Need help finding a trigger of older radio

[Jeff@Redline]

I have a JR PROPO Alpina pcm radio for a little boat that I bought. It looks brand new but it's missing the trigger. Does anyone know where I could get a trigger to fit this?

I know this is an old radio, but I would rather not have to buy a new radio just because the trigger is M.I.A!!

Thanks for the help.