After fitting a new replacement clock opto board, fuse F116 blows three to five seconds after power-on, during the start-up screen. It only happens with one particular clock connector plugged in.

F116 blows a few seconds after power-up with a new clock board: uncut header pins

Cause: Four header pins on the new board that should have been cut off during manufacture had been left in place, shorting the 12 V supply on that connector.

Checks

• Plug the clock connectors in one at a time to find which one blows the fuse.
• Compare the new board's headers with the original or the maker's instructions for pins that should be removed, and check the harness for a pinched or cut wire behind the clock.
• Never fit a larger fuse to test: it only lets the short do more damage.

Fix

• Clip off the header pins that should not be there (check with the board's maker first), then refit the clock.

Systems

• WPC Fliptronics

Games

• Twilight Zone

Related tips

• Display goes dead after fitting a new clock board: check fuse F116
• Check opto power supply message with good fuses: reseat the opto board plug
• Fuse F116 keeps blowing
• Burned power driver board traces at the header feeding AC to the Fliptronic board
• Main cabinet fuse blows instantly after a power surge: shorted varistor
• WPC: fuse holder snaps off the power driver board: replace the clips properly
• Find what is blowing a fuse
• Test every fuse properly before first power-on

Source: Pinball Repair help group!! (Facebook group)