| Author |
Message |
    
Gunship
| | Posted on Wednesday, August 20, 2003 - 6:05 am: | 
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1.) Center clarifier knob and tape it so it doesn't move.
2.)Clip one side of D-52 and R44.
3.) Remove R174 and replace with a wire jumper.
4.)Follow the leads from clarifier and clip off white and yellow at board.
5.) Solder a wire onto the yellow and run to pin 3 of IC4 located next to audio-output chip(pin 3 is third from back of readio)
6.)Solder a 4.7 K,1/4watt resistor to the white and solder to board ground at point just past the mtg.screw by 8719( Try to keep the wire as short as possible).
You should now have an unlocked clarifier with 7 KC of swing on each side Both xmit and rcv will track with the clarifier, If the clarifier is off-center set radio to chan 20(27.205) AM and, with a freq.counter, adjust L59(VCO) to 27.205 with knob centered. |
Adshar64
| | Posted on Wednesday, August 20, 2003 - 4:03 pm: |
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L59 is not vco. L19 is vco tune range and L20 vco rf output.You need to tune L59 (LSB) with the audio offset allowed for; ie 27.204 with 1000hz audio injection,and 27.206 on the USB slug, unless you do a factory alignment on the 34mhz and 7.8 mhz sections using the testpoints.Id rather have 3kc up and 11kc down on a clarifier mod than what I feel here is a waste of range.A lot of uprange is wasted when you can go up a channel and pick up any ch gaps with a 10kc or more downrange.A easy way to keep centre clarifier is just refit the knob to that effect and align the modes as above so no retune on mode change at centre clarifier is necessary I normally fully clockwise the knob , take it off and refit to two oclock position then turn back to 12,00 oclock and tune radio for centre there, This allows for a great downrange and plenty up to tune a off frequency station. You will find tune range is different for modes as you go down. USB will need more down knob range than LSB for same kc drop.Bypass of D51 enables more uprange as it elimintes volt drop there.Not using a 4.7k resistor and connect white direct to ground will give more downrange. Different strokes for diff folks. All I'm saying is there's a choice of setups here.
cheers |
Adshar64
| | Posted on Thursday, August 21, 2003 - 4:28 am: |
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Mistake above in my post L59 is the USB slug alignment is;
Input of Freq. Counter To TP-13 (IC-1 Pin 8)
CH-19 -------------------------------- Check for 10.240Mhz.
Input of Scope To TP-10
CH-19 AM ------ Adjust L-21 for Maximum RF (3-4vPP Typical)
Input of DC Meter To TP-9
CH-40 AM
Adjust L-19 for 3.2 Volts DC - 2.2 Volts DC on CH-1
Input of Scope To TP-1
CH-19 AM -------- Adjust L-20 for Max RF (190 MvPP Typical)
Input of Frequency Counter To TP-1
CH-1 AM ----------- Adjust L-23 for 34.7650 Mhz. +/- 20 Hz.
CH-1 USB ---------- Adjust L-59 for 34.7665 Mhz. +/- 20 Hz.
CH-1 LSB ---------- Adjust L-22 for 34.7635 Mhz. +/- 20 Hz.
Input of Frequency Counter To TP-10
CH-1 AM -------------------------------- Check for .790Mhz.
Input of Frequency Counter To TP-3
CH-19 USB ------- Adjust CT-2 for 7.8015 Mhz. +5 Hz. -0 Hz.
CH-19 LSB ------- Adjust L-30 for 7.7985 Mhz. +0 Hz. -5 Hz.
CH-19 AM XMT - Disconnect TP-7, TP-8 and transmit, Adjust L-31 for 7.8000 Mhz. +/- 5 Hz.
Input of Frequency Counter To TP-15 (FET-1 Gate 1)
CH-19 AM ----------------------------- Check for 7.3450Mhz.
Input of Frequency Counter To Antenna Input
CH-1 AM ------------------------ Adjust VR-5 for 26.965Mhz.
RECEIVER ALIGNMENT
Set output of Sig Generator to 27.186 Mhz.
