The Amp Repair that Almost Broke Me - Marshall JCM800 Combo

Описание: This is a rare 1986 Marshall 4210 - the 112 Combo version of the 2205 Split Channel Reverb, 50W head - that just would NOT cooperate. It had multiple issues, but the main symptom was that it was eating V3 tubes like Halloween candy and, I would soon discover, had almost ZERO output as well and had issues with the switching. When working properly, these amps have that Judas Priest, early Metallica NWOBHM thrash tone many of us old timers grew up on, but will this be the amp that finally breaks me?
Preamp Schematic: http://drtube.com/schematics/marshall...
Power Amp Schematic: http://drtube.com/schematics/marshall...

Although it has the JCM800 badge, the 4210/2205 circuit is less of the JMP pedigree and more of a precursor to the JCM900 series with its diode clipping circuits in the Boost Channel.
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