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Kenwood TM-241a Backup Battery Replacement

Was du brauchst

  1. Kenwood TM-241a Backup Battery Replacement, Main body: Schritt 1, Bild 1 von 3 Kenwood TM-241a Backup Battery Replacement, Main body: Schritt 1, Bild 2 von 3 Kenwood TM-241a Backup Battery Replacement, Main body: Schritt 1, Bild 3 von 3
    • Push down on the tab that locks the power connection together, and slide the two connectors apart.

    • Unscrew the antenna downlead from the antenna pigtail coming out of the radio, and pull the two apart.

    • Unscrew the microphone connector from the front panel of the radio, and pull it out.

  2. Kenwood TM-241a Backup Battery Replacement: Schritt 2, Bild 1 von 2 Kenwood TM-241a Backup Battery Replacement: Schritt 2, Bild 2 von 2
    • Using a #1 phillips screwdriver, remove the two screws that secure the top cover to the radio.

    • Do the same to the two screws on the bottom.

  3. Kenwood TM-241a Backup Battery Replacement: Schritt 3, Bild 1 von 3 Kenwood TM-241a Backup Battery Replacement: Schritt 3, Bild 2 von 3 Kenwood TM-241a Backup Battery Replacement: Schritt 3, Bild 3 von 3
    • There are two tabs that sit underneath the sides of the face plate. They have a tendency to break out the plastic over top of them while removing the covers. To help prevent this, push inward on the side of the cover, just behind the face plate as you take off the covers.

    • Lift up on the rear of the top cover, and slide it towards the back of the radio to disengage the three tabs at the front.

    • Repeat for the bottom cover of the radio.

  4. Kenwood TM-241a Backup Battery Replacement, Front Panel Assembly: Schritt 4, Bild 1 von 3 Kenwood TM-241a Backup Battery Replacement, Front Panel Assembly: Schritt 4, Bild 2 von 3 Kenwood TM-241a Backup Battery Replacement, Front Panel Assembly: Schritt 4, Bild 3 von 3
    • On the left side of the screen, gently pull on the tuning knob, separating it from the radio.

    • The upper knob on the right is the volume. Gently pull it away from the radio to remove it.

    • The lower knob on the right is the squelch knob. Remove it in the same way as the other two knobs.

    • Set the three knobs aside, so they can be put back on later.

    • The volume and the squelch knob are the same part and can be interchanged.

  5. Kenwood TM-241a Backup Battery Replacement: Schritt 5, Bild 1 von 2 Kenwood TM-241a Backup Battery Replacement: Schritt 5, Bild 2 von 2
    • Below where the tuning knob was, there is a 7/16" nut that helps to secure the face plate to the radio. This needs to be removed to allow the face plate to be taken off.

    • Behind the nut is a small washer. Be sure to pull it off as well and set the two aside so they do not get lost.

  6. Kenwood TM-241a Backup Battery Replacement: Schritt 6, Bild 1 von 1
    • Below the jack for the microphone, there is a nut. This is not a standard hex headed nut. It has four notches around the edge of the nut. A pair of snap ring pliers works well to engage the notches, allowing you to remove the nut.

  7. Kenwood TM-241a Backup Battery Replacement: Schritt 7, Bild 1 von 3 Kenwood TM-241a Backup Battery Replacement: Schritt 7, Bild 2 von 3 Kenwood TM-241a Backup Battery Replacement: Schritt 7, Bild 3 von 3
    • There is a screw on each of the four sides (top, bottom, and each side) of the face plate. Removing these screws will allow the face plate to be removed from the radio body.

    • There are two types of screws used in this step. The screws on the top and bottom are different from the screws from the sides. Note which style of screw is used on each side.

  8. Kenwood TM-241a Backup Battery Replacement: Schritt 8, Bild 1 von 2 Kenwood TM-241a Backup Battery Replacement: Schritt 8, Bild 2 von 2
    • The face plate can now be removed from the body of the radio. Gently pull on the face plate to separate it from the radio. It might require a little bit of wiggling to remove.

