[Amps] (no subject)

Tom W8JI w8ji at w8ji.com
Mon Jul 9 10:39:50 EDT 2007


>I am a newbee non technical novice. I bought a SB 220 . 
>Changed the wiring according to the manual from 110 to 240. 
>Plugged linear into a mfj soft start plug and blew a fuse 
>in mfj box.( power off on linear whole time) . Inspected 
>the linear and discovered that the interlocking spring was 
>hitting the metal spacer mounted on the feedthrough 
>insulator.?

If the power was off on the linear, as you say above, the 
fuse blowing has NOTHING to do with the interlock. You must 
have a wiring problem.

Before doing anything more measure the resistance from the 
power cord pins to the chassis of the amplifier. It should 
be infinite with the power switch off or on.

This is because all good designs do not connect any part of 
the primary circuit to the chassis.   :-)

You need to learn why the fuse blew with the amplifier off. 
This is almost certainly a wiring issue, or perhaps an 
unintentional short.

THEN, only after you fix that, it is time to worry or ask 
about other things.....like the interlock.

73 Tom 




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