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Uniden Washington MB8719 Alignment


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Alignment Instructions

Caution: Use isolation transformer or observe polarity when connecting test equipment. Maintain line voltage at 120V AC. Allow a 15 minute warm-up period. Adjustments made with 13.8V DC Input. Connect low sides of test equipment to gorund unless specified otherwise. Connect 50 ohm dummy load or antenna before keying transmitter.

Synthesizer

Test Equipment Transceiver Adjust Remarks
Input of freq counter to TP12 (IC2 Pin 8) CH19 AM Check for 10.240MHz
Input of oscope to TP16 (L18 Secondary) CH19 AM Clarifier Midrange L18 Adjust for maximum RF
Input of DC meter to TP9 CH10 AM L13 Adjust for 5.0V
Input of oscope to TP1 CH19 USB L14 Adjust for maximum RF
Input of freq counter to TP 1 CH19 USB Clarifier Midrange CT3 Adjust for 34.9875MHz +/- 20Hz
Input of freq counter to TP 1 CH19 LSB Clarifier Midrange L19 Adjust for 34.9825MHz +/- 20Hz
Input of freq counter to TP 1 CH19 AM Clarifier Midrange L20 Adjust for 34.9850MHz +/- 20Hz
Input of freq counter to TP 1 CH19 LSB xmit VR3 Adjust for 34.9825 +/- 20Hz
Input of freq counter to TP 10 CH1 USB Check for 1.430MHz
Input of freq counter to TP 3 CH19 USB CT1 Adjust for 7.0825MHz +5Hz or -0Hz
Input of freq counter to TP 3 CH19 LSB CT2 Adjust for 7.8975MHz
Input of freq counter to TP 3 Disconnect TP7 and TP8 CH19 AM xmit L17 Adjust for 7.8000MHz +5Hz

Receiver

Connect an AC VTVM of AF wattmeter across speaker voice coil. Adjust volume control to obtain a suitable indication/ Set generator output low enough to precent AGC limiting. Mode AM, RF Gain Maximum, Squelch Minimum, Clarifier Midrange, NB off.

Test Equipment Transceiver Adjust Remarks
Output of signal gen thru .01uF to TP13 (TR10 Collector) 7.8MHz 1KHz @ 30% modulation CH19 AM L3,L4 Adjust for maximum output
Output of signal gen thru .01uF to antenna input. 25.185MHz 1KHz @ 30% modulation CH19 AM L5,L6,L7,L8,L9,L10 Adjust for maximum output. If necessary readjust L3 and L4 for maximum
Output of signal generator thru .01uF to antenna input. 27.185MHz 1KHz @ 30% modulation. input of oscope to TP14 (TR6 Emitter) CH19 AM L1,L2 Set generator output for 10db signal to noise plus noise ration of receiver. Inject a 100pps, 1uSec pulse width signal at antenna input. switch noise blanker on and adjust for minimum amplitude pulses.
Output of signal gen thru .01uF to antenna input. 27.185MHz 1KHz @ #)% modulation. output 1000uV CH19 AM Squelch Max VR2 SQUELCH RANGE Adjust so that squelch just breaks.
Output of signal gen thru .01uF to antenna input. 27.185MHz 1KHz @ #)% modulation. output 100uV CH19 AM S/RF/MOD set to S/RF VR1 SIGNAL METER Adjust for S9 on S-Meter
Output of signal gen thru .01uF to TP13 (TR10 Collector) 7.8025MHz no modulation CH19 USB L3,L4 Adjust for maximum output.
Output of signal gen thru .01uF to antenna input. 27.186MHz no modulation CH19 USB L5,L6,L7,L8,L9,L10 Adjust for maximum output. if necessary readjust L3 and L4 for maximum

Transmitter

Connect a RF wattmeter and 50 ohm 25 watt dummy load to antenna conenctor. Be sure to check tx frequency and power on all active channels after alignment of tranmitter

Test Equipment Transceiver Adjust Remarks
Input of RF wattmeter and 50 ohm 25 watt dummy load to antenna input. Inject a two tone 50mV signal at mic input CH19 USB Mic Gain Maximum L26,L27,L28,L29,L36 Set VR7 to minimum. Adjust for maximum RF output.
Input of spectrum analyzer or harmonic meter to antenna input CH19 AM Mic Gain Minimum L39 Adjust for minimum at 54MHz (2nd Harmonic)
Input of DC meter to TP15 CH19 AM RT301 VOLTAGE REGULATOR Adjust for 13.80V
Input of oscope or modulation meter to antenna input CH19 AM S/RF/MOD meter set to MOD VR12 MOD METER Adjust so that MOD meter agrees with external modulation meter
Insert a 0-150mA DC current meter at TP8. No modulation CH19 USB Mic Gain Min VR8 RF DRIVER BIAS. Adjust for 35mA idle current. Reconnect TP8
Insert a 0-150mA DC current meter at TP7. No modulation CH19 USB Mic Gain Min VR9 RF FINAL BIAS. Adjust for 45mA idle current. Reconnect TP7
Input of RF wattmeter to 50 ohm 25 watt dummy load to antenna input, no modulation CH19 USB Mic Gain Minimum VR5 CARRIER BALANCE. Adjust for minimum RF output. Check LSB and readjust if necessary for minimun RF output.
Input of RF wattmeter to 50 ohm 25 watt dummy load to antenna input, Inject a two tone 50mV signal at mic input CH19 USB Mic Gain MAX VR7 RF ALC. Adjust for 11.8 watts PEP RF output maximum
Input of RF wattmeter to 50 ohm 25 watt dummy load to antenna input, no modulation CH19 AM Mic Gain Minimum VR6 AM POWER. Adjust for 4.0 watts RF output max
Input of RF wattmeter to 50 ohm 25 watt dummy load to antenna input,no modulation CH19 AM Mic Gain MIN. S/RF/MOD set to S/RF VR10 RF POWER METER. Adjust so that the PWR meter agrees with RF wattmeter

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