Flipper coil diodes must be fitted the right way
Each flipper coil carries 1N4004 diodes to absorb the turn-off spike; without them the game can behave oddly or be damaged. The bands must face the correct lugs, with the brown power wire on the outer lug at the banded end of the diode.
Systems
Related tips
- Check a flipper coil for heat damage by its sleeve
- Both right flippers dead, left works: wire at a coil lug not making contact
- One flipper dead with full voltage at the coil: cracked joints at the flipper relay
- Right flipper still dead after fitting a new coil: bad EOS switch
- Replacing a flipper coil
- Right flipper dead though coil and switches test fine: cracked joint on a backbox board
- Upper flipper flutters, then dies: pitted EOS contacts
- Both right flippers dead with power present: dirty cabinet button contacts
Source: Repairing Bally Electronic Pinball Games from 1977 to 1985, Part Three, Clay Harrell (pinrepair.com)