Yaesu FT-767GX backup battery

Discussion in 'General Technical Questions and Answers' started by N5JRG, Jul 28, 2009.

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  1. N5JRG

    N5JRG Ham Member

    When my Yaesu 767GX with 2m module started topping out at 146.00 Mhz, I pulled out my tech supplement and found that this meant the lithium backup battery was gone (the unit also would not retain memories). With the help of a friend (and the schematic) we managed to locate the battery, a CR2025 button battery, in the tuner section. Getting it out was tough - it was held on the board by a thin strip of metal about 4mm wide (the + contact) and it appeared to be glued to the battery. We had to scrape the strip off with a razorblade, only to realize the bottom contact (- contact) was a strip also. The old battery is out and the strips are intact, if a little bent. My question is: how to get the new battery to stay in place with these bent/deformed strips. One suggestion was to solder wires to the strips and use an insulated battery holder for the CR2025, but I'd like to hear other suggestions. Anybody?
     
  2. KC8VWM

    KC8VWM Ham Member

    One approach is to install a AA battery holder inside the rig in a convenient location (outside the rig may be a better approach) and wire it to the existing CR2025 button battery terminals.

    Then you can use regular AA batteries for the memory backup instead.

    IE.

    CR2025 = 3.0 volts VDC

    2 x 1.5 VDC AA cells = 3.0 VDC

    Hardware required:

    [​IMG]

    Costs should be around .59 cents.


    Option # 2

    Install a new one of these (through hole mount type) "on top" of the old one:

    [​IMG]

    Hope that helps.

    My Best.
     
  3. N5JRG

    N5JRG Ham Member

    Thanks! I'll recheck the space limitations inside the rig and decide which holder would work better and go from there.
     
  4. W9GB

    W9GB Ham Member

    From your description, you don't have much bench experience in radio or electronics repair -- not aware of solder tab lithium coin cells. You have to desolder (using solder wick, etc.) these tabs from the radio control board!!

    Major Japanese mfg used lithium coin cells ("CR") with solder tabs (what you refer to as strips) in their radios -- since many were designed for mobile operaiton (optional mounting brackets, etc.) Batteries in radio with spring based battery holders -- do not work well in mobile radios.
    You hit bump in road, battery drops out -- your radio goes dead!.

    TAKE your solder tabs that you tried to strip off the coin cell to:
    Your national chain Batteries Plus retailer
    http://www.batteriesplus.com/

    OR .. mail order from Batteries America
    http://www.batteriesamerica.com/hamradio.htm

    They will sell you a FRESH battery and "spot weld" the proper tabs so that you can solder that battery (through hole) back on the processor control board. WATCH for proper (+) and (-) orientation or you can damage that unobtainium IC processor part on the control board!
    Hopefully you did not damage your PC board or copper traces!

    w9gb
     
    Last edited: Jul 29, 2009
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