[Amps] sb-1000

[Gudguyham at aol.com]

In a message dated 2/13/04 01:58:27 AM Eastern Standard Time, kb1gfv at arrl.net 
writes:


> I am about to re-wire my sb-1000 for 240 volt operation.  I am confused 
> by the schematic that I found at www.g0ngg.co.uk  The schematic shows 
> the fan wires (purple) wired to terminals 3 and 5 on the barrier strip.  
> On my amp they are wired to 3 and 4.  For 120 volts this is equivalent.
> 
> Looking at the schematic for 240 volt operation, I don't understand how 
> the fan would operate with the specified connection (terminals 3 and 5) 
> (this is question number 1).  Question number two, if the answer to 
> question one is it won't operate, how do I wire the fan ( I assume that 
> the single jumper between 3 and 4 will be required)?
> 
> Thanks for the help.
> 73 Tim W1WCI
> 
> _______________________________________________
> 

TIM, the 120volts for the fan when the amp is plugged in for 240v operation 
is derived from one leg of the 120 from the wall socket and the neutral is 
derived from the center tap of the dual primary plate transformer.  So wire up the 
fan in the 240 operation mode as it is shown in the manual or wherever you 
saw it such that one leg of the fan sees one hot leg of the 240 (which is 120) 
and the other leg of the fan sees the center tap connection of the dual primary 
transformer, the fan will work just fine!
Good Luck