Ch. 19, USB ------- Adjust L-14, L-12, L-10, L-9, L-8, L-7
for Max. output at speaker
Set output of Sig Generator to 27.185 Mhz.
Ch. 19, AM - Adjust L-15, L-13, L-3 for Max. output.
Set output of Sig Generator to 27.185 Mhz. Ch. 19, AM - Adjust L-6, L-5, L-4 for Max. output at speaker
NOISE BLANKER ALIGNMENT
Set output of signal generator to 27.185 AM, 1000 Hz. @ 30% modulation.
Input of O-Scope to TP-17, (D-2 Cathode) Inject a 100pps, 1uSec. pulse width signal at antenna input. Switch noise blanker ON
Adjust - L-1, L-2 for a Maximum while maintaining wave form Symmetry
RECEIVER ADJUSTMENTS
Set output of signal generator to 27.185 AM, 1000 Hz. @ 30% modulation.
Output level 1000 uV.
Set Squelch Maximum
Adjust VR-3 so that squelch just breaks.
Set output of signal generator to 27.185 AM, 1000 Hz. @ 30% modulation.
Output level 100 uV.
Adjust VR-1 for s9 on signal meter.
Set output of signal generator to 27.186 USB, 1000 Hz. @ 30% modulation.
Output level 100 uV.
Adjust VR-2 for s9 on signal meter.
TRANSMITTER ALIGNMENT
Input of RF wattmeter to antenna input
Ch. 19 AM
Adjust L-47, L-48, L-46, L-45, L-38 for maximum output
NOTE: Do not touch L-36 (TVI filter), factory adjustment is O.K.
TRANSMITTER ADJUSTMENTS
Input of RF wattmeter to antenna input, no Modulation. Ch. 19 USB, Dynamike MINIMUM
Adjust VR-4 for MINIMUM RF output.
Input of RF wattmeter to antenna input, no Modulation.
Ch. 19 USB, Dynamike MINIMUM
Insert a DC AMP meter at TP-8 (Violet wire)
Adjust VR-9 for 25 mA.
Insert a DC AMP meter at TP-7 (Green wire)
Adjust VR-8 for 50 mA.
Input of RF wattmeter to antenna input,
Inject a two-tone 500 mV signal at mic input, Dynamike MAXIMUM Ch. 19 USB
Adjust VR-11 for 11.0 watts PEP RF output maximum.
Input of RF wattmeter to antenna input Ch. 19 AM, Dynamike MAXIMUM Adjust VR-10 (AM carrier) to 3-4 watts RF output
Input of RF wattmeter to antenna input
Ch. 19 AM
Adjust VR-6 So that it agrees with your output meter. |
Gunship
| | Posted on Friday, August 22, 2003 - 7:02 am: |
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Adshar, You're correct on the VCO. That's what I get for typing from memory instead of my binder. I've found that more than seven KCs of swing necessitates the use of a ten-turn pot to get enough control. Seven is about the most you can accurately use with a stock clarifier knob. It's a matter of personal taste I guess, I prefer it equal in both directions. |
Adshar64
| | Posted on Friday, August 22, 2003 - 5:50 pm: |
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I dont agree on that really. With the 7 up and 7 down you said, if you tuned to have 3 up and 11 down with knob relocate, it would be more useful. Could tune to ch gaps etc. Ten turn pot does make things nice I agree.
depends on ya touch I guess. I find it quite easy up to 20kc. I actually have a cobra 2000 with ~100 kc slide and I can tune it with the coarse with the freq counter helping me bigtime here. Dont believe me?
