It switches on for about a second and then relay clicks and it switches off. VCR loading mechanism operational manually.
When ribbon cables disconnected to circuit above power board it clicks on and off repeatedly. D1150 replaced and switch on the VCR loading mechanism cleaned.
Check D1150 is the right way round.
There's a comment in this thread about checking the forward voltage drop when passing a high current. Might be worth a punt, I have known replacement components to be faulty from time to time. (Used to work on a test bench)