Marshall AVT50

24V fan would seem to be variable to temperature sensed by thermistor close to but not touching the heatsink at the o/p hybrid and no trace of white goo. Going by the number of problems actual and potential on this less than 2 year old PbF amp, has someone omitted some goo at assembly? The green silipad under the TDA is puffy as though overheated , fan supply works but does it work properly with thermistor positioned 4 mm from the heatsink, just monitoring air/ board temperature ? Touching thermistor with hot metal brings up the fan speed.

No abuse. In for failed 1/4 inch input socket, failed spring action on shorting switch/ signal contact, all other sockets would start to fail in a couple of years, used or not because of inadequate solder. Solder on a number of W/W going home, one failed on touching it, push on power handling connector pins did not survive normal hand force of being pulled off the posts, more solder failure, posts came away with the sockets. Force between pin and socket more than the pcb solder strength. At least the clean/dirty switch has an oval knob and close tolerance panel hole so that may survive longer than the rectangular ones in other Marshalls.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on