[JMS] 90281 power supply

[Brian Harris]

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