>I have an Ameritron AL-80A which makes the loud CLUNK sound when the
>power switch is engaged. I assume that step-start/current inrush
>protection would prevent this. My questions for the list:
>
>1. What type of step-start do you suggest for the AL-80A? Your ideas
>are welcome.
>
>2. I ran across a step-start circuit for the Heath SB-1000 (which I
>believe is a clone of the AL-80A) in the June 1996 QST (Hints & Kinks,
>page 69) designed by W3IRZ. He uses a large 25-watt resistor (for
>240-volt operation) and a DPDT relay with a 120-VAC coil. Has any one
>tried this?
AC coil relays tend to buzz.
> Has any one improved the circuit? This looks pretty simple
>even for me and the parts seem to be readily available.
>
The circuit shown in Figure 1 at:
www.vcnet.com/measures
is simple, uses a pair of inrush resistors so that it works on 120v and
240v, and can be powered by the AL-80's 12vdc (?) supply. The timing
element is the hv supply filter capacitors. When the caps. are 2/3
charged, the relay closes. For an AL-80 a pair of 7w c. 25 ohm resistors
should work satisfactorily.
later, Jack
cheers
Rich...
R. L. Measures, 805-386-3734, AG6K
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