I too picked up a Special Force machine about 1 month ago. Hoping someone could help. Sporadically, the machine will award rockets in sequence without hitting the targets. Often it will reward a letter each time the right flipper is engaged. I checked under the playfield and O switch was missing a capacitor and C switch had a broken one. Put new ones on but didn't help. Would I be wrong next to look at the diodes on each letter? The really perplexing issue is why would all six be faulty? Not sure how switch matrix is setup on this machine?