[Amps] AL-1200 Current Limit Relay Noise

[Tom W8JI]

> parts list says DC DPST 30amp for RLY3. List could be
> in error. Will check it out tonite.

I thought you said it was the step start relay, if so it is 
AC. It is also a SPST.

If it is simply the power line switching relay it is indeed 
a DC relay DPDT 30A.

I don't know the relay number designator by heart, but a 
transformer lead connects to the DPDT DC 12V coil relay. It 
is on the outer edge near the terminal strip and held by two 
screws. The only way that relay hums is from a bad LV supply 
electrolytic, but that would be rare.

 The other one is AC and does the step start with a resistor 
near it and it is located about midway on the panel. That is 
the relay that commonly hums.

Be sure you know which relay is actually doing the humming!

73 Tom