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Modifications for the Alinco DJ-120

 

Extended frequency for Alinco DJ-120
Adjustment points for DJ-120T

 

 

 
Extended frequency for Alinco DJ-120
 
     

Hi all, i have recently heard of a mod for the alinco dj-120. The mod opens up transmit from 130 mhz to 174 MHz.
To do this, please follow these simple procedures:
 
  1. Open the front and top case of the ht.
  2. Look for 2 jumpers, one vertical, on horizontal next to the microprocessor and cut both of them.
  3. Reset the microprocessor by pressing the reset button on front panel.

Be careful! that will reset all memories stored in the radio
 

 

 
Adjustment points for DJ-120T
 
     

 

1. Transmitting Unit

 

Item Adjustment Point Adjustment Method Spec
1. Frequency adjustment CV301 (Main PCB) Set the unit in the transmission mode at 144.03 MHz and adjust CV301.
(Transceiver tester, counter)		 144.03 MHz
±50 Hz
2. Modulation degree adjustment VR303 (Main PCB) Input a signal of 1 KHz/50mV into the SP/MIC jack and adjust VR303 so that you obtain 4.7 KHz/DEV in the transmission mode. 4.7 KHz
±0.2 KHz
3. Sub audible tone VR401 (RF unit) Set the sub audible tone to 114.8 Hz by DIP Switch and adjust VR401 so that you obtain 800 Hz/Dev. 800 Hz
±50Hz
4. DTMF VR601 (DTMF Unit) Puch [1] in the transmission mode and adjust VR601 so that you obtain 3 KHz/DEV. 3 KHz
±500 Hz

2. Receiving Unit

 

Item Adjustment Point Adjustment Method Spec
1. VCO P/D voltage adjustment L502 (VCO) Adjust L502 so that P/D voltage is 0,5 V at 144.03 MHz. (DC voltmeter) 0.5 V
±0.1 V
2. RF amp L405, 406, 408 & 409
(RF PCB)		 1 KHz, 3.5 KHz/Dev. - 6 dBµ (Meter direct reading). 145.03 MHz, audio output 50 mV/8ohm (Transceiver tester)
Adjust L405, 406, 408 & 409 so that SINAD sensitivity becomes maximum.		 -6 dBµ Max.
3. Squelch Sensitivity VR301 (Main PCB) 1 KHz, 3.5 KHz/Dev, -8 dBµ (Meter direct reading), 145.03 MHz (Transceiver tester).
Turn VR301 counterclockwise from closed conditions and set to a point where the squelch is open.		 -8 dBµ
±1
4. S-meter adjustment VR302 (Main PCB) 1 KHz, 3.5 KHz/Dev, +17 dBµ (Meter direct reading).
Turn VR302 so that [FULL]-bar begins to light.