Left waterfall ramp magnetic sensor false-triggers on its own (vibration)

Correction: this is a MAGNETIC sensor (reed/hall switch), not an opto — disregard the opto steps in the original description. Revised fix for a magnetic sensor reading constantly closed, cheapest-first:

1. Switch test: confirm the switch reads constantly closed.
2. Check for a stray or misplaced magnet / magnetized part near the sensor. A nearby magnet holds a reed switch closed by keeping the reeds attracted together, so a magnet that has shifted or a stuck magnetized ball can pin it on. Remove or relocate it and re-test.
3. If it still reads closed with no magnet nearby, the reed contacts are likely worn or welded shut (reed switches fail closed with age/current). Replace the reed switch — they are cheap and a common failure.
4. Also inspect for a cracked/cold solder joint or a pinched/shorted wire on the switch leads, which can also present as constantly closed.
5. If it is actually a hall-effect sensor board rather than a passive reed, a failed sensor outputs a constant state — replace the sensor board.

Grounding on reed-switch behavior: Wikipedia "Reed switch" (a nearby magnet completes the circuit; contact wear/welding is the wear-out mode).

Second correction: the symptom is PHANTOM triggering — the magnetic sensor fires on its own from playfield vibration/shock — not stuck-closed. Disregard the stuck-closed steps above. Revised fix for a reed/magnetic sensor false-triggering from vibration, cheapest-first:

1. Confirm with the fist test: rap the playfield with your fist. A correctly adjusted switch should NOT register from that vibration. If this switch does, it is set too sensitive / its margin is too small.

2. Widen the actuation margin (most likely fix). The sensor is tripping on marginal proximity that vibration pushes over the threshold:
- Passive reed near a magnet: increase the gap / reposition so the reed sits farther from the switching threshold and needs a deliberate ball-driven actuation.
- If the sensor has a sensitivity potentiometer, turn it clockwise to increase the margin (makes it less sensitive).

3. Secure loose hardware. A loose reed switch, its bracket, or a nearby magnet that vibrates relative to the others will self-trigger. Tighten the mount and anything adjacent.

4. Inspect for a cracked/cold solder joint or an intermittent wire/connector on the switch leads. Vibration flexes a marginal joint and momentarily makes contact = phantom hit. Reflow the joints and reseat the connector.

5. If adjustment cannot get enough margin: boost magnet strength or switch to a latching reed; an RC filter (~10k ohm + 100nF) across the output smooths electrical spikes. A worn/aged reed (vibration shortens their life sharply) should just be replaced.

Sources: Flippers.be switch-adjustment 101 (fist test; too-sensitive switches phantom-fire from bumper vibration); electroglobal.in reed-switch vibration guide (widen margin via pot, boost magnet, RC filter, latching reed).

Resolved: reseating the connector on the magnetic sensor fixed the false-triggering. The intermittent phantom hits were a bad/loose connection at the connector, not a too-sensitive switch or dead reed. Closing as fixed.