Marshall Major Mods

An early backup Major from Ritchie

Ritchies backup Major topside

Major untouched from 1970

Major detail

Major detail

Major early 70s years

Fixed Major

Fixed Major detail

Fixed Major detail

Heavy modded Major

Heavy modded Major 1969

Main transformer Major

Electronics Major

Recapped Major

Here the four mods to get the Major stable. See the details in red circles in schematics

First: Insert the OT protector diodes like shown.
Second: change the 4 pieces screengrid 250_Ohm Rs of KT88 to 1kOhm/ 10watt
Third: change the bias caps (2x 8uF) to 2x 47uF/ 160Volt
Fourth: change the feedback resistor (47kOhm) to 150kOhm

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