    • Be careful when removing the front panel. The connectors inside are known to have weak solder joints, and it is possible to pull them off of the circuit board.

  9. Kenwood TM-241a Backup Battery Replacement, Control Board: Schritt 9, Bild 1 von 1
    • On the right side of the board, there is a screw that goes through a transistor, that secures the control board to the radio. Remove this screw, and set aside.

    • Remove the screw on the left that holds the board to the radio. Set it aside.

    • The two screws that are removed during this step are not the same. Note which screw comes from which side. The screw with the tapered head goes on the left. The screw with a flat mounting surface goes on the right.

  10. Kenwood TM-241a Backup Battery Replacement: Schritt 10, Bild 1 von 2 Kenwood TM-241a Backup Battery Replacement: Schritt 10, Bild 2 von 2
    • Pull the control board away from the radio body. It will be slightly more stubborn than the face plate was.

    • There are two connectors that have to be disconnected. Pull hard enough to separate the connectors, but not hard enough to pull them off of the circuit board.

  11. Kenwood TM-241a Backup Battery Replacement, Backup Battery: Schritt 11, Bild 1 von 1
    • Using a voltmeter, measure the voltage of the battery. The voltage should be around 3.0 volts.

  12. Kenwood TM-241a Backup Battery Replacement: Schritt 12, Bild 1 von 3 Kenwood TM-241a Backup Battery Replacement: Schritt 12, Bild 2 von 3 Kenwood TM-241a Backup Battery Replacement: Schritt 12, Bild 3 von 3
    • If the voltage is below about 2.75 volts, the battery will have to be removed. Using a soldering iron, melt the solder holding one of the solder tabs to the board. While the solder is molten, pull the solder tab away from the board with a pair of tweezers.

    • Repeat the procedure for the other solder tab.

    • The battery is held to the board with a piece of double sided fabric tape. This will probably rip apart when you pull the battery off.

    • It would be a good idea to put shrink tubing around the new battery to ensure it doesn't short out to anything on the control board.

  13. Kenwood TM-241a Backup Battery Replacement: Schritt 13, Bild 1 von 2 Kenwood TM-241a Backup Battery Replacement: Schritt 13, Bild 2 von 2
    • Put a little liquid flux on the solder that was left on the solder pads.

    • Using some desoldering braid, sometimes also called desoldering wick, remove the old solder.

    • Using isopropyl alcohol and an acid brush, clean the flux residue off the board.

  14. Kenwood TM-241a Backup Battery Replacement: Schritt 14, Bild 1 von 2 Kenwood TM-241a Backup Battery Replacement: Schritt 14, Bild 2 von 2
    • Using more flux, and some new solder, solder the new battery onto the board.

    • Make sure that the proper polarity is observed.

Abschluss

To reassemble your device, follow these instructions in reverse order, beginning with step 9.

6 weitere Nutzer:innen haben diese Anleitung absolviert.

Josh

Mitglied seit: 03/22/13

707 Reputation

4 Anleitungen geschrieben

4 Kommentare

Great info thanks for the post !!! On mine I wired in a button battery holder. Connect the wires, observing polarity, to a Radio Shack (RS 270-430) button battery holder. Insulate the positive terminal and negitive with either heat shrink tubing or liquid electrical tape. The single tab is the negative. Mount the battery holder on top of the metal can located in the center of the transceiver with a double-sided sticky pad, making sure not to cover the adjustment openings. Install a CR2032 3 Volt Lithium battery in the holder.

erichraven - Antwort

Good HOWTO with photo’s how to replace the battery.

After 25 years of gathering dust my TM531’s memory works again.

Thanks!

frank.hartendorp - Antwort

Great replacement guide. Polarity of the battery is negative “up” in the picture with the meter measuring the old battery.

Thomas Fry - Antwort

Good directions thank you!

Problem is , battery 3.3 volts , memory messed up , erased old memory first . Bad radio , I guess

rch9426 - Antwort

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