Go here and look in photo's section for photo demonstration. it actually gets wilder with a 800kc control with xtra band xtals lol. but is quite usable. I must have the right touch lol
see here;
http://groups.yahoo.com/group/Cobra_2000/,http://groups.yahoo.com/group/Cobra_2000/ |
Teham
| | Posted on Sunday, February 08, 2004 - 2:50 pm: |
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I have a Grant XL. All I want to do is unlock the clarifier so transmit and receive both move. Don't want any more swing up or down than what clarifer will do normally. Can this be done and if so how? |
Adshar64
| | Posted on Monday, February 09, 2004 - 6:23 am: |
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Remove D52 or clip one side
Jumper D51 or replace with wire link ie shunted
Disconnect Clarifier positive feed from pcb ie yellow wire and extend to pin3 IC4 ie solder here.
thats it |
Bigbob
| | Posted on Monday, February 09, 2004 - 7:09 pm: |
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I used a MAXI-TUNE diode a ten micro-henry choke in series and a 47 ohm 1 watt metal film resitor instead of the 4.7k for 25 up and 35 down with stock nob and pot on p-400 it has the mb8719 proscessor and no freq counter |
Kc0gxz
| | Posted on Wednesday, February 11, 2004 - 11:32 pm: |
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Adshar64
That sure is a lot of work to go through since it's possible to get a 10Khz jump off of the PLL chip with a flip of a switch.
Also, when using the clarifier to "slide" 10-12Khz, transmit/receive frequency start to split from one another. The farther you go into the slide, the farther they split. Most CBers don't know this because they rarely use their "sliders" while on SSB.
While in the SSB mode, trying to clarify someone 10 or 12Khz down is next to impossible because the farther into the slide you go, the toucher it gets. I find that a clarifier range of only 6 up and 6 down works great since you can get that extra 10Khz "slide" right off the PLL chip.
-------------------------------------------------
If anyone is interested, try this (tried and proven) 10Khz switch mod. It works well with SSB radios using the 8719 chip. It also allows you to easily get all of the "A" Channels. It's best to have a frequency counter. And I'm sure you guys know by now that Copper has them cheaper than anyone else.
1- Locate and cut the trace to pin 16 of PLL chip.
2- Bridge this cut with a 4.7K resistor.
3- Mount a mini SPDT (center-off) toggle switch in a location you prefer.
4- Solder a wire from pin 16 to the center pin of your newly installed switch.
5- Solder a wire from pin 18 to top pin of switch.
6- And last, solder a wire from pin 9 of chip to the bottom pin of the switch.
Pin 18--top
Pin 16--center
Pin 9--bottom
For normal channel use, leave switch in the center position.
Using this 10Khz switch mod in conjunction with a 6Khz up and 6Khz down clarifier range, you will not be missing any frequencies throughout the whole band. Actual clarifier use will be much easier than it would be with a 10 or 12 Khz slide--not near as touchy and no noticable transmit/receive frequency split.
PS: I'm sure this mod has been printed on the forum before at one time or another.
Just my 2 cents worth.
Jeff, kc0gxz. |
Crafter
| | Posted on Thursday, February 12, 2004 - 12:29 am: |
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Bet we have all did that one at least 2 times! I dont know how many times I've done it. |
Yankee
Advanced Member
Username: Yankee
Post Number: 677
Registered: 7-2003
| | Posted on Saturday, June 18, 2005 - 3:28 pm: |
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Just passing though the archives and happened to read Jeff's 10 KHz. plus or minus mod and this is one in the same that I use, and have been useing since Uniden has made the 148s, 2000s, and both of the Grants. Just another 2 cents worth.
Carl CEF-357 |
Keithinatlanta
Advanced Member
Username: Keithinatlanta
Post Number: 715
Registered: 3-2003
| | Posted on Wednesday, December 28, 2005 - 6:03 pm: |
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Yankee, what is purpose of unlocking the clarifier on a CB ssb radio? What more would I get by having this done when it is just a forty channel radio? And yes, it is a Grant XL.
thanks.
Keith |
Yankee
Senior Member
Username: Yankee
Post Number: 1037
Registered: 7-2003
| | Posted on Thursday, December 29, 2005 - 1:11 pm: |
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Hi Keith,
With the +or- 10 KHz. open clarifier it allows the use of the 5 Alfa channels, and also allowing the 5 KHz. drop that many operators through out the world use when operating world wide DX stations.
Many great DX conditions are found on the 5 KHz. down frequency and not on the standard channel frequency. The Uniden Grant XL is much more than a 40 channel sideband radio, as well as the other fine Uniden radios in this same mother board group. |
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