Christmas In Kent

How I made Chaser Strobes

DISCLAIMER: Do this at your own risk. I do not recommend or
advise that you use this procedure. I only admit that I do.
Strobes use high voltage and can store those high voltages even after
you unplug them.


In the credit where credit is due department, I dedicate this project to Terry Dyke and his
Grinch Detector that gave me the inspiration to do this.

I started with a curtain strobe after I tested it to be sure it was in working order:

Curtain Strobe

Then I opened it up (carefully) by removing the two Phillips screws next to the base. Be careful not to touch the circuit board because there may still be a charge in the capacitor.

Take a small insulated screw driver and short out the large capacitor indicated below with the red arrows.

You will probably see/hear a spark.

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Strobe showing capacitor discharge

Next we'll remove the small SCR in the lower corner indicated by the arrow:

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Strobe SCR removal

Here is a picture of the back side of the circuit board showing the three leads for the SCR:

I used de-solder wick to remove the solder from the three legs of the SCR. You could use a solder sucker or even cut the legs of the SCR, heat up the solder and pull the leads out. I used solder wick because it leaves a nice clean hole and since we will be soldering wire leads back in these holes I wanted the holes open for the wires.

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Strobe desolder wick with SCR

Circuit board with the SCR removed (three holes). The SCR is below left.

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Strobe with SCR removed

Next I soldered two 6" wires (about 20 gauge) into the two outside holes:

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Strobe with leads

Next I solder the two leads in the outside holes and then I solder bridge (connect) the right hole and the center hole. If the wire is long enough you can bend it over and solder it to both solder traces.
 So now one wire in connected to the left hole and the other wire is connected to the right hole and the center hole.

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Strobe with wires soldered

Now I usually test the strobe but that means screwing the base into a C9 socket and plugging it in.
Do I need to say be careful because the circuit board is exposed?
With power applied, the strobe will just sit there but touch those two wires together and zap, it flashes each time you touch the wires together.

Now before you touch the circuit board again you better discharge the capacitor.

Next we can put the strobe back together. First we'll drill a small hole in the bottom to run
the "trigger" wires through. Test fit the board back in the base before drilling the hole
so can see how the board fits in. You'll see that depending on how you slide the board
in that it may interfere with the cover and the legs that need to go along side the board.

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Strobe with trigger wires in base

Next picture is the strobe all closed up. You may want to take a moment and seal the indicated areas (arrows) with silicon or hot glue. I sealed around the screw base with hot glue.
You can seal the screws back up and the seal around the lens. Most folks just leave
as is and drill a couple of holes in the lens near the top. Since the strobe has tendency
to hang down this will tend to drain any water or condensation. I have tried everything
to seal these up but some of them still sweat and collect water. The good news
is that even if they get wet and stop working, just open them up and dry them out
and they usually start up again.

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Modified Strobe with trigger leads

OK the first strobe is modified. Think about how many of these you want to chase.
I'll be doing at least ten so I'll continue this How To once I have ten modified....

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Here's the LED chaser board I used for my proto chaser circuit.
You can get one from All Electronics.
I plan replacing the 9 volt battery with a 9 volt wall wart here.
As you can see an very simple circuit and one that I could duplicate
(if the kits weren't so inexpensive)

I built a second LED chaser kit and left out the  LED's. I ran jumpers wires for the where the LED's are connected on the board to a small perf board where I had installed ten 6 pin IC sockets.

Unfortunately I forgot to take a picture before I mounted it a small box here:

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You can see the 6 pin Opto's mounted in their sockets (four white ones on the right side). I used a few Opto's I had left over from a D-Light build. The Opto's are basically an electronic
switch. They had a diode between pin one and two (pin three is unused) and the contacts are on pin 4 and pin 6 (pin 5 unused). So I basically just replaced the LED's with the diode part of an Opto.

Here you can see the LED chaser kit under the perf board:

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You'll notice that only one lead is coming from each spot where there
used to be a LED (except the far left). That's because the chaser board uses a common
cathode. Look close in the upper left under my thumb and you'll see a little diagram
of an LED that I drew on the board to remind me.

Here's the back side of the perf board where I soldered up all the 6 pin sockets and
wires running to the LED chaser board.

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There are 10 sets or wires running out the side to be connected to the strobes.

Here's the test box I built (out of coro) to hold ten strobes. I used the vampire type C9
sockets on SPT2 wire. The strobes are all powered off the same cord.

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Now I plug in the strobes and hook up the 9 volt battery and zap X 10! I can control the rate by adjusting the variable resister on the LED chaser board. This particular LED chaser circuit has a peculiar way of starting on the third LED when you apply power to the circuit. To get around this so the strobes start on #1 I wire strobe # 1 to LED number #4. There is a bit of delay but this isn't a circuit that would keep time to music (unless : read below)

I used the same connectors here that I used when I built my MR16 spot light holder. I have a bunch of extension cords (low voltage 12v)built that use these connector so I can space the strobes apart rather than right next to one another during this test. Now I don't know how far the effective length of the trigger wires can be but I plan on keeping then relatively close to the controller.

I am also planning on a light controller (LOR or D-Light) interface using small relays
I picked up on Ebay.

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