Design available to download on Cults3d -Click Here
 
After years of iterative revisions—and finally getting hands-on with real aircraft annunciators—I’ve created a faithful, maker‑friendly CAD of the 433 Korry used for Master Caution, Fire Warning, and STAB OUT OF TRIM indications. This version is purpose-built for the 737SS project using real-world dimensions and clearances while remaining adaptable for other home cockpits and sim builds.
What you’re buying: Digital CAD files only (no electronics, hardware, or printed parts).
Lenses: Available separately for a professional finish:
https://www.737diysim.com/product-page/737-master-caution-fire-warning-stab-out-of-trim-annunciators-lenses
 
What Makes It Essential
Authenticity through access: The geometry was dialed in only after I acquired real annunciators—this delivers accurate lens proportions and a realistic “press” action feel in a DIY-friendly package.
Built for makers: Optimized for 3D printing and easy assembly with a 3‑part printed construction (+ recommended PCB as a 4th component). The design accepts 2 LEDs and provides a press-to-acknowledge activation feel using tactile components.

Flexible & customizable: Provided as CAD so you can adapt dimensions, wall thicknesses, standoffs, or fitments to your sim’s constraints. Perfect if you want to integrate your own electronics or mounting strategies.
Finish like the real thing: Lenses are the exact dimensions of the Boeing Korry units for an authentic look; the outer case is slightly larger to suit plastic 3D printing (instead of metal housings).
 
Intended Use & Context
Primary use: 737 flight simulator annunciation for Master Caution, Fire Warning, and Stab Out of Trim.
Fitment context: Designed around 737SS real-world panel cutouts.
Note: These are smaller than the common 23 mm × 23 mm “dual‑seat” aftermarket units (e.g., CockpitSimParts). If you already have panels cut for 23×23 blocks, adjust the CAD or the panel apertures accordingly.
Electronics: Intended for tactile activation with 2 LEDs on a dedicated PCB (recommended add‑on). Link your preferred PCB here: https://www.737diysim.com/product-page/737-master-caution-fire-warning-amp-stab-out-of-trim-annunciators-pcb
What’s Included (Digital Download)
Native CAD files for the 433 Korry annunciator set
3 printed parts:
Front housing/body
Internal carrier/LED module support
Rear cap/retainer
Assembly reference diagrams (in-model) to guide orientation and stack-up
Basic spec notes for LEDs and tactile action
Recommended 4th part (sold separately): PCB designed for tactile switch + dual LEDs for a clean, serviceable installation. Add your shop URL here.
 
Key Features
Dual LED support: Split illumination or redundancy, as per your wiring approach
Tactile press action: Gives an authentic acknowledge/press feel
Lens-ready: Sized for real Korry lens dimensions—pairs perfectly with the premium lenses listed above
Maker-tuned geometry: Slightly upsized housing thicknesses for 3D-printed strength and durability
Customizable CAD: Modify pockets, posts, wire channels, or clearances to suit your harness and mounting method
Dimensions & Fit Notes
Lens: Matches real Boeing Korry geometry
Outer housing: Slightly larger than metal originals to suit 3D printing
Printing & Materials (Recommendations)
Material: PLA or PETG for ease; ABS/ASA if you need added heat resistance
Wall thickness: 1.6–2.0 mm minimum for strength (housing)
Layer height: 0.12–0.20 mm for crisp edges and a clean lens seat
Orientation: Print main body to keep lens opening crisp and square; minimize supports inside light paths
Light management: Consider darker material or internal paint to eliminate light bleed; optionally add internal baffles or thin foil
Electronics & Assembly (General Guidance)
LEDs: 2× standard 3 mm or 5 mm (depending on your chosen PCB layout)
Switching: Tactile switch integrated on the recommended PCB
Wiring: Route through the rear; strain-relieve where possible
Press feel: Adjust tactile switch travel/height via PCB choice or shim for your preferred feel
Note: Exact PCB, LED spec, and wiring are builder‑selectable. This listing provides the mechanical CAD and mounting envelope—not a full electronics kit.
Limitations & Important Notes
Digital files only: No printed parts, electronics, fasteners, or wiring included
Footprint: Smaller than 23×23 mm aftermarket blocks; verify your cutouts
DIY variability: Tolerances can differ across printers and materials—test print and fine‑tune as needed
Press action: Character depends on your tactile switch/PCB choice
 
Suggested Use With
Premium Lenses (exact Korry size):
https://www.737diysim.com/product-page/737-master-caution-fire-warning-stab-out-of-trim-annunciators-lenses
Dedicated PCB (strongly recommended):
https://www.737diysim.com/product-page/737-master-caution-fire-warning-amp-stab-out-of-trim-annunciators-pcb
 
License & Usage
Default: Personal Use – non‑commercial (no resale of files or derivatives; no sale of printed parts).
 
Quick FAQ
Does this include the lenses?
No. Lenses are available separately (link above).
Does this include electronics?
No. You’ll supply LEDs, switch, and wiring. A dedicated PCB is recommended.
Will this fit 23×23 mm aftermarket cutouts?
Not directly—this is designed to 737SS geometry. Modify the CAD or your panel as needed.
Can I modify the files?
Yes—this is why CAD is provided. Please respect the license terms.
3D printing settings
Build/Parts/Print guide:
https://www.737diysim.com/build-guides-1/737ss-master-caution-%26-fire-warning-korry