# SDR ASAA2021080435622

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: August 4, 2021
- Submitted: November 9, 2021
- Operation: Air carrier
- Aircraft: [N594AS](https://openairdocs.org/aircraft/N594AS), registered now
- Make and model: Boeing 737890
- Aircraft serial: 35191
- Aircraft time: 47,766 hours, 14,148 cycles
- System (JASC): [2397 · Communications System Wiring](https://openairdocs.org/jasc/2397)
- Part: Coupler
- Part number: 8220987004
- Part serial: 171562
- Condition: Faulted
- Location: Hf Antenna
- Part time: 39,094 hours, 11,434 cycles
- Stage of operation: NR
- How discovered: 9
- Nature of condition: O
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2021080435622

## Discrepancy

UNABLE TO TRANSMIT ON HF #2 RADIO. NO SIDE TONE. RECEIVES FINE. GROUNDED - YES. UNABLE TO DUPLICATE OPS NORMAL. REF B737-800 AMM 23-11-00. DUE TO HISTORY AND TECH SVCS NOTE, REQUIRES PRECAUTIONARY REPLACEMENT OF #2 COUPLER. REMOVED AND REPLACED #2 HF COUPLER AND #2HF TUNES/OPS CKS NML PER B737-800 AMM 23-11-61.

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