medieval madness catapult led mod kit

[thunder1001]

Hi,
i recently bougt a Medieval Madness.
there was a medieval madness catapult led mod kit inside from pimpmypin.com (website not online anymore)
But it was not working, and now i know why...
See picture, the opto part is missing.
Can somebody help me out on this one?

 

[drhex]

Do you have any idea how this is supposed to look like? Is it just the cable that is missing?