RCI 2950 / Mirage 2950
Frequency Modification


Old Version

Locate the main PCB with Jumpers on it.  It is located behind the display board.  Find jumper J2.  If you clip this jumper, you'll have 26.000-29.700Mhz.  If you place the jumper on Pins P1 and P2, you will have 26.000-32.000Mhz.  After you "Jump" your radio, you'll need to press the CPU reset button located below J2.


New Version

Real easy to modify!  There are a set of Jumpers on the back side of the display board marked  "J1" and "J2".  One set has a jumper already on it.  Remove it and put it on the 2 pins next to it and you'll have 26-29.7mhz.  If you jump both set of pins, you'll have 26-32mhz.  That's it!


Before you "Peak Out" your radio, you might want to change Q51 from a 2SB754 to a 2SB688 or 2SB817.  The 2SB754 is a 60 watt, 7 amp power regulator.  The 2SB688 is a 80 watt, 8 amp regulator.  The 2SB817 is a 100 watt, 12 amp regulator.  The 2SB688 is ok, but the 2SB817 is best.


Modulation

Most people remove Q32, which is the modulation limiter.  Yes, this gives you an increase in modulation on AM, but it "garbles" badly on SSB.  It also disables VR12 (SSB ALC) and variable power for SSB.  I do not recommend this.  There are (2) other ways to get great modulation on both AM and SSB.
    
     1) Buy a good after-market powermike.
     2) Locate R178 and change to a 3k ohm.  Locate R194 and change to a 4.7k ohm. 
         Locate R281 and change to a 10k ohm resister.  Re-adjust VR14 (AMC) for 
         maxamum forward modulation.  If you decide to use a powermike, you'll have have
         to change this modification back.  If you don't, you'll have overmodulation.


Restoring Power

                                                                                
**Note**

There are 2 ways you can do this mod.  The 1st way will increase your deadkey, but will lose some of the swing.  I like the 2nd way better.  This way will allow your dead key to be lower.  With a lower dead key it will allow more drive voltage to be availble to the modulators which in turn are now driving the RF driver and final transistors.



1) Place the radio with the display facing you, component side up.  Towards the back left corner is a silver Alu board standing up vertically between 3 pins.  Pull the board straight out.  Solder a piece of 16-22 gauge wire from the middle pin to the positive power on the back side of the power cord.  Then solder another wire between the 2 outside pins.  Turn RF power knob all the way counterclock wise.  Turn mode to AM.  Adjust VR15 for 2 watts deadkey.  Turn RF power all the way clockwise.  Adjust VR13 for maximum dead-key. (about 12-15 watts)  Turn mode to LSB.  Turn RF knob all the way counterclock wise.  Adjust VR16 (SSB low power  ALC) for 5-6 watts PEP.  Turn RF knob all the way clockwise.  Adjust VR12 (SSB high power ALC) for maximum swing.  Then turn it back just alittle.  You should see a AM swing of about 20-30 watts and 25-40 watts on SSB.  If you're "gutsy", you can tune L10, L13, L14, L34, and L46 in AM mode for a few extra watts.  If you want a higher dead-key on AM, parallel 330pf caps across C261, C262, and C270.  This will get you closer to a 20 watt dead-key.


2)  To do this mod, you will need a 1N914 diode and a 50 ohms resistor. Locate Q51 which is the 2SB754 transistor.  Hook up as the drawing shows.  This will give you super modulation at whatever power range you want.
Other Tips

If you change D34and D35 from 1N60s to ECG583, this will improve your AM detection.  Distant stations will come in stronger and clearer.  If you use ECG583 for D1 and D2, it'll give you a more effective noise blanker.


If you remove or "Clip"  D-78 you'll have talkback for your 2950.  However it seemed to be alittle distorted.  I found that if you replace D-115 with a .0047uF capacitor it'll improve the sound.  You might want to install a switch inline so that you can turn it on and off.


For an icrease in receive gain, change Q18 to a 2SC2999.  The 2SC2999 transister has higher gain, lower noise characteristics.  You will need to re-adjust L8 and L9.  The gain will improve with more than 3 to 6 db with the same signal to noise ratio.


To increase audio quality and low power swing, change Q53 from a 2SA1869 to a 2SA473, 2SA1012, or a ECG-NTE 153.  (some Ranger/Mirage 2950's already come with a 2SA473)  The 2SA473 and 2SA1012 are ok, but the ECG-NTE 153 is best.



Variable Adjustments

VR1-  AM  "S" Meter                      VR12-  Sideband High Power (ALC)
VR2-  Sideband  "S" Meter              VR13-  AM high Power
VR3-  Sideband Squelch                   VR14-  Modulation
VR4-  AM Squelch                           VR15-  AM Low Power
VR7-  Carrier Balance                     VR16-  Sideband Low Power (ALC)
VR8-  RF Power Meter                     VR21-  FM Deviation
VR11-  Driver Bias

Microphone Pin Placement

1: Ground
2: Modulation
3: TX
4: RX
5: Channel Up
6: Channel Down
Unlocking the Clarifier

When you modify the clarifier it will not track on the display (it will give you about 1.5 Khz shift either way) but you will find it useful in CB mode because the frequency cannot be adjusted.  It is also eseful when using the rig mobile.  You don't have to keep pushing the SHIFT key.  First, locate the wire harness that runs from the clarifier pot to the circuit board.  Just in front of where it plugs into theboard, you will see R-197 (this resistor usually has wax on it).  Clip the top of the resistor.  Now get a 6" piece of wire and solder it to the stub of wire sticking out of the board (not to the top of the resistor itself).  Connect the other end of the wire to pin 3 of IC6. Pin 3 is the leg closest to the front of the radio.  Next, locate D-59, just to the left of the clarifier harness.  It is a 1N4148 diode.  Cut the wire part of this diode to disable it.  If realignment is necessary, use L27 for AM, L28 and L29 for USB.  If you have any problems with close stations being garbled sounding, its because of front-end overload.  Find R-49 in the middle of the board (100k resistor), and change it to a 33k resistor.


