Yaesu CHATNOW 75028 Series Alignment Procedure

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Testing and Alignment Procedure

CHATNOW 75028XXXX series

1. Recommended Test Equipment

1.1 HP8920A Communication Test Set

1.2 Fluke 50S Digital Thermometer

1.3 Fluke 77 Digital Voltmeter

1.4 Power Supply

1.5 Thermometer with digital display

2. Test Preparation

2.1 Connect a 6.0Vdc power source to the positive terminal input point and the

negative battery input point (GND) for negative terminal.

2.2 Connect a communication test set to the antenna test point.

2.3 Connect a 1 watt 16ohm resistor from speaker +SP to -SP.

2.4 Test point +SP should be connected to Audio In HI of the HP8920A.

2.5 Test point -SP should be connected to Audio In LO of the HP8920A.

3. Voltage Regulator Test

3.1 Connect a voltmeter to output of regulator TP11 (VCC) and measure the

voltage. The DC value must be between 3.45 to 3.58Vdc.

4. Low_Battery Detect Alignment

4.0 Connect a voltmeter to TP10(LOW_BATT).

4.1 Adjust power supply to 4.80Vdc +/- 10mV.

4.2 Select one resistor from R112 to R114 until the voltmeter reading is close to

2.25Vdc +/- 40mV. Unit will beep

5. Battery ICON Level Test

5.1 Adjust power supply to 5.4Vdc +/- 50mV.

5.2 Cycle power by turning the unit Off then On.

5.3 Check 2 segmentsof the battery level icons are solid.

5.4 Adjust power supply to 5.0Vdc +/- 50mV.

5.5 Cycle power by turning the unit Off then On.

5.6 Check 1 segment of the battery level icons are solid.

5.7 Adjust power supply to 4.3Vdc +/- 50mV.

5.8 Cycle power by tuning the unit Off then On.

5.9 Check segments of the battery level icons are shell.

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Page 1 Testing and Alignment Procedure CHATNOW 75028XXXX series 1. Recommended Test Equipment 1.1 HP8920A Communication Test Set 1.2 Fluke 50S Digital Thermometer 1.3 Fluke 77 Digital Voltmeter 1.4 Power Supply 1.5 Thermometer with digital display 2. Test Preparation 2.1 Connect a 6.0Vdc power source to the positive terminal input point and the negative battery input point (GND) for negative terminal.
Page 2 6. VCO Alignment 6.1 Set unit to Channel 1 and connect a voltmeter to TP1. 6.2 Press the PTT switch so unit is in transmit mode. Adjust L7 until the voltmeter read 0.70Vdc ±0.10Vdc. L7 is located under the VCO shield can and is accessible through the hole cut-out. Spread coils evenly.
Page 3 9.6 Check that transmit audio distortion is less than 5%. 9.7 Switch off the audio generator. 9.8 Set Filter 1 to 50Hz HPF. Set Filter 2 to 300Hz LPF. 9.9. Check the Hum and Noise 10. Accessory Test(MODE 1) 10.1 Connect an FM deviation meter (communication test set) to antenna test point.
Page 4 13.4 Reduce signal generator level until the unit squelches. The difference between generator levels for “open” vs. “squelched” should be 1-5dB. The squelch sensitivity should be between 8 to 16dB SINAD. 14. Audio output power and distortion 14.1 Increase signal generator level to -47dBm. 14.2 Set Ext Load R to 16ohm.