# SDR CA050308013

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: March 7, 2005
- Submitted: April 1, 2005
- Operation: General aviation
- Make and model: Cessna 172S
- Registry model: [Cessna 172S](https://openairdocs.org/model/cessna-172s) (OpenAirDocs)
- Aircraft time: 2,237 hours
- Engine: Lyc IO360L2A
- System (JASC): [2432 · Battery/Charger System](https://openairdocs.org/jasc/2432)
- Part: Contactor
- Part number: X610007
- Condition: Failed
- Location: Alternator
- Stage of operation: TX
- How discovered: O
- Nature of condition: H
- Precautionary procedure: D
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/CA050308013

## Discrepancy

(CAN) ALT CHARGING SYS WOULDN`T COME ONLINE. TROUBLESHOOTING SHOWED EVERYTHING SHOULD BE WORKING.  ALL VOLTS ( IAW MM) APPEARED TO BE NORMAL, CHARGING SYS SHOWING A DISCHARGE. ALT CONTACTOR IS IN SERIES WITH MAIN BUSS & BATTERY. CURRENT NOT FLOWING THROUGH CONTACTOR, ALT FAILED TESTS.  HIGH RIPPLE VOLTS DETECTED & FAILURE OF ALT OCCURED. INSTALLED NEW ALT & CONTACTOR VOLTAGE, NO CURRENT.  SHUTDOWN SYS. VOLT CHKD AT OUTPUT SIDE OF ALT CONTACTOR & FOUND NORMAL. NO CURRENT FLOW.  REPLACED ALT CONTACTOR & SYS BEGAN TO OPS CHK OK. 2ND CONTACTOR FAILURE, TOOK 1ST FAILURE, SPLIT OPEN CONTACTOR. CONTACT POINTS DISCOLOURED & CONTACT POINTS BLACK (CARBON BUILD UP) POSSIBLE CURRENT LOAD THROUGH CONTACTOR TOO HIGH.

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