seating two Sonics Operators and a Tactical Coordinator.

This is the BSU Timing Logic board

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