The only difference between the old and new versions of the RCI2950 is the new CPU board. They require slightly different modifications. The new version only covers 26 Mhz to 30Mhz
The old version of this radio can be expanded from 26 Mhz to 32 Mhz. Although the use of the 30 -32 Mhz range may need realignment. First find the PC board with the jumpers on (behind the front pannel).Then find 'J2',there is a jumper on pins P3 and P4.If this is jumper is removed you will get coverage from 26 Mhz to 29.7 Mhz. If this jumper is then place on P1 and P2 coverage will be from 26 Mhz to 32 Mhz(retuning may be needed to operate in 30-32 Mhz range). The CPU now needs to be reset by pressing the button located below 'J2'
As the CPU
board has changed the modification is different. On the
CPU board there is only one jumper with two positions
available. In one position it covers 28 Mhz to 30 Mhz, In
the other it covers 26 Mhz to 30 Mhz.
Frequency Modification on new Versions
Remove the bottom cover to gain access to the small PC board immediately behind the front panel. There will be a set of jumpers marked "J1" and "J2". Move the jumper from the top two pins to the bottom two pins. Frequency coverage will now be expanded to 26mhz-29.7mhz.
Press the "MAN" button to switch between CB operation and normal operation.
Press the "SHF" button while in CB mode to switch between CB channel readout and frequency readout.
Press the "ENT" button while in CB mode for instand channel 9.
*NOTE: The battery and the CPU reset have been eliminated in the newer versions, the new system uses memory capacitors for memory backup
IF YOU FILL BOTH PINS J1 AND J2 ON THE NEW VERSION OF THE RANGER 2950 YOU WILL GET 26.000-32.000 JUST LIKE THE OLD VERSION.THE SAME FOR THE 2970.
First take the radio's 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 circuit board .Now you should see the main proseser board. Lay the radio so that the solder side of the big main board is solder side down so that you can see the components. Now look at the board that has the processer on it. If you look at the back side of the board (proseser board) where the battery goes you should see a blue rectangular shaped resonater marked 2.00g or 2.000 or 2000 kc that also would have a x1 or x2 etc number on the board near it that is also listed in the service manual as a resonator/crystal. If you change the value of this part (remove it and replace it with a crystal ) with a value of 8mhz will make the proseser run faster in turn giving you faster up\down on your mic, faster scan speed, faster memory scan, a shorter rodger beep sounds like or similar to 2510. My self when i experimented with my own radio i ran into trouble when i used a crystall with a value of 14mhz
14mhz (works but locks up the radio from time to time)
12mhz (was preaty much the same but didn't lock it up as much)
10mhz (worked fine but I wanted to run with 8mhz just to make sure)(the radio worked good in all mods all the time)
8mhz (would be what I would recomend not as fast as the others but is a lot more stable for daily usage and is a lot faster than stock
BE SURE WHEN DOING THIS MOD YOU ARE CAREFUL NOT TO DAMAGE THE CIRCUIT BOARD AS MOST OF IT IS SURFACE MOUNT THE TRACES DAMAGE VERY EASILY
THE RESONATER IS STANDERD SIZE OF A CRYSTALL REMOVE THE RESONATER AND REPLACE IT WITH A CRYSTALL WITH WIRE LEADS NOT THE STANDARED PLUG IN TYPE AS THEY WONT FIT
My method of desoldering the resonater was with a solder sucker with a heated tip.
Where to get crystalls? old pc/xt/at motherboards from computers
To assemble radio just do the reverse of the dissasembly
You should take care when you try and modify the wirings of microphones because of the presence of +12 volts on one pin of the plug. This particular feature may damage mikes. This is also a nice infrmation for those who would like to modifiy their pre-amplified mikes so as to get a rid of the 9 volts battery ( A small mod with a Zener diod should make the 12 volts voltage fall down do 9 volts. It'll be perfect to feed the mike pre-amplification circuits).
which is a 2SB754. This part should be subbed out with a
2SB688 but doesn't have to be. The 2SB688 is a heavier
duty and higher wattage transistor. To do this mod, you
will need a 1N914 diode and a 50 ohms resistor. Hook up
as drawing shows. This will give you super modulation at
whatever power range you want.
& D35 that are 1N60's by ECG553 or SK9975. This mod
will enhance the radio performance.
Older 2950's with batter backup will discarge the battery if the power source is removed and the radio is left in the "ON" position. This causes corruption in the memory circuits and in the microprocessor. This can cause the failure to turn on....lights on... and nothing else.
heat dissapation and durability and a decrease of
transmit voltage drop change Q-51 to an ECG37 or equiv.
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