Re: {Collins} Step-start for 30L-1 - Good idea?

There are 2 fail modes for the KWM-2 switch.
Electrical and mechanical.

The small, round Oak switch has a hair like wire inside that will either
break off or burn up.
These Oak switch elements can be replaced if you can find them.

The mechanical snap-over-center assy that the Oak switch mounts on....will
break with repeated operation.
The over-center part of the switch breaks and then the Oak switch cannot be
operated....even if the switch is still good.
I doubt that any of these mechanical assys are available anywhere any more.

The relay in the 516F-2 is just not needed because it only helps with the
electrical switch does nothing for the mechanical breakage.

Just use a switched outlet and the power supply will not need any
modification....and retain its value.


David Harmon
CCA 97-535
Sperry, OK

-----Original Message-----
From: Collins [] On
Behalf Of Mark Pilant
Sent: Tuesday, November 4, 2014 4:17 PM
To: Collins List
Subject: Re: {Collins} Step-start for 30L-1 - Good idea?

 > The fix is the same for an electrical box with a switch on
> it....turn on and leave on the rig switch and control the power with the
> remote switch.

As an alternative, you could have the power switch in the rig energize a
relay which actually completes the circuit to the transformer.  (The relay
replaces the On / Off switch in the circuit.)

I have done this for my Collins 516F-2 as well as my Drake AC-3 and AC-4
supplies.  The relay has contacts rated for 10A, and only requires about
only about 10mA to energize.

Here is a web page I put together for a Drake AC-4 I rebuilt:

The circuit is very similar for the AC-3 and 516F-2.  Although the location
of the relay tucked in the 516F-2 chassis is different :-)

I'm in the process of writing this all up for a set of Collins pages for
gear I have been bringing back to life.


- Mark  N1VQW
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