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New ! D78 location diagrams !
New technical page + Pics
Post your own mod and get published here !
Coverage Expansion - 26 to 32 Mhz !
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
Old Version
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'
New VersionAs 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
And...
FROM "Smokin Joe" UHEH98A@PRODIGY.COM - Planet11@aol.comIF 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. TRY IT IF YOU HAVENT YET. Please E-mail me if any problems.Or call me at work.More than happy to help.Happy Converting.....Joe
Tri-State Communications 1151 Stone Dr.# D4 , Harrison,Ohio 45030 . Tel 513-367-5455 513-367-5755 Fax . Ask For Joe,Store Manager.
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 downso that you can see the components. Now look at the board that has the proseser 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
CAUTION:::::::::::
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 otherwise you will pay about $10cdn for them.
To assemble radio just do the reverse of the dissasembly
From: IAN SMITH
For CBers, here is a channel map.
How to wire the Microphone plug !
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).
Heavy swinger mod (modulation)
Kindly explained by bobg@bright.net
Locate Q51 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.
Change D34 & D35 that are 1N60's by ECG583 or SK9975. This mod will enhance the radio performance.
TALK BACK Modification
Kindly explained by John Williams ghost@sccoast.netWell here go's The talk back is done by cliping one end of D-78. or you can wire a spdt switch to switch on and off! I hope this info gets me the way to unencrypte the RCIbible that you have ! Mine seams to be a bit different! By the Way I think the RCI's are the best radio's on the market but I did hear a rumor that thay may be closeing there doors at the end of the year .I hope it's only a rumor! GOOD MODS.
and also from:
Bill Eitner kd6tas@earthlink.net
A common way to obtain talk-back on the 2950 is to lift one leg of the diode marked D-78. Many times, a switch is installed to create a switchable talk-back. This is probably not the only way to enable the talk-back feature, but it's an easy way. To disable the talk-back, make sure there's a 1N914 type diode in the D-78 position. If that doesn't work, trace the D-78 circuit to make sure nobody performed the mod by cutting a trace on the solder side of the board. To locate D-78, remove the covers. Orient the radio with the speaker side up, and the display facing you. In the upper right quadrant, you'll see IC-14 (the audio IC) mounted to the chassis. You'll also see T-1 to the left of IC-14. D-78 is toward the front of the radio a bit from T-1. I hope this helps and good luck..
Remark from Eric erice@fvmail.com WEB: http://www.boomerscb.com
The removal of D-78 will indeed provide a talk-back, but it will be very scratchy and distorted. Try it this way instead:
- 1. Cut D-78 . Wire a SPST switch in series with D-78 to make it switchable.
2. Replace D-115 with a .0047uF disc cap.You will now have a clear and natural sounding talkback guaranteed to make you smile!
Eric at Boomers CB Sales
Util Tricks
Courtesy from Michael Smoot msmoot@tristate.pgh.netI've just read thru the FAQ'S area of your web page, and their is a few things that need to be added to the rci 2950 cures. First of all:
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.
Also found other faults:
The 8 volt regulator that is on the left side of the radio (speaker side up, front closest to you) the regulator favors the front of the radio....anyhow... I have seen 3 or 4 radios that had the turn on with no receive or transmit. The cause: cold solder joint on the regulator, this could be caused by the stressing of the chassis during mobile installation or dropping, bumping of the radio. The cure: remove old solder from regulator and resolder. Don't attempt to remove the regulator from the chassis, it's attached there for a reason... heatsink....
One other fault:
Warbaling on ssb.... Be sure to use the proper power cord that came with the radio... don't use the radio shack substitution. The wire guage is smaller and thus won't be able to pass enough current thru the wires. This causes the warbaling effect on ssb. Also try turning down the mic gain on ssb when running a power mic.
Oooopppsss! forgot one other thing!
Wire the radio backwards (reverse polarity) usually causes the power regulator for AM to short out. This will give the radio a 40 Watt carrier with no modulation. This is not to be done intentionally.... just letting you know what the radio is able to do without power control.
Hope this info helps out... If you have any questions that I might be able to help out with, post them in the RCI Mailing List. I would like to be a part of the "GROUP".
2950 Tune up/Mod
Again from a fantastic visitor : bobg@bright.netTo increase heat dissapation and durability and a decrease of transmit voltage drop change Q-51 to an ECG37 or equiv.
To prevent overheating and increase audio Quality & low pwr swing change Q53 to a 2SA473
To improve low power swing on AM locate R178 and change to a 3k ohm.The resesitor you just removed save for the next step.(4.7k)
Locate R194 (10k ohm) replace with the 4.7k resistor from previous step.
Locate R281 (4.7k ohm) replace with the 10k resistor from the previous step.
For increased output on SSB and AM locate C270 and parallel with a 470pF-1kv ceramic disc capacitor.
Replace all plastic insulators with mica insulators on all transistors. Use a liberal amount of heat sink compound.
For improved modulation remove Q32, which is the modulation limiter.
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