If you own a Marshall JCM 2000 DSL 201 or 401 this is a mod you should consider. The problem is a bridge rectifier installed on the PC board with no space between the rectifier and the board. The rectifier produces a lot of heat and often eventually damages the solder joints on the back side of the board causing intermittent or open connections. This in turn causes a loss of high voltage DC current to the circuit that results in the amp cutting out or totally losing output. The cure is to replace the existing rectifier with a new rectifier with longer leads mounted with ample space between the PC board and the rectifier. The longer leads are soldered to the traces on the back side of the board after insulation has been stripped from the traces to provide a larger solder pad. This creates a much larger and stronger solder joint and, along with the newly created space between the rectifier and the PC board, totally eliminates the heat problem.
The component side of the PC board showing the bridge rectifier mounted above the board with ample space to keep the board from getting hot. It also allows for ample airflow around the rectifier.
The back side of the board showing the extra leg length soldered to the pad and trace. The contact area is greatly increased making a much stronger solder joint.