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TUCoPS :: Radio :: ft211rh2.txt

Yaesu FT-211RH mods


    3.The only indication of low power operation is in the memory mode.
      A "C" will appear in the upper left corner of the display (where
      the primary "P" used to be). The bargraph will always read 100%.

    4.The band scan is now even more useless. The uP will painfully 
      count from 50 to 300 MHz.

    I have been able to modify my FT-211RH to scan at about 10 chan/sec
    by speeding up the uP clock. This also speeds up every other uP
    function by x5, so you have to be fast on the "F" key. No squelch
    sensitivity or synthesizer lock-up problems have been encountered
    with this modification while scanning.

    Basically, I replaced the 800 KHz ceramic resonater (pn CSB800K)
    with a Radio Shack 3.58 MHz color burst crystal. The resonater is 
    located on a small (2.5 sq cm) sub-board that is stuck with double
    sided tape to the radio's processer board. This sub-board is actually
    an outboard clock for the uP. The schematic I got with the radio
    showed the uP's internal osc. being used - so I don't know if my
    version differs from newer radios. This mod works fine untill you
    turn the radio off and then back on again. A startup glitch then wipes 
    out all of the memories. To delay the oscillator start up, I added a
    220uF 10V electrolytic cap between the red wire on the sub-board
    and ground. Positive goes to the red wire. A convenient ground is the
    bare wire located diagonally across from the red wire (on the sub-bd).

    So far I have been unsuccessful with this mod on the FT-23R H-T.
    Since it uses the uP's on board osc, there seems to be no way to
    delay it's startup. Every time you turn on the power the uP resets.
    If anyone can solve this problem I would be very interested in 
    hearing from you!

    These are not intended to be step by step instructions. Also, you
    will want to have a service manual before you begin. If you're not
    familiar around surface mount components you may want to "learn"
    on something with cheaper consequences. Finally, don't adjust the
    VCO's unless you are familiar with how a synthesized radio
    works. Use your own judgement!
   /   Ken Gianino  
       WB0QNA        ** \

Note: I haven't tried this, proceed at your own risk. WA2ISE

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