# SDR COZA20180920123

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: September 17, 2018
- Submitted: September 20, 2018
- Operation: Air carrier
- Aircraft: [N733KA](https://openairdocs.org/aircraft/N733KA), registered now
- Make and model: Boeing 737-86N
- Registry model: [Boeing 737-86N](https://openairdocs.org/model/boeing-737-86n) (OpenAirDocs)
- Aircraft serial: 28643
- Aircraft time: 45,580 hours, 23,818 cycles
- System (JASC): [4940 · APU Start/Ignition System](https://openairdocs.org/jasc/4940)
- Part: Converter
- Part number: 1152466250
- Part serial: 1152466019999
- Condition: Intermittent
- Location: E&E Bay
- Stage of operation: IN
- How discovered: O
- Nature of condition: J
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/COZA20180920123

## Discrepancy

APU INTERMITTENTLY DOES NOT START ON BATTERY POWER. PERFORMED AN APU BITE CHECK FOR CURRENT FAULTS. FOUND MAINTENANCE MESSAGE 49-41248. TROUBLESHOT THE SYSTEM DOWN TO THE START CONVERTER UNIT USING THE FAULT ISOLATION MANUAL. REPLACED THE START CONVERTER AND OPERATIONAL CHECK NORMAL.

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