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Easy fixes for slow to start, flickering or faulty fluorescent tubes

This article will help you fix any problems with your tubes.

The fluorescent tube won’t turn on (and isn’t buzzing).
It takes the tube a while to heat up so it can be used.
The tube's middle won't light, but the ends will.
The tube flickers constantly on and off

We will tell you the cause and how to fix it. These are the best ways to get the most from your fluorescent light.

The fluorescent tube won’t turn on
Possible causes
A tripped or blown fuse can cause no electrical power.
Dead or dying ballast
A dead starter
A dead bulb
Verify the power supply to your bulb

First, make sure the fuse is not tripping the power supply. This is a common occurrence. If more than one light trips, you should check that they all work.

Check the tube
Turn off the power switch for the bulb
Why not buy a new moonlight lamp instead go to and buy one.
Rotate the tube 90° until it stops turning. Slide the tube down
Examine both ends for darkened glass. If you see darkened glass at both ends of the tube, it is either damaged or very near the end. It will need to be replaced.
If the color of the bulb is not affecting your vision, you can try it in another fitting to check if it lights.
The bulb must be replaced if it does not light. If it does not light, the problem is most likely with the starter.
Starters: Checking and fixing
A starter is a small box in the light fitting which the tube sits next to.
The function of that starter, as the name suggests, is to feed enough energy into the tube so it lights it up.
Starters are only found in fittings that are 15 years old or older.
They cost as little as 20p - the easiest way to test a starter is to buy a new one and replace the old one.
How to replace and find your starter
If the starter is not visible, remove the tube. Sometimes starters are located underneath the tube. However, if the fitting seems modern, you might be searching for something that isn't there.
Turn off the light switch. Remove the starter by gently pressing it in and twisting to the left.
Replace the starter to see if it works.
Ballast checks and repairs
A ballast gives a bulb enough voltage to start it, but then limits the amount of current going to the bulb, enabling the bulb to give off a steady light.
A giveaway that a ballast isn't working properly is a buzzing sound coming from the bulb.
If you have more than one bulb in a fitting and all the bulbs are flickering or out then it's highly likely to be the ballast.
How to check the ballast
Turn off the light source at the switch, and then turn off power via the circuit breaker.
The tube should be removed from the fixture.
You will find a ballast cover. Remove the cover and inspect the ballast.
First, make sure all wires are correctly connected. If they are not, the problem will be with the ballast.
Ballasts come as a variety of sizes and shapes. If you need to purchase a new ballast, make sure you check the dimensions before you buy online. Or, bring your old ballast into the light shop.
A wiring diagram is usually found on your ballast (or in the box). This will help you identify which wires are where when replacing it. The ballast wires are usually coloured red, white and blue. They will match the fitting's colours.
YouTube has many videos that show how to safely change a ballast . This is one of our favorite YouTube videos for changing a T8 Ballast.

There are many types of ballasts and different instructions for how to change them. Ballast replacement can cause electrocution. If you aren't sure, ask an electrician for help. Use caution when using your fluorescent light.

You can also identify and fix other problems with the checks mentioned above
The tube's middle won't light, but the ends will.
Check out the starter
The tube flickers constantly on and off
Check out the starter
Make sure you check the ballast
Make sure the lamp that you have used in the fitting fits correctly
It takes the tube a while to heat up so it can be used.
Check out the starter
Additional resources
Follow the links to buy lighting products online:
Starter switches
Emergency combination ballasts – Normal high frequency ballasts with an emergency backup feature for fluorescent lamps that can be used in conjunction with an emergency battery.
Electronic HID ballasts To operate high intensity discharge lamps with flicker-free start (HID), e.g. Metal Halide lamps.
HF ballasts High frequency ballasts to run a fluorescent light bulb (turn on, turn off without flickering).