Years ago when I first got into the hobby,  and being pretty green around pinballs, I called on a local tech to come fix the flippers on my GnR..  I watched him poke and probe, scratch his head,  umm and argh..  20 minutes later he had repaired it.  $160 please.!  I saw what he did,  he replaced a couple of fuses under the playfield.. 

Once bitten...