[Amps] Harbaugh SB-220 Cap Bank Diodes

[Jim W7RY]

I just had a catastrophic failure on a SB-220. (There was no glitch resistor installed YET). I had a rubber foot from the amp wedged between the interlock spring and the choke standoff.  The foot apparently broke down and started to arc.

Didn’t blow the breakers in the panel or back of the amplifier, but took out the step start resistors. 

The event also shorted half of the diodes that Harbaugh puts on across each filter cap (the lower set of caps). The rectifiers are all fine, it has a Harbaugh diode board too with 3 amp diodes.

What is the wisdom in putting diodes (1N4005) diodes across each cap? Obviously the caps suffered reverse polarity. 

Thanks
73
Jim W7RY