In the past,I referenced a product I used called Nickel Print,that I used on a broken printed circuit board.This is for short small cracks or fractures in the circuit itself,and not really recommended for large wide open gaps.It's highly conductive & fast drying too.
Here's a link to it,and I highly recommend it,if you can't find a replacement for your printed circuit board.
It works very well,and has stood the test of time for me so far.
http://www.alliedelec.com/search/productdetail.aspx?SKU=6610385