CB Radio MAGNUM 1012 ALIGNMENT GUIDE
SUPPLY VOLTAGE: 13.8 VDC
1. PLL ALIGNMENT:
Convert the unit to Full Band (Code 3)
Align the VCO voltage to 0.34 ~ 0.4VV at CH.1 Band A, the test point is at
TP1 (Near C210 at the main PCB) adjust T201(HS) in counterclockwise
direction. Check VCO Voltage of CH. 40J at 4.2V ~ 5.0V
Alignment of Reference Oscillator Frequency:
Test point Pin #6 of the wafer connector in the Front PCB
- USB Frequency: 10.6925 MHz adjust RV304 at RX mode
- LSB Frequency: 10.6975 MHz adjust RV305 at RX mode
- AM/FM Frequency: 10.695 MHz adjust RV302 at TX mode
NOTE: Set the Squelch to minimum, RF Gain and Mic Gain to Maximim before
Proceeding to the alignment of TX and TX.
2. TRANSMITTER ALIGNMENT:
At CH. 20 Band E (Center Channel) FM or AM mode press PTT and adjust IFT (T11, T12, & L9) to maximum to attain more than 4W RF Power. Turn RV2 to increase the RF Power to Maximum. (Band E RF Power must be 3.6W and above). Check Channel 1 Band A & Channel 44 Band J for RF Power balancing and adjust L9 if necessary. Band E and J must be 3.6W and above while Band A is 2.5W and above.
Check AM/FM RF Power Low(Press FUNC + MODE H/L) : 0.5W~1.5W.
- Modulation Alignment for AM: 80% to 95% Adjust RV5
- Deviation Alignment for FM: 1.6 - 2.6 KHz adjust RV306
- Audio input for deviation / modulation alignment is 1 KHz, 30mv AC.
- Meter Sensitivity Alignment: AM/FM -Full Bars at RF Power High. :1 – 3 at RF Power Low.
RF Frequency Tolerance:
- AM/FM ± 400Hz Adjust RV302
- USB/LSB ± 200Hz Adjust RV301
Note: RF Low Power is applicable only in AM and FM Mode
Steps 2 SSB Checking:
SSB RF Power: 3.6W and above at Band E and J, 2.5W at Band A
Carrier Suppression: USB & LSB (Mic gain minimum)
-35dB adjust RV11
SSB Meter Sensitivity: Full Bars, Adjust RV3
RV8 is ALC and we tune it at maximum.
3. RX ALIGNMENT
Tune to Channel 20 Band E(Center Channel) AM Mode and adjust IFT L27,L25,T4 and T5 until reach the maximum usable sensitivity at 6dBuVEMF.
Adjust FM sinusoidal wave to maximum at 66dBuVEMF adjust IFT T9 and check the distortion.
Check the signal to noise ratio in FM at 0dBuVEMF, it must be 10dB and below
Check the SSB sensitivity, it must have a voltage at least 0.8VAC at -4dBuVEMF. Tune the clarifier VR at the Center and adjust RV4 to attain 1Khz sine wave of SSB at 66dBuVEMF.
Check the balancing of Sensitivity in AM/FM and SSB in Band A, E and J adjust L27 and L25 to attain maximum balancing .
Squelch and Meter Alignment:
Since Squelch and Meter have same Trimmer for alignment, we align first the squelch at 66dBuVEMF(1mV) and check only the RX Meter(9th Bar will on between 40 to 60 dBuVEMF)
Versions with a SS301F PCB
Versions with a SS301M PCB