The FT-2400 uses two replaceable bulbs you can swap yourself in about five minutes

The Yaesu FT-2400 has two light bulbs: one behind the display and one in the microphone connector area. Both are standard incandescent bulbs that burn out over time, especially if you leave the radio on for long periods. You do not need to send the radio to a technician — you can replace them with basic tools and a steady hand.

The display bulb is the one you will notice first when it fails, since the frequency and mode readout will dim or go dark. The microphone illumination bulb is less critical but makes the mic easier to use in low light. Both replacements cost a few dollars and take just a few minutes.

Key Takeaways

  • The FT-2400 display bulb is a 12V incandescent type, typically a #44 or #47 bulb, available from electronics suppliers for under five dollars.
  • You will need a small Phillips head screwdriver and a small flashlight to see inside the radio during replacement.
  • The display bulb sits in a holder behind the LCD panel and twists out counterclockwise, then twists back in clockwise.
  • The microphone bulb is located near the microphone jack on the rear panel and follows the same twist-in, twist-out method.
  • Always unplug the radio from power and disconnect the microphone before opening the case to avoid accidental damage.

What bulbs the FT-2400 needs and where to find them

The display illumination bulb is a 12V incandescent lamp, most commonly a #44 or #47 bulb. These are standard automotive-style bulbs with a bayonet or twist-in base. You can order them from electronics suppliers like Mouser Electronics, DigiKey, or Amazon. A pack of five costs around three to eight dollars depending on the seller. Do not buy LED replacements unless you are certain they are rated for 12V DC — some LED bulbs designed for 12V automotive use will work, but others are designed for AC and will not light properly.

The microphone illumination bulb is the same type and voltage. If both bulbs are burned out, you can buy a single pack and use two from it. Keep one or two spares in your radio kit so you have a replacement ready if a bulb fails during an event or emergency.

How to access the display bulb

Unplug the FT-2400 from the power outlet and disconnect the microphone from the rear panel. Remove the four Phillips head screws on the top of the radio case — two near the front and two near the back. Gently lift the top cover off and set it aside. You will see the LCD display panel mounted to the main circuit board.

Behind the LCD panel, you will find a small cylindrical bulb holder. It is usually mounted vertically and glows when power is on. Reach behind the display and gently grasp the bulb holder. Turn it counterclockwise about a quarter turn until it stops, then pull it straight out. The bulb will come out with the holder. Unscrew the old bulb from the holder by turning it counterclockwise, then screw the new bulb in clockwise until it is snug. Do not force it — these bulbs are fragile.

Reinsert the bulb holder into its socket behind the display and turn it clockwise until it clicks or stops. The bulb should now be seated. Replace the top cover and tighten the four screws. Plug the radio back in and turn it on to confirm the display lights up.

How to access the microphone illumination bulb

The microphone bulb is easier to reach than the display bulb because it is on the rear panel. Unplug the radio and disconnect the microphone. Look at the rear panel near the microphone jack — you will see a small bulb holder, usually a plastic cylinder about half an inch long. It may be recessed slightly into the panel.

Reach around to the rear of the radio and gently grasp the bulb holder. Turn it counterclockwise about a quarter turn until it stops, then pull it straight out. Unscrew the old bulb and screw in the new one, then reinsert the holder and turn it clockwise until it seats. Reconnect the microphone and plug the radio back in. The microphone area should now light up when you transmit or when the radio is powered on, depending on your model year.

Tools and materials you will need

Gather these items before you start: a Phillips head screwdriver (size #2 is standard for the FT-2400), a small flashlight or headlamp to see inside the case, two replacement bulbs (12V #44 or #47), and a clean, flat work surface. A small bowl or cup is useful for holding the four screws so you do not lose them. Wear an anti-static wrist strap if you have one, though it is not strictly necessary for this task since you are only touching the bulb holders and not the main circuit board components.

Work in good lighting and take your time. If you rush and drop a screw inside the case, you will have to open it again to retrieve it. If a bulb breaks during removal, do not touch the glass fragments — dispose of them safely and use a new bulb.

Troubleshooting if the new bulb does not light

If you install a new bulb and it does not light, first confirm that the radio is powered on and that you are looking at the correct area. The display bulb should glow whenever the radio has power. The microphone bulb may only light during transmission or when a certain mode is active, depending on your FT-2400 version.

If the bulb still does not light, the bulb holder itself may be damaged or the socket may have a poor connection. Try removing the bulb holder again and reinserting it firmly, making sure it clicks or seats fully. If it still does not work, the socket may need replacement — this requires soldering and is beyond a simple bulb swap. Contact a Yaesu service center or an experienced radio technician if the holder is damaged.

If you installed an LED bulb and it does not light, the LED may not be compatible with the FT-2400's 12V DC power supply. Remove it and install a standard incandescent bulb instead.

Frequently Asked Questions

Can I use LED bulbs instead of incandescent ones?

Some 12V DC LED bulbs will work, but not all. LEDs designed for automotive use are usually safe, but LEDs made for AC power will not light. Stick with standard incandescent #44 or #47 bulbs unless you have confirmed that a specific LED is rated for 12V DC and fits the FT-2400 socket.

How often do the bulbs burn out?

Incandescent bulbs typically last 500 to 2,000 hours depending on how often you use the radio and how much heat builds up inside the case. If you use the FT-2400 daily for several hours, expect to replace the display bulb every one to two years. The microphone bulb usually lasts longer because it draws less current.

What if I drop a screw inside the case?

Do not panic. Open the case again and locate the screw using a flashlight. Use a magnetic screwdriver or a pair of tweezers to retrieve it. If you cannot reach it, gently tilt the radio to let the screw slide to an accessible area. Never shake the radio or turn it upside down without knowing where the screw is.

Do I need to recalibrate the radio after replacing a bulb?

No. Replacing a bulb does not affect any of the radio's settings, frequency memory, or calibration. The radio will work exactly as it did before once the new bulb is installed.

Where can I buy replacement bulbs if my local electronics store does not have them?

Mouser Electronics, DigiKey, and Amazon all stock #44 and #47 bulbs in packs. You can also contact Yaesu directly or check with local ham radio clubs — many members keep spare parts on hand and may have a bulb you can use immediately.