[alanworland]

Interesting. This afternoon I disconnected the cartridge terminations and shorted the signal to earth leads, hum was non existent but once reconnected it returned. So at least I know my coiled up pickup lead under the arm is not a cause - it's being picked up by my V15.
Also then removed the plug fuse which greatly reduced hum as did fitting a clip on choke that I found in my parts box. So as I haven't been able to find my screened cable I have ordered a short length of Belden screened cable to replace the deck mains cable up to the motor junction box.
Does the forum consider wrapping all under deck mains wiring in a earthed copper screen would be beneficial?
If none of this works I could turn it into a clockwork deck!

Thanks for the strobe link but my strobe is now 'normally off' until I press it so won't be radiating any spikes.

Alan