Old amp with new source

Getting back on the bench a bit after a while.  After tidying up, thought I would try fishing out the "Mighty Mike" amp I build a few years back out of the box and try it with the Si5351.  After putting on a new heat sink and soldering back on a cap that had come off, I hooked it up.  Wasn't getting anything at first and not sure why.  Went through hunting for shorts/opens and didn't find any.  But after doing that, tried again and it worked.  I'm getting 1w with 12v supply and 2w with 15v supply.