How do I start Maintenance Protocol in CONTROL Resonant?

Finish The Hedron Link, complete Zoe’s Briefing at the Central Watchtower, then track Maintenance Protocol to the Deepest Underpass Oldest House door.

What is the reward for Maintenance Protocol?

The Standard Issue Coverall outfit after fixing the three Underpass bulbs and choosing Break the bulb in the projector slide.

CONTROL Resonant Maintenance Protocol

Prerequisite: Finish Zoe’s Briefing first — this quest starts from that Watchtower conversation.

Quick answer: CONTROL Resonant Maintenance Protocol starts from Zoe’s Briefing (after The Hedron Link → talk to Zoe at the Central Watchtower). Fix three temperamental Underpass bulbs (Volatile, Electrosensitive, Botanophobic), return to the projector, then Break the bulb inside the slide. Reward: Standard Issue Coverall outfit. Unofficial companion.

How to start

Finish The Hedron Link.
Complete Zoe’s Briefing at the Watchtower (radio call → talk to Zoe).
Maintenance Protocol appears in Side Stories — also opens / pairs with New Growth if not already active.

Deepest Underpass → Oldest House door

Fast travel to Deepest Underpass.
Climb the south ledge to the Oldest House door; inspect / talk (Zoe on intercom).
Keypad Morse for “in” — guides report dot-dot-dash (two short, one long).
Clear Mold in the first room → projector room → watch the maintenance film.
Switchboard console marks the three bulb locations on the map.

Fix all three bulbs (any order)

Bulb	Where (typical)	How to calm / clear
Volatile	Near Halfway Trail	Reassure with calm dialogue, clear the Hiss wave, then twist / fix (“You deserve to be fixed” class lines).
Electrosensitive	Near / under Research Site power	Drain or remove nearby charged power cores / batteries so the bulb is not stressed, then fix.
Botanophobic	Island north of Research Site	Destroy Mold / explosive growth around the bulb, then fix.

Exact dialogue strings can vary slightly by localization — pick the calming / “fix” options, not the aggressive ones. Twist interactions are often “righty-tighty” three times per the film.

Projector finale

Return to the projector room, interact with the bulb in the film, enter the slide space, then choose dialogue culminating in Break the bulb to escape and close the quest. Outfit reward: Standard Issue Coverall.

Related: New Growth · Missions · Underpass / Recursions