[Hallicrafters] SR-400A PA cathode resistors

[Peter Bertini]

Replace them with metal oxide resistors. they will not shift with
age or heat.

Pete k1zjh

On 8/14/09, rbethman <rbethman at comcast.net> wrote:
> Walt,
>
> While I've never owned or operated an SR-400A, my $0.002 worth, is my
> gut telling me that you nee3d not only to replace them again, BUT to
> replace them with a HIGHER wattage version.
>
> They are apparently dissipating at a higher wattage level than what has
> been in there.
>
> It could be a design flaw - OR - the preceeding owner replaced them with
> a lower dissipation set.
>
> Bob - N0DGN
>
> Walt Cates wrote:
>> On virtually all of the 400A's I have worked on the 13 ohm resistors in
>> the cathode ckts have been discolored. They measure from 19 to 25 ohms. I
>> have always replaced them and went on. My 400A which I restored only about
>> a year ago had the same "problem" when I got it. After one year and
>> probably less than 10 hours of actual TX time the power has began to drop
>> off. I opened it today and you guessed it the 13 ohm resistors are way out
>> of tolerance again. I haven't determined if this is the cause of the power
>> drop off yet. But, I thought I would quarry the group to see if there have
>> been any changes or improvements that I haven't heard of.
>>
>> Best Regards, Walt Cates, WD0GOF,
>> http://www.myhamshack.com/WD0GOF/<http://www.myhamshack.com/WD0GOF/>
>>
>>
>
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