How To Fix A Broken Neon Sign?
Introduction
The neon sign is an essential part of art, culture and history. The neon tube is the most common type of neon sign. It emits light when the gas inside is discharged into the vacuum tube. The neon lamp can be made of different materials, such as glass, quartz or plastic tubes.
This article will teach you how to fix neon signs at home. It will also show you how to replace broken parts in your neon sign and how to take care of your signs for better performance and longer life.
Table of Contents
Principle and manufacturing of Glass Neon Light
Glass neon light is a common commercial lighting device. Its principle is to use the gas discharge phenomenon generated by the electric shock of neon (or other inert gases) to emit light. Glass neon lights are usually made of a glass tube, the interior of which is filled with neon and other inert gases.
The manufacture of glass neon lights requires first making a hollow glass tube and then coating the inside with phosphor. Next, fill the tube with neon and other inert gases (such as helium), add electrodes to one end of the tube, and connect the other end to the power supply with a wire. The current passes through the air to ionize the neon gas and produce a blue glow. The presence of phosphor can convert this blue light into other colors, such as red or green.
A few things you need to know about how neon signs work.
1. Most neon lamps use cold cathode glow discharge.
When the cold cathode is working, the whole lamp basically does not generate heat, and the efficiency of converting electrical energy into light energy is high. Its life is much longer than that of ordinary fluorescent lamps. For example, the quality can be guaranteed from materials, processing to installation. The service life of neon tubes can be as high as 20,000h–30,000h. Another great advantage of cold cathode discharge lamps is that the number of switching does not basically affect their life, so they are particularly suitable for advertising lamps that need to be frequently switched.
2. It relies on positive ions to bombard the cathode to make the cathode emit secondary electrons to maintain discharge, so a certain cathode potential drop is required to provide energy for positive ion acceleration. The cathode potential drop is about 100V-200V.
3. In order to ensure that it can discharge in the normal glow discharge area and no large cathode sputtering occurs during operation, the cathode needs to have a large enough area, otherwise the cathode current density will be too large due to the flow of large current, which will increase the cathode potential drop, turn into abnormal glow discharge, increase cathode sputtering and shorten the life of the lamp.
4. If possible, the neon tube should be as long as possible, with a smaller inner diameter, and the proportion of the positive column area voltage drop in the total voltage drop of the tube should be increased as much as possible to improve the light efficiency.
5. In order to ignite the neon tube smoothly and work stably at a lower voltage, a high-voltage transformer must be equipped (mostly leakage magnetic type, but because it is bulky and consumes a lot of power, it will gradually be replaced by electronic type) and reasonably matched to save engineering costs.
6. Neon lamps use alternating current to work, so the two electrodes alternate as cathodes and anodes, and the regional distribution of their glow discharge also alternates in order. Due to the visual persistence of people, you can see that the glow is evenly distributed throughout the tube, and the luminous effect is much better than using direct current. Therefore, the two electrodes should be as consistent as possible from materials to processing.
7. Because neon lamps are vacuum electric light sources, the entire production process needs to pay attention to vacuum hygiene. Strictly follow the requirements of electric vacuum technology for materials and production to ensure quality.
Maintenance of Glass Neon lights
Maintenance of neon lights mainly includes checking for gas leaks, replacing failed electrodes or lamp tubes, adjusting the power supply voltage, etc. When repairing, the cause of the failure must be determined first, and it may be necessary to replace the damaged part, refill the gas, and perform welding and sealing.
Common faults and repair methods of glass neon lights
1. Fault phenomenon: The lamp does not light up after the power is turned on
Cause of the fault:
The power supply is out or the power supply network is faulty. The power fuse is blown or the switch is in poor contact. The high-voltage side of the transformer is short-circuited or disconnected. A bad section of the lamp tube is leaking.
Repair method:
Use a test pen to measure the power supply voltage to determine whether the network is out of power or has a fault, then find the cause from the network and repair it to make the power supply normal.
Check whether the power fuse is blown. If the fuse is intact, use a multimeter to check whether the contact is good after the switch is closed when the switch power is disconnected. If the switch is damaged, replace it.
When the power is disconnected, use the multimeter resistance range to detect whether the high-voltage side of the neon lamp transformer is short-circuited, or whether there is a short circuit at a small resistance. If the transformer is damaged, rewind the high-voltage side coil or replace the transformer.
