Lamp Received Power But Failed to Strike

Common Symptoms

• Tower raises, engine runs, but one or more lamps stay dark after warm-up period
• Controller LCD shows fault code 9 or Lamp No-Strike on the display
• Lamp flickers briefly then shuts off without fully striking
• Remaining lamps on the fixture may stay lit while one head is dark
• Fault light or alarm indicator on the operator panel comes on
• Engine continues to run normally at rated RPM despite the lamp fault
• Re-starting the unit cycles the lamp again but it still fails to light

Probable Causes (Ranked by Likelihood)

• Metal halide bulb is end-of-life or burned out internally Very Likely
• Bulb socket corrosion or loose socket contact preventing proper current flow Very Likely
• Ignitor module failed and is not producing the high-voltage strike pulse Likely
• Ballast failure causing low or no output voltage to the lamp Likely
• Wiring damage or loose connection between ballast, ignitor, and lamp head Possible
• Lamp recently replaced but bulb not fully seated in socket Possible
• Capacitor in the ballast circuit failed, reducing ignition voltage Less Likely

Step-by-Step Diagnostic Procedure

1. Step 1. Clear the fault and attempt a manual re-strike. Press STOP, wait 10-15 minutes for the lamp to cool completely, then restart in MANUAL or AUTO. Metal halide lamps will not re-strike hot. If it lights after a cool-down, the bulb may be marginal but not yet fully failed.

2. Step 2. Inspect the bulb visually. Remove power first. Look for blackening at the arc tube ends, a broken or collapsed arc tube inside the outer envelope, or a cracked outer glass. Any of these means the bulb is done. Replace it with the correct wattage and base type listed on the lamp head nameplate.

3. Step 3. Check the socket contacts. With power off, look into the lamp socket for greenish corrosion, carbon tracking, or deformed spring contacts. Clean corrosion with electrical contact cleaner and a small wire brush. A burnt or melted socket must be replaced.

4. Step 4. Check for loose or damaged wiring between the ballast enclosure and the lamp head. Tug gently on each connector. Look for chafed insulation, melted wire jacketing, or terminals that have backed out of their housings. Repair or replace damaged sections.

5. Step 5. Test ballast output voltage with a multimeter set to AC. With the system running and the lamp removed, measure AC voltage at the socket terminals. Consult the ballast label for rated open-circuit output, typically 300-450V AC depending on wattage. If voltage is zero or well below spec, the ballast or capacitor has likely failed. This step involves high voltage. Use appropriate caution.

6. Step 6. Check the ignitor. The ignitor produces a high-voltage pulse (2,000-4,000V spike) to start the arc. You cannot test this safely without specialty high-voltage test equipment. If the ballast voltage is present but the lamp will not strike with a known-good new bulb installed, the ignitor is the most probable next failure. Replace the ignitor and retest.

7. Step 7. If replacing the bulb, ignitor, and verifying wiring does not clear the fault, the ballast itself needs bench testing or replacement. Ballast replacement is a straightforward swap but confirm replacement is rated for the same lamp wattage and voltage as the original unit nameplate. If the fault persists after a confirmed correct ballast swap, escalate to a Magnum service dealer to check the controller lamp-circuit sensing board.

Frequently Asked Questions