One of the electronic control units in a Class 50 locomotive is the CU5 radiator fan control unit. It works together with the CU4 coolant flow control unit under the control of the CU1 main control unit to maintain the correct cooling water temperature by adjusting the speed of the radiator fan. Both RRRG's locomotives are missing this unit. The original was designed by Hawker-Siddeley for English Electric and utilises components that, by the standards of the 21st century, are thoroughly obsolete.
A good friend of RRRG, based at the Gloucestershire and Warwickshire Railway, offered his services to construct a compatible replacement unit using modern electronics - needless to say, we were and are extremely grateful for this offer! Shown here is the item which is now nearly complete. The main circuit board has been deliberately left unattached to the case at this stage, as the next step is to test the unit by connecting to a suitable 110 volts DC source in order to ensure it performs correctly.
An original unit was borrowed from the 50021 Loco Association, and this new unit has been produced to resemble it physically, while using greatly-simplified circuits (as the original was over-complex for what it needed to do), modern components and utilising a small programmable microprocessor to replicate many of the functions of the original. We will provide more updates on this sub-project when they become available.