Just to add my 2-cents...had the same issue - got a moment today to look at it....the quad opto board (underneath the playfield) was pristine - just re-seated the connectors since I was staring at them....the opto's at the top of the ramp - for me - I don't see how you can realistically perform any alignment - the opto's sit within a plastic socket...so I simply loosened both TX and RX boards cleaned the opto's with alcohol and re-flowed the 4 solder pads on each board....(to me that was the root problem).....put it all back together and everything was copacetic....