"n cook" bravely wrote to "All" (19 Jan 06 09:11:40)
--- on the heady topic of " Marshall 4140 Amp question"

nc From: "n cook"
nc Xref: core-easynews sci.electronics.repair:355765

nc Amp is 1975 , from electrolytics, and uses Si rectifiers.
nc Amp was in a damp shed for maybe 15 years. Doesn't look too bad for
nc that , after blowing out the cocoony bug nests etc (1KW Martingdale ).
nc Charred/burnt 1.5K grid resistors and blown HT fuses.
nc All valves ( all marked Marshall) checked out good on Avo CT160 - I'd
nc forgotten how problematic , with high current valves, to get the
nc initial zero on the meter before rotating the SET mA/V.
nc I always power up kit left idle for a long term with a variac +
nc current meter + thermal trip.
nc Is it still perceived wisdom in such circumstances to power up valve
nc amps with full speaker load on output with all valves in place and to
nc power up transistor amps intitially without load ?


The burnt 1.5K grid resistors might indicate the last user tried to
operate the amp without a load and after the smoke out set it aside.
You are a wise man. Why did you need our help again?

A*s*i*m*o*v

.... The current limits placed are based on resistance