Here are a few before/after pictures of one I did a while back. You can use the search here to find the thread. There are a couple of websites you can find with Google.com that might have your board. Mine was different, but not too much trouble figuring out what needs to be done.
The SCR I used was 2n5064, but anything close should work. The neon lamp triggers the SCR. My boards have a charge switch, had to jumper it. Clipped the trigger wires, and pulled the attached battery holder and replaced with wires.
One bummer is that it's pretty stubburn about input voltage, 1.5 volt battery. Tried to measure the current draw, but wouldn't flash hooked through the meter. Starts at about 75 mA, and counts down slow.
The strobe rate is about every 8 seconds, more of a flasher. Might speed it up with a smaller value capacitor, but I have nothing in that voltage range (that I know of...).