Here's the story on the clarifier mods...All CB radios and many "10 meter radios" come with a clarifier that only tracks on the receive. Therefore, if you move your clarifier to tune someone in, you are not transmitting on the same frequency as them, you are only RECEIVING their frequency.
The "locked" clarifier is fine if you are talking to one person on SSB, or all of your SSB radios are tuned exactly the same. This hardly happens and the factory tuning of CB radios is almost never exact.
You also do not need your clarifier unlocked if you are a channel 19 guy or an AM only guy, unless you want to get the "in between channels." I would recommend the clarifier mod for SSB or CW operators only.
I would never run a cb radio or a 10 meter radio with a clarifier that didn't track on transmit, and it used to drive me crazy when I couldn't find the mods, so this is a page to list some clarifier mods, many of which I have done so I may be able to help.
The following are some clarifier mods I have collected from various sources. I also through in a few hard to find adjustments for particular radios.
I am not responsible for you screwing up your radio. If you do not know what you are doing, practice on your own radio, not someone else's. If you find a mod you want, highlight it, copy it and paste it in microsoft word, works, or notepad. That way you don't print out the whole page!
If you are searching for a particular mod hit Ctrl + F at the same time and type in the box the radio you are trying to find.
1. Remove JP195
2. Remove JP196
3. Place wire from J14 pin +8V to J9 pin F1
UNLOCKING THE CLARIFIER
Out of the box the Delta Force clarifier control tracks only receive. Follow the steps Below to have the clarifier track on both the receive and transmit.1. Turn off radio and disconnect from power source.
2. Remove both top and bottom cabinets.
3. Locate and unsolder the diode at D176.
4. Locate and unsolder the resistor at R244. Save this resistor for a later step.
5. Locate and unsolder the resistor at R306. Replace R306 with a jumper wire.
6. Locate the variable resistor at RV-108. Find the leg of RV108 that is closest to the R244 resistor location and cut it from the circuit board.
7. Position the radio with the face towards you and the solder side of the main circuit board up.
8. Locate the R244 circuit board pad that is closest to the front of radio. Follow this trace to the pin on the white edge connector. Take the removed resistor from R244 (step 3) and solder one leg of the resistor to this pin. Count over 2 pins to the right (this pin should be 8 volts DC) and solder the other leg of the resistor to this +8 volt pin.
9. Turn the radio over and locate the gray wire on the clarifier front panel control potentiometer. Follow the gray wire to the 12-pin connector and cut the gray wire by this connector.
10. Solder the gray wire to the junction of RV108 and D176. Use the hole at the junction where D176 was removed.
11. Put the front panel clarifier control in the 12 o'clock (center) position and adjust RV108 for center frequency.
1. Remove top cover.Channel Modification:
2. Locate jumpers J94 and J132 on main PCB.
3. Cut J132.
4. Add a jumper wire from J94 to cut side of J132 closest to X2.
1: Remove top cover.
2: Locate the back of the display boad.
3: On this board you should see two pins SJ3, Connect a jumer wire between the pins.
4: Power on the unit holding the EMG/CH9 button remember to hold the button for about 5 seconds after power is applied.
To change bands just press EMG/ CH9 button.
(Coverage from 25.165-29.665Mhz)
* VR4 AM carrier * VR5 Modulation * VR14 ALC ssb
1. Cut R187 and D36
2. Find the red and orange wires coming off the clarifier knob. Cut them where they connect to the PCB.
3)Take the red wire and solder it to pin #3 of the MB3756 IC. Solder the orange wire to PCB ground.
NOTICE: On some radios the red and orange might have to be reversed to slide in the right direction.
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Clarifier mod for President Grant and Madison MB8719 PLL (THE 5 PIN MIC MODELS) .
Clarifier mod:
1)Cut D-52 and r-148. Find R-174 and solder a wire across the resistor.
2)Find the RED wire that comes off the clarifier control and cut it just before it connects to the PCB. Take that wire and solder it to GROUND on the PCB.
3)Cut the orange wire just like the red wire but solder this wire to pin # 3 if IC-4 the MB3756 IC regulator.
This should give you about 5 khz is slide on this radio.HOME
Clarifier mod for President Washington and similar 858 PLL (4 pin mic)models
Clarifier mod:
1. UNSOLDER and remove D30.
2. UNSOLDER and remove D29.
3. Add a jumper in the holes from where you removed D29.
4. Cut the end of R119 that is closest to D29.
5. Add a jumper wire from R119 (the cut end) to the banded end of D44.
6. Follow the PURPLE/WHITE wire form the clarifier control to the PC board and UNSOLDER IT.
7. Re-solder this wire to the PC board ground.
8. If all went well, you should slide 1 kc up and 3 kc down.
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Midland 79-290 Clarifier mods
I did the following clarifier mod on a 79-290, and the radio never was the same. It could be that I was not careful with my work, but I ended up beating the shit out of the radio. I do not recommend any clarifier mod for this radio. They could have been good radios, but in my opinion, are very cheaply and shoddily built.
Proceed with the following mod at your own risk, if you have a better one email me: jake949 AT msn.com
Clarifier mod:
1. REMOVE R306. R306 is 1Kohm & is located on front PCB, R305 is 6.8Kohm and is located on front PCB.
2. REMOVE R105. R105 is on the Main PCB bottom.
3. REMOVE D27 AND 27A. D27/27A is a three legged Diode located on the Main PCB bottom.
4. JUMPER: R305, D27A.
5. Prepare a 6" jumper wire and attach a 1/8 watt 10Kohm resistor to it (insulate the connection).
6. Connect one end to emitter of Q61 (leg nearest rear of unit). Connect the other end to the solder pad nearest the center of the radio that was left vacant by the removal of R306.
