[R-390] [Fwd: Reconditioned Amelco R-390A Part Failure]

[Al Parker]

Hi folks,
    We've been seeing that sort of thing in SP-600 chokes.  They're big, 
heavy, potted, but some do short to the case.  Some folks, living 
dangerously, have just mounted them up on insulators (I hope they insulated 
the case from fingers).  The potted pwr xfmrs have been pretty reliable. 
Audio xfmrs have gone, but usually due to leaving the secondary open when 
using fones or external amp, etc.
73,
Al, W8UT
New Bern, NC
www.boatanchors.org
www.hammarlund.info

----- Original Message ----- 
From: "Bob Camp" <ham at cq.nu>
To: "Tom Frobase" <tfrobase at gmail.com>
Cc: <R-390 at mailman.qth.net>
Sent: Saturday, March 22, 2008 3:15 PM
Subject: Re: [R-390] [Fwd: Reconditioned Amelco R-390A Part Failure]


> Hi
>
> Magnetics do indeed fail just as you describe. It's not uncommon in  older 
> gear. My guess is that eventually we will start to see power  transformers 
> fail in the same mode.
>
> Bob
>
> On Mar 22, 2008, at 2:44 PM, Tom Frobase wrote:
>> <snip> >>
>> The problem ended up being the 12MH inductor L505, shorted dead to 
>> ground.  Go figure in thirty years of repairing these things I have 
>> never seen that before, has anyone else?
>>
>> tom, N3LLL
>>