Modutrak Searchlight Signals (WAS: Building BeNscale Signals)

[Sokramiketes]

I order the short bracket heads from BeNscale and then bend a 90 into the bracket to better match the offset in a Milwaukee Road signal.  To do this, grab the base of the bracket with a pair of needle nose and bend the magnet wires out of the way...

[Sokramiketes]

Then roll the signal on the work surface to bend the bracket.  I've found it best to bend the bracket a bit past 90 degrees so that it hugs the mast a little better.  The loop should be right beside the bulk of the head.

[Sokramiketes]

And now the magnet wires can be fished through the mast.  Be gentle during this step, as there is usually a sharp edge around the hole in the mast.  You don't want to nick or scrape the epoxy insulation on the magnet wire.

(Two notes on this image... since I'm doing a back-to-back signal, I've removed the small c-channel strain relief from the rear of the signal heads so they could be closer together.  It just pops off the back.  Also, rather than have two loops for mounting brackets, I've changed one bracket to straight wire so the heads can align.  Don't worry about either step unless you're doing a back-to-back signal)

[Sokramiketes]

Carefully thread the wires through and get the heads aligned on the mast.  Now we can solder the rest of the joints to lock everything in place.  You can see small applications of flux in this image.

[Sokramiketes]

The first few signals I assembled I left the magnet wire long on the bottom.  But I'm afraid the magnet wire will eventually break as we move these signals around.  So here's what I've come up with. 

BeNscale put their name on the bottom of the circuit board.  I use the letters as solder pads to transfer from magnet wire to 24ga stranded and add resistors at the same time.

Here I've soldered the magnet wires to the pads.  The uninsulated (silver) magnet wire is a common and hits the bottom of the ladder.  The full signal is live through the mounting bracket on the head, but I solder the common to the bottom anyway.  I'm using rosin core electronic solder here, not the separate flux, and I just hit it briefly to get the wires in place.  The joints will be heated through and not look cold once the resistors are soldered in place.

[Sokramiketes]

Next I put an s-bend in the resistor, clip the lead short, and tin the end.  The s-bend allows the resistor to clear the circuit board edges so the whole thing plugs into the resin base later.  Just make sure that nothing sticks beyond the footprint of the circuit board and you'll be fine.

[Sokramiketes]

With the resistor tinned, and the solder pads having solder on them already, all you need to do is place the resistor and heat the joint through. 

[Sokramiketes]

Add the remaining resistors, clip the excess magnet wire, and you're ready to add the 24ga stranded wires and a plug.

[Philip H]

Nice work.  Takes the fear factor out of the soldering.

Two questions - what's your soldering rig?
What's your work surface - theres a counter sunk star head drew that keeps making an appearance, but I can't tell if its Masonite or MDF or what teither of them is screwed to.

[Sokramiketes]

And finally some 24ga stranded, some heat shrink, and a 4-pin Molex connector so that it can plug into the signal driver board, and we're ready for some paint!

[Sokramiketes]

Nice work.  Takes the fear factor out of the soldering.

Two questions - what's your soldering rig?
What's your work surface - theres a counter sunk star head drew that keeps making an appearance, but I can't tell if its Masonite or MDF or what teither of them is screwed to.

Soldering rig is nothing fancy.  I haven't splurged on a heat controlled set up, so I'm using a small 12W iron from Weller:



The work bench is an MDF top on frames I threw together from 2x4's.  I screwed the MDF down so that as it gets dinged up it can be easily changed out.

[Ian MacMillan]

Very nice write up Mike. I have wanted to pick up some of these signals for a while and try them out and build triple target B&M signals.

[towl1996]

Yes, excellent work. I'm sure UP_Modeler would approve! 

[Sokramiketes]

Yes, excellent work. I'm sure UP_Modeler would approve! 

[John]

why not mount these on a DIP socket ???