# SDR ASAA2016112218811

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: November 22, 2016
- Submitted: November 28, 2016
- Operation: Air carrier
- Aircraft: [N518AS](https://openairdocs.org/aircraft/N518AS), registered now
- Make and model: Boeing 737890
- Aircraft serial: 35693
- Aircraft time: 30,161 hours, 8,934 cycles
- System (JASC): [2420 · AC Generation System](https://openairdocs.org/jasc/2420)
- Part: Circuit Breaker
- Part number: 11519681
- Condition: Failed
- Location: Ee Bay
- Stage of operation: TX
- How discovered: O
- Nature of condition: J
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2016112218811

## Discrepancy

DURING PDC FOUND NR 1  TRANSFER BUS OFF LIGHT ON. NO POWER TO NR 1 BUSS.  ACFT GROUNDED. PERFORMED TRANSFER BUSS OFF LIGHT ILLUMINATES FAULT ISOLATION IAW FIM 24-21 TASK 822. FOUND BTB FAULT ON NR 1 GEN CONTROL UNIT. PERFORMED BTB FAULT ISOLATION IAW FIM 24-21 TASK 810. REMOVED AND REPLACED BTB1, C804 IAW AMM 24-21-41. OPS CHECKS GOOD. GROUND VERIFICATION SATISFACTORY.

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