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

[J. Forster]

Thanks Mike,

I should have added that. I leave the supply connected for several hours
at least. If there is no smoke coming out of anything, I kill the B+ and
feel each of the caps to see if they are warm/hot. It is unwise to do this
with B+ applied, IMO.

In many sets, this is easy because all you have to do is not apply
filament power.

Best,

-John

===============


> 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
>
>
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