[Milsurplus] [ART-13_Transmitters] Working on my ART-13's

[Mike Hanz]

On 2/14/2012 12:39 PM, J. Forster wrote:
> Pull the HT brushes on the dyno and bring the HT up to spec slowly with an
> external, current limited, DC supply. If the caps then fail, you will not
> have collateral damage.
>
> ==============
>> I have a Ballantine DY-17/ART-13A dynamotor, as
>> well as a DY-17A. Unfortunately, the -17A is under a pile of heavy stuff
>> right now, so I started out with the old, beat-up -17. I did the usual
>> bearing cleaning and relube, and turned it on. Overload and groan. I found
>> the 400 V and 750 V brush filter caps shorted.
>>
>> I hate the thought that I may be forced to build an AC power supply for the
>> ART-13, because I like to run military gear the way the original system is
>> set up. I don't mind the whir/whine of a well-lubed dynamotor  :-)

John's excellent suggestion is what I use as well.  I'll admit I didn't 
worry about it for years, but in the last decade or so, everyone seems 
to be running into capacitor failures - even with those caps that seemed 
bulletproof a few years ago.  I take it a step further and leave the 
current limited supply turned on for several days, then use a heat gun 
or hair dryer to warm the caps up a good bit for a few minutes (if they 
are still alive).  If they're going to fail, it will be in that final 
heat cycle when you can watch the leakage current.  They'll get up to 
the temperature of the dynamotor anyway, so if they're gonna do it, you 
want them to fail before they do it while transmitting.  Just a little 
too hot to touch is a good test environment - 130-140°F.

Just something to consider...

73,
Mike