I found directions to unlock the clarifier on my Grant xl. However I cant locate the Ic I am supposed to hook the one of the nob wires to. The number they gave isn't there. Any help?
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Clarifier unlock on Grant xl
- Thread starter Fdtrucker
- Start date
More Dead Presidents
There can't be but so many ICs in there. It is probably the PLL chip. (Marked MB8719 or MB8734, probably). The clarifier mod is probably looking for a 5v or 8v power source, one of such may be located going to the PLL. Also, if the PIN # is, say, 11, and there is only one IC with more than 8 pins in the radio then you have your winner.
There can't be but so many ICs in there. It is probably the PLL chip. (Marked MB8719 or MB8734, probably). The clarifier mod is probably looking for a 5v or 8v power source, one of such may be located going to the PLL. Also, if the PIN # is, say, 11, and there is only one IC with more than 8 pins in the radio then you have your winner.
Thanks! I finally figured it out. It was looking for 8.2 volts. The IC was marked with small numbers barely readable! It works like a charm. The only thing now is that when I am close to some radios I have to crank the clarifier forward to tune them in. Distance is ok. But certain radios this happens with. Like they are off frequency. Is this normal? I can live with it. I just tell them that they are killing me with their big radio. LOL.. 
when you unlock the clarifier you have to realign the frequency of the radio, the fixed voltage you hooked it to is rarely exactly the same as the rx voltage supplied to the clarifier pot on an unmodded radio, i measure the difference and if it is over .7volt i put a diode in series with the wire to lower the voltage a little, then put the radio back on frequency with the clarifier dead center, hope this helps.
I have a frequency counter mounted on the radio. So I know it's on frequncy. Certain radios I cant hear when around 100-200 feet of them. Past that I can hear everyone fine. wierd...
1. Find D52, R44 and R174 and remove them.
2. Solder a jumper from where you removed R174
3. Follow the WHITE WIRE from the clarifier control to where it attatches to the PC board and UNSOLDER it.
4. Resolder this WHITE WIRE to the PC board ground.
5. Follow the ORANGE WIRE from the clarifier control to where it attatches to the PC board and UNSOLDER it.
6. Resolder this ORANGE WIRE to pin 3 of MB3756 Regulator.
NOTE: Some radios have different colored wires on the clarifier control.
They are: YELLOW instead of ORANGE and RED instead of BLUE
If all goes well, you should slide about 4Khz down and 1Khz up
(on one 1991 Phillipines 148 GTL I got 5khz up and 15khz down and the same on a 1993 Phillipines Grant XL .....both were the PC-412 boards I believe they were. Very easy mod that works well ....I was told a while back that some will give more then others. (The mod info was borrowed from Defpom)
2. Solder a jumper from where you removed R174
3. Follow the WHITE WIRE from the clarifier control to where it attatches to the PC board and UNSOLDER it.
4. Resolder this WHITE WIRE to the PC board ground.
5. Follow the ORANGE WIRE from the clarifier control to where it attatches to the PC board and UNSOLDER it.
6. Resolder this ORANGE WIRE to pin 3 of MB3756 Regulator.
NOTE: Some radios have different colored wires on the clarifier control.
They are: YELLOW instead of ORANGE and RED instead of BLUE
If all goes well, you should slide about 4Khz down and 1Khz up
(on one 1991 Phillipines 148 GTL I got 5khz up and 15khz down and the same on a 1993 Phillipines Grant XL .....both were the PC-412 boards I believe they were. Very easy mod that works well ....I was told a while back that some will give more then others. (The mod info was borrowed from Defpom)
I did another mod. It gives +/- 6 khz with the knob centered at 1200.
Jump r175
remove r100
jump d51
remove r139
remove r44
disconnect clarifier lead and connect topin 3 of ic4 (8.2 volts)
replace r174 with 3k3
run a 12k res. from the d51 jumper in series and connect to pin 3 also.
It works fine like I said. lots of dx contacts from my truck in NY to Alabama Carolinas Kentucky etc.. no problems. Maybe its the radios around me.. Its only a couple of people.
Jump r175
remove r100
jump d51
remove r139
remove r44
disconnect clarifier lead and connect topin 3 of ic4 (8.2 volts)
replace r174 with 3k3
run a 12k res. from the d51 jumper in series and connect to pin 3 also.
It works fine like I said. lots of dx contacts from my truck in NY to Alabama Carolinas Kentucky etc.. no problems. Maybe its the radios around me.. Its only a couple of people.
Right On FDT !! Good to hear you pulled it off !! Nice to know we can do a few things for ourselves once in a while with help from others where it isn't a damned dollar sign involved everytime ,yeah !! so it may not be perfect but like you said ,it's getting the job done for you ....and you are what matters the most !! (-: Hat's off to Defpom and others like him who can take the time to share the knowledge .....like I said ..it may not be perfect but ballpark will work and the satisfaction that "we" can sometimes do things for ourselves can tend to make one feel pretty good about it and to just be a added enjoyment to our hobbies. SK
It cost less than a dollar for the parts. and enjoyed doing it. I got all the drivers out here wanting to get channel mods for their own radios so they can go up to the channels I hang out on..