Sorry TBM but can you confirm you have a normal self contained alternator and not the very old Lucas ACR system which has alternator plus three external components, a control unit, dedicated relay and warning light device - as fitted to Mogs 69 - 73 I believe. If the former then some disassembly is required to locate and identify the diode trio. All the diodes (nine in total) typically sit on an insulated board behind the back cover.