If a section of the lamp tube is not lit and the power supply voltage is normal, disconnect the power supply and replace the lamp tube.
Tips:
1. All neon tubes do not light up: Because neon lights generally supply power to multiple high-voltage transformers, if all neon tubes do not light up, the possibility of transformer failure is unlikely. The main reason is the power supply problem. You should check whether the power supply is normal and whether the wiring is burnt.
If a single transformer supplies power, check the transformer by inserting a milliammeter in series with its secondary winding. If there is no current during the inspection, it indicates that the winding has been blown; if the current is much smaller than the normal operating current during the secondary short circuit, it indicates that there is a fault and the transformer should be repaired or replaced.
2. Some neon light tubes do not light up: the possible reasons for this failure are as follows:
(1) Automatic switch.
(2) The high-voltage connection is burned out.
(3) The neon tube is burned out: You can use a high-frequency spark leak detector to check the lamp tube of the unlit unit segment by segment. The method is to bring the wire end of the leak detector close to the glass of the lamp tube. If it emits purple linear sparks into the tube or completely If it does not emit light, the lamp is damaged.
It should be noted that if the service life of the non-lit neon lamp is close to or exceeds, it is not suitable to mix old and new lamps. It is better to replace all new lamps. Mixing old and new lamps will accelerate the aging and failure of the old lamps, resulting in more losses than gains.
2. Fault phenomenon: temperature is too high
Cause of the fault:
The leakage transformer is damp and has poor performance. The leakage transformer exceeds the rated load. There is a turn-to-turn short circuit on the high-voltage side of the leakage transformer.
Repair method:
Use a multimeter to measure the power supply voltage. If it is more than 10% lower than 220V, find the reason for the low power supply voltage on the Internet and deal with it. Replace a larger leakage transformer.
Disconnect the neon light power supply, remove the leakage transformer and dry it. In special cases, if the transformer temperature is too high, try to dissipate the heat or use an exhaust fan to dissipate the heat. Check the neon light transformer and eliminate conductive contacts.
3. Fault phenomenon: flashing but not bright
Cause of the fault:
The power supply voltage is too low to start. The leakage transformer is overloaded. There is a turn-to-turn short circuit on the high-voltage side of the leakage transformer.
Repair method:
Use the resistance range of the multimeter to check whether the resistance on the high-voltage side of the leakage transformer is smaller than normal when the power is disconnected, and determine whether the transformer is short-circuited. If the transformer is short-circuited, it should be rewound or replaced.
4. Fault phenomenon: Blackening near the neon tube
Cause of the fault:
The power supply voltage has been too high for a long time. The tube has been used for too long and aged.
Repair method:
Use a multimeter to measure whether the power supply voltage is too high. If it is too high, find the cause from the circuit and try to reduce the power supply voltage. If it cannot be reduced, you can also use a larger power special transformer to reduce the power supply voltage to a normal value before using it. If the tube has been used for too long and aged, replace it with a new neon tube.
5. Fault phenomenon: Blackening near the neon light
In special cases, the transformer temperature is too high, and you need to find a way to dissipate the heat or use an exhaust fan to dissipate the heat.
Precautions for repairing glass neon lights
Repairing or restoring old neon signs, or maintaining neon signs that have just been made, is often not a pleasant job. The work involved is far from pleasing to the eye: a few quick bends, a few welds, and a re-inflation.
There is always disassembly, cleaning, scraping, glass tube cracking, shattering, smoke and fire, and even more trouble in actual work. Here are a few precautions to help you reduce the trouble.
1. Preparation for repairing neon. In order to make the repair process easier and more economical.
The first step is to copy the surviving lamp sample. Because the original sample or design economy cannot be found (if it can be found, it will be even better), if the only part of the repair sign is also broken. You will regret that you should have traced a sample.
Now start making the sample, just trace the lamp onto the bending material or pattern paper. Trace close to the lamp, so that the original appearance can be best shown. Then fill in the blanks as much as possible, such as broken or missing parts.
A photo of the original sign, or a bit of background paint, and vinyl film can help fill in the gaps. Otherwise, you’ll have to guess as closely as possible what the sign looked like when it was designed, based on the lettering or its artistic style.
2. Clean up the impurities and determine the difficulty of the repair.
Once the sample is drawn, it’s time to scrape off the old insulation and cover the paint. This step serves two purposes.