7. Tune AM, LSB, USB with T14, 15, 16 to same location on clarifier. Center clarifier by tuning can that is nearest front Main PCB left corner next to the crystal.
8. This transformer has different numbers in different production runs as do T14-16.
9. Once clarifier is centered it should slide 10KCs but may drop out on one end or the other so be careful!
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Clarifier mod for President Lincoln, HR2510
Clarifier Mods:
1. Find D150 on the main circuit board. With the radio right side up, it will be found in the front right-hand corner of the PCB. Lift or clip one end of this diode.Clarifier Mod 2
2. Find the orange wire comming from the RIT/RF GAIN PCB (PB-120). From there it goes to the main PCB to a 4 wire connector (Yellow/Orange/Red/Brown) located on the left side of the main PCB near the center of the radio. Clip the orange wire from the connector and feed it through to the other side of the radio. Solder it to pin 3 of IC 311. This will be a three-pin voltage regulator located just to the right of the large microprocessor (IC315). The pins on IC 311 are numbered from left to right.
To center the clarifier:
1. Locate the 3 tuning coils on the front left corner of the main PCB.
2. The extreme left coil labeled L116, adjusts USB. The center coil is labeled L118, adjusts LSB. The right coil labeled L117, adjusts CW.
3. There will be some interaction between the coil adjustments so you may need to repeat retuning a few times. I suggest you start with the USB coil and end with the CW coil. The Mod will give you plus or minus 3 Khz slide, the clarifier will NOT change the display, but the transmit and receive frequency will track together now.
THIS IS THE ONE I DO
1. Cut D150 on the main PCB.
2. Locate the orange wire at the top of the RIT PCB, cut and connect to pin 3 of IC107. This is a 3 pin transistor bolted to the left side of the case next to VR116. Pin 3 is the lead closest to the back of the radio. You now have +/- 5khz slide.
Clarifier Mod 3
1. Find the orange wire comming from the RIT/RF GAIN PCB (PB-120).To Adjust:
2. From there it goes to the main PCB to a 4 wire connector (Yellow/Orange/Red/Brown) located on the left side of the main PCB near the center of the radio. Clip the orange wire from the connector.
3. Find the red wire (8 Volts) on the mode switch PCB and solder the orange wire to it.
1. Set the clarifier to center (12 o’clock) and the Mode switch to AM Frequency to 28.000 Mhz. 2. Connect a Frequency counter to TP306. Adjust L315 for 6.200Mhz
3. Connect a Frequency counter to TP304. Adjust L318 for 38.695Mhz
4. Connect a frequency counter to TP1.
5. Set the Mode switch to USB, adjust L116 for 10.6975Mhz.
6. Set the Mode switch to LSB, adjust L118 for 10.6925Mhz.
7. Set the Mode switch to CW, adjust L117 for 10.6950Mhz.
8. Check clarifier's range. It should be +/- 4Khz.
Clarifier mod 4
1. Find the orange wire comming from the RIT/RF GAIN PCB (PB-120). From there it goes to the main PCB to a 4 wire connector (Yellow/Orange/Red/Brown) located on the left side of the main PCB near the center of the radio.
2. Clip the orange wire from the connector. Solder the orange wire to Jumper 13 (JP13) +8V constant.
3. Cut D150.
To center the clarifier: With the Mode switch to AM, Frequency at 28.000Mhz, clarifier at 12 o’clock, connect a frequency counter to TP304, adjust L318 for 38.695Mhz.
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Clarifier mod for TRC 448 (PLL REC 86345).
FYI, this radio has dual audio output transitors and high level AM modulation. Nice old radio. This info is second hand information from a good source, but I have never tried it:
Clarifier mod:
1. Remove d15
2. One side of the clarifier is on ground. Leave it.
3. Cut the wire hooked to the other side, leave enough length to connect to the positive (+) side of C333. LEAVE THE CENTER WIRE ALONE.
4. TC-4 adjusts AM Frequency and TC 5 Adjusts SSB frequency.
5. This should give you +/- 2-3 khz slide, usually enough for someone on a certified CB channel.
Adjustments:
*AMC VR5
*ALC VR204
*AM DEADKEY VR210
*SSB MIC GAIN VR4
RCI Ranger 2950/2970 non DX models.
This mod may work on DX models but I am not sure. I found it in my notes and could not find it anywhere on the web so here it is:1. Find the clarifier harness. Find r-197. CLIP THE TOP. Do not remove.
2. Get a wire and solder it to the stub of wire from the resisitor. Do not solder to the resistor.
3. Connect other end of the wire to PIN 3 of IC6. This is the pin closest to the front of the radio.
4. Locate D59. It is to the left of the clarifier harness. Cut the wire part of the diode to disable.
5. Use L27-AM, L28-LSB, L29-USB for realignment if necessary.
RCI Ranger 2950DX/2970DX DX MODELS
1. Remove D63 located near VR8 TX Frequency pot.
2. At J28 cut the black wire close to the connector
3. solder it to point marked 8V on J29. See photos below.
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