Overhaul of common faults of car audio
1. Fault phenomenon: No sound when receiving FM reception of Hongle HL509 advanced car audio.
Analysis and maintenance: As the AM band reception is normal, it indicates that the shared power supply part is normal. The fault is in all levels of the FM receiving circuit. Among them, the pin ⑨ of IC101 (TA8122AN) is the output terminal of the AM detection or FM frequency discrimination signal. Therefore, the fault should be in the pre-stage signal processing of IC101 pin ⑨, such as FM mid-amp, FM local oscillator, FM high-amp circuit. When the screwdriver touches the input terminal of the frequency modulation signal input of IC101 pin ⑥, the interference noise from the horn is weak, and the input and output pins of the filter CF201 are short-circuited with tweezers. As a result, the sound returns to normal. The test shed works normally after replacing CF201, and the fault jjH.
2. Failure phenomenon: Hongle HL509 advanced car audio FM / AM band can not be converted between each other.
Analysis and maintenance: The specific manifestation of the fault is that when the band switch is switched to the AM receiving state, the FM band program is still received to 4. According to the investigation, the pin ⑧ of IC101 is the input terminal of the AM / FM band switching control signal, and its voltage is measured as the FM receiving voltage of about 3v south, and it should be about 7v of the amplitude receiving voltage when normal. It is suspected that the internal contacts of the band wind switch are bad. After repeated cleaning with alcohol, the test machine works normally and the fault is eliminated.
As LCD display in YFJ company that we usually use it to military grade battery ,especially Lithium-ion batteries ,for these battery applications ,we have obvious advantage is that we focus more on shor circuit protection which we follow the US military standard.
Short circuit protection:The following test shall be performed. Charge batteriesas specified in ; use of 4.6.3 is permitted. Measure and record the OCV. Short each battery across all the positive and negative terminals with a total external resistance not greater than 50 milliohms. After one hour remove the short from across the terminals. Measure and record the OCV. Stabilize batteries at the normal conditions of 4.3.1 for not less than 2 hours. Chargebatteries in accordance with 4.6; use of 4.6.3 is permitted. Stabilize batteries at normal conditions for not less than 2 hours, then discharge the battery in accordance with 4.7.2.3. The battery shall meet the requirements of 3.7.2.3.
Li-Ion Battery With Lcd Display
Charge voltage: 16.8V
Nominal voltage : 14.8V (4S7P)
Initial impedance : 120mΩ
Nominal capacity: 19.6Ah
Minimum capacity: 19.4Ah
Communication methods : SMBUS data communication
Electricity quantity show: LCD Electricity quantity show
Charge current: Standard Charging::0.2C5A (3.9A)
Rapid charge: 0.5C5A C(9.8A) Max
Standard Charging method : 3.9A(0.2C5A) CC(constant current)charge to 16.8V,then CV(constant voltage 16.8V)charge till charge current decline to ≤196mA(≈0.01C5A)
Charging time:Standard Charging: 6.5hours(Ref.)
Rapid charge: 3.5 hours(Ref.)
Max.discharge current: 9.8A(0.5C5A)
Discharge cut-off voltage: 10.0V
Cycle life (0.2C5A/0.2C5A) : 500 items,≧80%DOD; 300 times,≧80%DOD
Operating temperature : Charging: 0℃~45℃
Discharging:-20℃~+60℃
Li-ion Battery With LCD Display
Li-Ion Battery With Lcd Display,Battery Charger With Lcd Display,Battery Pack With Lcd Display,Rechargeable Battery Pack With Lcd Display
YFJ TECHNOLOGY (HK) CO.,LIMITED , http://www.yfjpower.com