Fred,

I do have a 20 amp and a 35 amp in the shack.   The 20 amp has 12 fins 
on the rear heat sink and 2 transistors mounted in the gaps between the 
fins.

The 30 amp has 24 fins and 4 transistors  in the gaps between the fins.

There might be a better way to tell, but hope this helps.

73, Steve KW3A

On 2/22/2011 2:31 PM, Fred Adams wrote:
> I recently picked up a large Astron power supply but the owner had no
> paperwork on it.  Do any of you guys know if there is any way to tell the
> size?  I believe it is a 30 or 35 amp supply but I do not know for sure.
> Thanks much,
>
>
>
> Best wishes,
>
>
> FRED C. ADAMS W4HC
> THE HOUR IS LATE AND
> THE NIGHT IS FAR SPENT
>