Sign Cabinet LED Retrofit Guide
Step-by-step fluorescent to LED retrofit using TMT Midi modules and Midi Stick system.
Fluorescent to LED in Four Phases
Phase 1: Assessment
Measure the cabinet (length, height, depth), record the existing lamp count and type, inspect the face material and diffusion, and identify the supply circuit feeding the sign. Note whether the cabinet is single or double-sided.
Phase 2: Planning
Match the existing light output using the Lumen Tables for Midi 4 (24V) or Midi 3 (12V). Lay out Midi Stick rows, then size power supplies using the official per-model load limits (e.g., 32 Midi 4 at 1.7W or 34 Midi 3 per 60W/12V Class 2 circuit).
Phase 3: Installation
De-energize the sign. Line-voltage work — removing ballasts and lamp sockets and wiring supply inputs — must be performed by a qualified electrician per local code. Cut Midi Sticks to length, snap in modules, mount the rows, and wire the low-voltage Class 2 circuits.
Phase 4: Verification
Power up and check face illumination for evenness and hot spots at night or in shade. Confirm each Class 2 circuit is within its load limit, label the supplies, and document the install for the warranty record.
Frequently Asked Questions
Can I reuse the existing fluorescent wiring?
The line-voltage feed to the sign is typically reused, but ballasts and lamp sockets are removed or completely bypassed. The LED power supplies connect to the line-voltage feed, and modules run on new low-voltage Class 2 wiring. Line-voltage work must be done by a qualified electrician per local code.
How do I match the brightness of the old lamps?
Use the published Lumen Tables for Midi 4 (24V) and Midi 3 (12V) to select the module, row count, and spacing that meets or exceeds the existing output for your cabinet size, single or double-sided.
Can double-sided cabinets be retrofitted?
Yes. The Midi Stick system supports single and double-sided cabinets, and the lumen tables provide separate reference values for each configuration.
How many power supplies will the retrofit need?
Total the module wattage from your layout and apply the official TMT per-model load limits per 60W/12V Class 2 circuit. Multi-circuit supplies like the 240W LDM240P-12-C24 (four independent 5A circuits) reduce supply count on large cabinets. The ROI Calculator automates the estimate.