Yuri, The M4G5 is a 600 Volt, 3 amp diode. I would replace it with a 1N5408 which is a 1000 Volt, 3 amp. The case style is different but is the same type (rectifier) diode. Will Matney Hi, anybody knows if M4G5 diodes(used in Drake L4B amp. PS) are still available? If so, what is the source? I don't need many, just a few. Thanks. Yuri VE3DZ