[Amps] Meter issue

[Paul Decker]

I've been trouble shooting a problem in my amp with the Ip and Ig metering.  I've got parallel 1n4004 diodes with opposite polarity accross the meter terminals of each Ip and the Ig meter, nothing new, pretty standard. 



It's easy enough to replace the diodes, but what would cause one of the diodes in both meters to fail in the shorted case?  There are no other apparent problems and the amp still works save seeing the meters deflect. 



Thanks 

Paul