[AMPS] Diode PIV

[nospam4me@juno.com]

> I bought a couple of diode stacks at TRW and was told 
> they were 15kv

Most of the time, I use 1n5408 diodes in my repairs and 
newer projects.  There is an similar diode package I obtain 
from a very local parts house which are spec 1200 v @ 6A 
continuous. 

My friend who owns the parts house, bought a barrel of these 
from a mfgr many years ago.  He tests a large batch at a 
time with a home brew current limited curve tracer. 

The diodes are ramped up to 1kv min, often 1.2kv or to the 
point where the reverse diode current starts to avalanche 
(but is current limited to a few micro amps).  The diodes 
are removed from the fixture and placed in labeled bins 
which indicate their "performance" in the fixture.  The 
process doesn't seem to hurt the diodes, in fact... he told 
me the diode mfgr is the original source of the procedure. 

I've never had a bad diode from him in the many years I've 
purchased them from his (now private) parts supply house 
in Sacramento.  The barrel of diodes were rated at 1.2kv, 
6 amp each. Verbal from my friend Bill, about 96 percent 
of each test lot make the 1.2kv spec.  The extra 3 often do 
1kv with a few stragglers <1 percent at the 800 volt value. 
Most of the prime parts will actually make 1.4kv  

Vintage solid state high power audio amplifiers love to 
eat diodes during heavy road service. My mov, diode, 
bypass retrofits would keep them out of the shop until 
they clogged with dust/dirt/hair and the fan stopped. 
Sometimes the band never noticed part of the pa had died. 

cheers
skipp
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