[JMS] 90281 power supply

[Don Buska - The Radio Lab Works]

Hi Brian. My #168 supply still has the removable bells on the HV 
transformer.  Mine doesn't have the HIGH/LOW switch either.  I wonder if 
your 139 and 157 supplies are also absent the HIGH/LOW switch?

Sorry can't help much on the transition when the hermetical sealed 
transformer came along, if it truly did.  There are a few with higher 
S/N's on our JMS website so we should soon know if there was a real 
transition in the 200's and above.  Naturally if we do determine such a 
transition we'll need to get a back side picture and add it to the JMS 
website as well.

73
Don N9OO

On 11/2/21 6:52 PM, Brian Harris via James_Millen_Society wrote:
> I have three 90281 power supplies with serial
> numbers 139, 157 and 237.
>
> The two earlier numbers have power transformers which have removable end bells. The later one has a larger, hermetically sealed transformer.
>
> Assuming the hermetically sealed unit is original, does anybody have a supply later with the hermetically sealed transformer?   Does anybody know when the change was made and why?
>
> I’m asking these questions because I am going to sell one of my supplies and I don’t want to sell the best version, if there is one.   If one is no better than the other, I will sell the hermetic version because doing so would leave me with a spare supply with the correct transformer and, more important, one which could easily be rewound if I should have a failure.
>
> Thanks for your time.
>
> Brian Harris WA5UEK
> Sent from my iPhone
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