President Lincoln II V3 Schematics

Well all around the world the technicians have been writing many words about how they change the Lincoln II for the better with the schematics. “I’d make it 100w” says one person and another will make it “Like a Yaesu on audio” and other such quotes and ideas that frankly you wonder why they do not work for one of the makers of the radios as sure the skill, knowledge and general aptitude for changing the radios will be an asset to the companies.


So with this in mind below is the details of the radio. It is the v3 with the board date 20140304

Lincoln II V3 Schematic

Remember when your radio is in pieces, not working like the Yaesu you intended and when all else fails there is NO warranty, NO right of repair.. So get set and go buy another V3 and try again

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6 thoughts on “President Lincoln II V3 Schematics

  1. Ah Ha,did find something that does point to why the fm may sound a little bit dull\no punch,really like to scope on on bench to confirm but it looks like there is no fm clipping action after U500,there def a automatic microphone gain control via Q512\513,think that’s a typo on schematic AM_ANL should be AM_AMC,dont think ANL circuit would not be there!
    Unless U500 being driven into a square wave to achieve clipping but it does not look like that as U500 low pass filter prob around 3khz( dont quote me)Can anyone confirm?
    .For TECHs ONLY with proper test equipment only! try this experiment only,remove R504,fit two !N4148 back to back (K to K)with a resistor say 68k at the middle of Kathode\Kathode of diodes other end of resistor tied to tx 8V,the Anodes of diode go to R507\C526 and other Anode of diode to R504\Q500 collector\W500 5K resistor point.
    You may have to increase value of C526 to get more Audio drive,The 68k resistor controls the bias switch on\clipping,this circuit does require suitable amount of audio drive from microphone circuit to work into clipping,adjust W500 for 2-2.2khz peak deviation,check total dev with CTCSS mid tone on max 2.5Khz max,use engineering mode to adjust DCS\CTSS deviation to 300-350hz DEV max LP filter on dev meter,DO this only if you know what your doing you Have been warned!
    The clipping circuit is the same as used in SS3900 and various President chasis for ref R75,D21,32,RV10 (should be 5k LIN to work correctly hint) if you want to look at circuit diagram to copy\try on usual places on net.
    Some experiment in U500 A&B with caps may provide better transmit audio curve?
    Some more studying required.

    Sorry if typo’s!
    Im tired and knackered,brains fryed doing schematics diagrams all day at work on PC!
    The above is experiment mod for Professional radio engineers only,I cannot stress this and may result in damage\warranty issues and as of yet hasnt been tried on radio! if you dont know what your doing or understand,DONT Touch it,Im not responsible ,I havnt got the time anymore to do a lot of mod work lately so thought Id let some of the other Pro Engineers have a go,you know who you are and Simon knows the ones too,just like to see the best out of this radio for the usersat te end of the day!


  2. Brill!,will study closely now,wonder if i can make it sound like a Kenwood,Yaesu and a Icom? lol
    will get diagrams blown up to A3 for ease of old Tech’s eyes,Thanks Simon saves me a job getting them thru normal channels.
    If I find anything interesting will let you know Si,Im sure someone mentioned they wanted punchy motorola fm without the out power microphone trick!
    Thanks again Simon!


  3. Hi Simon, I am fine. Only conditions are quite bad these days, specially with my low located antenna between the houses it is difficult to work several distant stations. Maybe one day I will hear you on some freq. and make a contact.


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