First, it helps determine whether the component is a mercury tube or a neon tube (of course, only a very few very old neon lamps used mercury as the medium for the gas discharge in the bulb, and modern neon lamps do not contain mercury), and it helps reduce the harmful fumes generated in the workshop during the heating and processing of the lamp. Of course, it is also important to fill the lamp with the original gas to keep it from glowing, but mercury lamps require special considerations.
Second, if mercury is found in the tube or at the poles, you have to decide whether the risk of repair is worth it. The vapors produced by the heating of mercury can cause great harm to health, and in some cases even involve personal injury, which leads to insurance liability issues. Nowadays, it is best to remove and save the impure mercury and then rebuild the entire lamp to avoid health hazards and potential liability. This step also includes wiping the lamp, which is to prevent interfering particles from entering the lamp during the repair process.
3. Check the vacuum and repair the lamp.
This step can also be reversed from the previous step. It is mainly to check the vacuum of the lamp. Of course, there is no need to check when there is an obvious crack or the lamp is not coated. If this step is omitted, it may damage the lamp coating. Therefore, it is very important to use a lamp tester or spark coil to determine whether the lamp is vacuum.
If the lamp lights during the test, it is vacuum, and cutting the lamp at this time will cause air to rush in, destroying the intact lamp, so you have to rebuild the entire lamp.
To slow down the air rushing into the vacuum lamp, use a handheld blowtorch to heat the top of the sealed tube. Usually the top will crack, and hold it tightly with your fingers when it starts to cool to slow down the air entering the lamp. The solid tube after annealing may not crack. At this time, it can be gently peeled off.
If these methods do not work, it is necessary to heat the seal at one end with a hand-held blowtorch, and then use ice cubes to increase the stress if the ice cubes are considered sufficient to break the seal. However, protective goggles must be worn to prevent the glass from bursting in all directions if it breaks. It seems that the decision has been made to repair it.
Old tube coatings sometimes emit different light depths when used in conjunction with new tube coatings. This is because the performance of phosphors gradually decreases over time. If the tube is old, it is recommended that the customer re-tube it. If the repair is part of a large project, it is safer to inform the customer that the old tube may emit a deviation in color. This is easier to solve the problem of collecting the payment.
Typical uncoated glass also has such problems. It may be difficult to match the color appropriately. Also, either use the same tube diameter or risk different light output. Smaller diameter tubes will emit more dazzling and brighter light than larger tubes, so mismatched tube diameters will affect the relative brightness of the repair.
4. Blown glass tubes to deal with unexpected events.
Then finally comes the process called glass blowing. First, tap the tube gently, then gently blow out the loose phosphor coating and other unwanted particles.
Some people even go a step further and wash the tube with water. This is a good idea. But with water trapped inside the tube, the loose powder coating looks like a filth, which is not pleasant.
Now, consider that repairing a tube means you are repairing someone else’s glasswork, which sometimes makes the job easier than your own, and sometimes it’s the other way around.
When it comes to the latter, be wary of the stress hidden in the glass tube. You can’t see it with your eyes, but it’s there, waiting to pounce like an angry snake. When a long arc of cracks creeps along the wall of a tube due to stress, jump ahead and heat a small ring on the tube. Once it melts, gently tighten the tube and let it cool completely. If the crack continues along the arc, it will stop at this point. The tube can be cut here and the repair is complete. Occasionally, you will come across a set that contains so much strained glass tubing that you wonder why the tube didn’t explode long ago.
At this point, rather than fighting through endless cracks, chips and breaks, it is better to call the customer and explain why a complete and thorough re-production is imminent. Otherwise, you risk turning a 2-hour repair job into a large, all-day project.
How to do it step by step？
Step 1 – Turn off, unplug and safely remove your neon
Turning off and unplugging a neon sign is the first thing you should do if it is giving you trouble. There is a very good risk that you will be electrocuted if you don’t do this before working on the sign. You can remove the sign from its housing without risk after it has been powered down and unplugged.
Step 2 – You Can Start troubleshooting
You have the right tools in hand and you’re ready to get started. The initial step is to look for any evident problems that are simple to resolve.
Look at your sign’s glass tube first. If it is damaged or cracked you should replace the tube right away since if used incorrectly, it could harm you or someone else.
Next, look for any hardware—such as loose screws or other pieces of hardware—that might be harming your neon sign. These are the typical issues that can occur when neon signs are used.
- Burned Out Lights – Over time, some parts or sections of a neon sign can fuse. This is a common occurrence in light fixtures as well.
