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Needing a clarifier unlock mod for a Uniden Pro 810e AM/SSB base radio, board # PB122AB.

I see on several sites to clip D25, and D32, then cut the traces to each side of the clarifier pot, solder a wire from one side of the pot to +8V, and solder a wire from the other side of the pot to PCB ground.

When I remove D32, it puts a nasty 60 cycle hum on my receive and pegs my "S" meter. It appears D32 connects to IC3, labeled AN612 (balanced modulator IC?). I reinstalled D32 and all is well again.

Might anyone have a good clarifier mod for this particular radio, perhaps one that will allow me to slide -5kc or better? Any info would be most appreciated, thanks in advance!

After look at the diagram, I would try this first, isolate both the outer connect of the Clarifier pot, connect one to Ground and other to a resistor in the range of 120R to 560R and the other end of the resistor to the 8-volt side of IC4, remove R119 and D25.

You may need to change R118 to a 470uH choke to stop the varicap from becoming unstable.

If the shift is a bit harsh, try cap about 2u2 to 10u from the control line to Ground. The control line is the one, which comes from the centre wiper of the Clarifier pot back to R118.

I do not know how much shift you will get as the varicap used in this radio is only has a 4.5 to 1 ratio and it would be better with one, which has about 10 to 1 like a BB8809, and the xtal maybe have a low pf, which will restrict its loading.

Most excellent, I'll look into this, going to print it out. Thanks a bunch, Rick! Much appreciated!

(edit) Just looked thru my varicaps and I have a varicap that is larger ratio, I'll drop that in also.

Okay, I got everything done, and it works great!


Here's the reason I was asking about the extra slide. I performed the chipswitch mod to get the extra channels. I removed the D2824 PLL and replaced it with the D2816 PLL. Pulling pin 9 low gives 27.420-27.860, pulling pin 9 high gives 26.510-26.950. I needed to make up for the 5kc difference, that's part of the reason why I asked about the clarifier mod.

Now, my next question (I'm not going to make another thread, since this is related to this thread), is there a way to shift the 5kc without modding the clarifier? Anything I can do to the PLL circuit to make it shift the 5kc by using a switch? Just curious, if there isn't any way, I'll just dial it with the clarifier.

Regards,
Rick (Triple 7)

The easy way is to change the xtal (X1) to a 10.240 as the one fitted is 10.2417, you will need to realign L15, L16, and L17.

Have you try using Pin 20 as this is the divide by 5KHz pin.

If the radio was mine, I would change the PLL to a MC145106, a lot of work, but something to do in your spare time.

I have lot of project like this, I am just modifying a Galaxy DX99V to 40 meters at the moment.
I am looking for a front for a Galaxy DX93T but with no look.

I did swap out that 10.2417 Xtal for a 10.240, and changed the varicap, works real good, although there is a slight drift on SSB, nothing real bad, however.

I did notice that pin 20 is the 5/10kc offset pin, do I need to tie that high to get the 10kc offset? It's tied low currently. If I need to tie high, what pin do I need to tie it to on the PLL for the voltage needed?

I'll gladly try the MC145106 PLL if I can get some instructions on how to do it, I love projects such as these. I don't mind making a seperate board or whatever I need to do, I have the tools to do so.

I do have a used (good) MB8719 PLL, would this PLL work for a possible swap? Just curious...

Thank you VERY much for your time, I appreciate it no end, as I know you are busy.

Regards,
Rick (Triple 7)