Not the cause of the problem that it is here for repair, but I cannot return it to the owner with this glaring potential (in both senses) fault, presumably the same for all such Warwick amps. One large heatsink with +75V on it and the other at -75V and 2.5mm between the two , both mounted on standard polyester pcb with chassis standoffs well away from the heatsinks. Discharged both before this test of course, requires only 1.5Kg of force between the 2 heatsinks to narrow the gap to
1.5mm. Have amp designers never seen the internals of their stuff resonating/oscillating mounted in or on speaker cabs, especially bass amps such as this?-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on