- Sections Stop Working – Sometimes some sections of the light or sign stop operating
- Broken Transformer – The transformers on some of the neon signs may malfunction or be damaged.
Step 3 – Broken Neon Light Glass Repair
A broken neon light is a problem that can be easily solved. If you have a broken neon light, you can fix it yourself with a few simple steps.
- Get a replacement piece of glass for the broken neon
- Remove any screws holding down your old glass piece with a screwdriver or drill bit.
- Once all screws have been removed, lift out your old glass piece and replace it with new one by sliding it into place in its original spot
- Push out any epoxy bonds holding them together so they stay in place while they cure over time without falling out again once cured properly
How to Safely Repair a Neon Light Sign?
Before beginning any repairs on your neon sign system, turn off power at the circuit breaker panel and disconnect all power from the sign’s electrical supply box by removing fuses or circuit breakers from their slots in the panel box. This will ensure that no electricity flows through any part of your system while working on it so you don’t risk being shocked by stray voltage or damaged equipment during repairs.
When inspecting the casing, if the exterior is corrupted due to long-term use, you can try wiping or processing with professional surface finishing.
How to Troubleshoot a Problematic Neon Sign?
If your neon sign is not working, you may be able to troubleshoot the problem yourself with these steps:
Flickering
Neon sign flickering can be a common problem with many signs, especially if they are older. The most likely cause of this flickering is a loose connection somewhere in the sign’s wiring. To fix this, you’ll need to know how to identify which parts of the sign are connected by wires and which are not. Then, you can look for loose connections in those areas and repair them using wire nuts or electrical tape.
Turns On Then Turns Off
If your neon sign comes on for a brief period of time before turning off again, try these troubleshooting steps.
- Check your circuit breaker first. If it has been tripped, reset it to check if the issue still exists.
- If that doesn’t work, try disconnecting the cord from the outlet and then replugging it; this may be sufficient to restart the system and restore normal operation.
- You might need to replace your fuse or circuit breaker if these methods don’t resolve the problem.
Dim Letters
If the lights on your neon sign are dull, the tubes are probably not getting enough energy.
By using a voltmeter to test it, first make sure that your power source is operational. You should inspect your transformer if it is operating. The transformer could need to be replaced or there may be a problem with it.
You must check the resistance of each tube in an antique neon sign if there isn’t a transformer attached to it to ensure that the tubes are all reading properly. The reason why your sign is dimming could be because one or more of the tubes have higher resistance than the rest.
Does Not Turn On
Check these things if your neon sign doesn’t light up.
First, confirm that your sign is powered by the appropriate type of electricity. If you try to use a low voltage light bulb to power a neon sign, it might not work because neon signs need a very high voltage of energy. Moreover, you should confirm that the light bulb is functioning properly and has not burned out.
The transformer may have failed or the neon tube may have broken if you’ve checked those things yet your sign isn’t working. To try again in this situation, you’ll need to replace them both.
Are LED Neon Signs Repairable?
LED neon signs can indeed be repaired. An LED sign’s parts are made up of numerous straightforward, modular components that are simple to replace if something goes wrong, which is why they are so simple to fix and maintain.
Short-circuit
If your neon sign is short-circuiting, the first step is to trace the wires back to their source. The result will be either a transformer (which you can buy at a hardware store) or a circuit board. If it’s a circuit board, check for blown fuses and replace them with new ones if necessary. Then, check all of the capacitors on the board and replace any that are bulging or leaking.
If this doesn’t solve your problem, you’ll need to find out where in the circuit something has failed—either in an individual bulb or in the power supply itself. It’s usually easier to tell by looking at which lights are flickering or dimming than by trying to diagnose each light individually.
Loose Connections
You have a few options if your neon sign is loose. Tighten the connections first, and then check to see if the issue is resolved.
If it doesn’t work, you might need to have parts of the neon sign’s cables or joints replaced. Any burned-out or flickering bulbs may also need to be replaced.
It’s time to hire a pro if none of these solutions work for you.
Faulty Transformers
Any neon sign’s transformer is its most crucial component, and if it malfunctions, the sign as a whole will stop working. Transforming the mains voltage into a low voltage allows neon tubes to shine. Your neon sign’s malfunctioning transformer is likely to be the reason of it flickering or not shining at all.
The transformer must be removed from its location and replaced by removing the screws keeping it in place. After that, screw the new transformer firmly into place and connect it.