Mod for faster scan speed

First take the radios top and bottom covers off.  Then remove all the dials off the front face plate.  Then take out the screws that hold the front face plate.  Now you're looking at the LCD and button printed circuit board.  Remove the LCD printed board.  Now you should see the main processer board.  Lay the radio so that you can see the component.  Now look at the board that has the processer on it.  If you look at the back side of the boardwhere the batterygoes you should see a
blue rectangle shaped resonater marked 2.00g or 2.000 or 2000 kc that would have a x1 or x2 number on the board near it that is also listed in the service manual as a resonator/crystal.  If you change this cyrstal with a 8 mhz crystal, it will make your processor run faster in turn giving you faster up/down on your mike, faster scan speed, faster memory scan, and a shorter roger beep (simular to a HR2510). Do not use anything higher than 8mhz! It will lock up your radio otherwise.
RCI 2950, 2970, & 2990 ALIGNMENT PROCEDURE
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1.0 INTRODUCTION

The following steps are required to re-align the RCI-2950/2970.
CAUTION: Alignment should only be attempted by personnel trained in RF product testing and alignment.
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PLL SYNTHESIZER / OSCILLATOR FREQUENCY ALIGNMENT
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1.1 Connect digital voltmeter to jumper J13. Adjust L17 for a reading of 2.2 VDC 0.1 volts

1.2 Connect digital voltmeter to pin 3 of IC7. Adjust L21 to 1.2 VDC 0.1

1.3 Connect a frequency counter to L61 and adjust VC1 for a reading of 10.240 MHz 10Hz

1.4 Connect a 50 ohm dummy load to the antenna connector

1.5 Connect a frequency counter to pin 3 of IC14. Ensure that the clarifier is precisely at the 12 o'clock position. Adjust
VC2 for 10.240 MHz 10 Hz. Key the transmitter and adjust VR21 for 10.240 MHz 10 Hz.

1.6 Connect a frequency counter to the cathode of D45. Put mode selector on AM. Key the transmitter and adjust L27 for
10.6950 MHz 10Hz.

1.7 Adjust VR7 fully clockwise. Leave the frequency counter connected to D45. Put the mode selector on USB. Key the transmitter and adjust L29 for 10.6925 MHz 10 Hz.

1.8 Put the mode selector in LSB. Key the transmitter and adjust L28 to 10.6975 MHz 10Hz. Return VR7 to
approximately the middle of rotation.

1.9 Put the mode selector in AM. Connect X10 probe to pin 13, IC17 Check the frequency counter for 5.930 MHz.

1.10 Set the oscilloscope for 50nS (.05uS) per division on the vertical input. Connect X10 probe to IC17 pin 13 and very
carefully adjust L24 and L25 for the best waveform.



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RECEIVER ALIGNMENT
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2.1 Put the mode selector in FM, the RF gain fully clockwise, Clarifier at 12 o'clock and the frequency at 28.0300 MHz

2.2 Connect an FM signal generator to the antenna connector. Set the modulation for 3 kHz, output level at 0.5uV.

2.3 Connect a SINAD meter to the external speaker jack, adjust volume to approximately 10 o'clock.

2.4 Connect X10 probe to the cathode of D12. Set oscilloscope sweep selector for 1ms per division and vertical input
selector for 10mv per division.

2.5 Adjust L8 for the best SINAD reading and the least distortion wave form on the scope. Do not try tuning this coil for
the maximum, as this will result in degraded performance.

2.6 Adjust L9,L11,L12,L13,L14,L4,L3,L5 and L6 for maximum on scope. Reduce generator if necessary, so as not to
exceed vertical height on scope.

2.7 Adjust L6 and L5 for best SINAD

2.8 Put mode selector on LSB. Signal generator to 28.0290 MHz, modulation of output level at 0.5uV. Tune L15 and
L16 for maximum waveform on scope.



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TRANSMITTER ALIGNMENT
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RCI-2970 LEVELS ARE SHOWN IN [ ]

3.1 Connect an audio generator to pin 2 and ground (pin 1) of the Mic connector. The Mic gain should be fully
counterclockwise. Set generator for 30mV RMS., 1 kHz sinewave

3.2 Adjust VR14 fully counterclockwise

3.3 Adjust VR12 fully counterclockwise.

3.4 Connect a wattmeter and 50 ohm dummy load to the antenna connector. Set the wattmeter for 30W scales [100W]

3.5 Key the transmitter and slowly increase the Mic gain until you obtain approximately 10W. Adjust L19, L48, L47 and
L43 for maximum reading on the wattmeter. Reduce Mic gain if necessary to maintain about 10 to 15W on wattmeter
[40-50W].

3.6 Increase the Mic gain to maximum (fully clockwise). Key transmitter and adjust L34 for maximum power output.
Power will typically be 30-35W [100-120W].

3.7 With the Mic gain still maximum of LSB, key the transmitter and adjust VR12 for 25W [100W].

3.8 Put the mode selector on AM. Key the transmitter with no modulation applied and adjust VR13 for 10W [50W].

3.9 With the mode selector still on AM, re-connect 1 kHz audio the generator to radio and key transmitter. With Mic gain at
maximum, adjust VR14 for 90% modulation. Use the mod meter or oscilloscope with RF sampler [85%].

3.10 Put the mode selector on FM. Key the transmitter and check for 4 kHz deviation 0.5 kHz. There is no deviation
adjustment provided in this radio. Simply check for sufficient transmit audio. Use the deviation meter or the
service monitor.
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