Overview

The Type L-828 / L-829 CCR includes five (5) factory-installed fuses. These protect the control transformer primary and secondary circuits. Fuse identification and ratings are listed in Table 2: Fuses.

F1 & F2 – Control Transformer Primary Fuses

Location: Panel-mounted fuse holder.
Function: Protect the primary side of the control transformer.
Rating: 5A Fast-Acting, 10mm x 38mm, 250V Midget Fuse.
ALC Part Number: 82-88.
What They Protect: Input power feeding the control transformer primary.
If F1 or F2 is Blown: No DCMU display, no control voltage present, no 120VAC or 15VAC secondary output, CCR appears completely dead.
Troubleshooting Steps: Verify correct input voltage matches nameplate. Measure input voltage at contactor line side. Inspect control transformer for primary short. Check for wiring damage on control transformer primary. Do not replace until root cause is identified.

F3 – 15VAC Secondary (DCMU Power Circuit)

Location: DIN rail fuse block.
Function: Protects 15VAC secondary winding of control transformer.
Rating: 5A Fast-Acting, 1/4" x 1 1/4", 250V Glass 3AG.
ALC Part Number: 82-76.
What It Powers: Digital Control & Monitoring Unit (DCMU), Firing Card logic power.
If F3 is Blown: Blank display, DCMU not powering, CCR will not operate, possible partial power symptoms.
Troubleshooting Steps: Measure control transformer secondary voltage (11–12 terminals: 14.5–16.5VAC). Inspect DCMU wiring. Inspect firing card connections. Look for shorted 15VAC control wiring.

F4 – 120VAC Secondary (Contactor Coil Circuit)

Location: DIN rail fuse block.
Function: Protects 120VAC secondary feeding contactor coil.
Rating: 2.5A Fast-Acting, 1/4" x 1 1/4", 250V Glass 3AG.
ALC Part Number: 82-77.
What It Powers: Contactor coil only.
If F4 is Blown: Display powered, CCR appears normal, contactor will not energize, CCR will not turn on (no output current).
Troubleshooting Steps: Measure 120VAC at terminals 9–10 (should be 115–130VAC). Inspect contactor coil for short or damage. Check firing card output to contactor coil. Inspect coil wiring connections.

F5 – 120VAC Internal Remote Circuit Fuse

Location: DIN rail fuse block.
Function: Protects 120VAC internally powered remote control circuit.
Rating: 1A Fast-Acting, 1/4" x 1 1/4", 250V Glass 3AG.
ALC Part Number: 82-78.
Important Note: F5 is only active in 120V Internally Powered remote configurations. The fuse block is installed even if the CCR is not configured for internal 120V remote.
If F5 is Blown: Remote control not functioning, CCR works in Local mode, remote commands not recognized.
Troubleshooting Steps: Verify remote control configuration (24V vs 120V). Confirm whether system is internally or externally powered. Inspect remote wiring (B1–B5 / B10–B100). Check for miswired external voltage source.

General Fuse Troubleshooting Guidance

Before replacing any fuse, follow Lockout/Tagout procedures. Verify absence of voltage. Identify cause of fault. Replace only with identical rating and type. Replacing with incorrect fuse type may cause repeated failure, remove protection, or damage internal components.

Airport Lighting Company | Type L-828, Type L-829 Ferroresonant Constant Current Regulator