How to Fix Projector's Keystone Correction and Lens Focus?

May 19, 2020

How to Fix Projector's Keystone Correction and Lens Focus?

If you are an avid user of projectors, you might have encountered some focusing or keystone problems. Sometimes the focus feature is not working properly, it gets stuck or not really doing its job properly. The keystone feature sometimes stops working altogether or works faultily. These problems can hinder your projecting experience and can be very frustrating. Fortunately, this is a problem that can be easily fixed with a bit of knowledge. In this article, we will share some insight on some of the most common issues with the focus and keystone features of projectors. Let’s get started!

What Is Lens Focus?

Lens focus is a common feature that almost all projectors use to align the projected image on any surface. Most projectors have manual dials and knobs that can be turned to align the projected image. What happens is that the movement of the lens assembly allows the light beams to refract in a specific way, thus giving the user control of the projected image directly.

Why a Projector Lens Gets Stuck?

Some of the most common issues with lens focus occur because of some types of assembly issues or lack of proper maintenance. Foreign objects or substances can also embed themselves within the dials, knobs, and lens assembly, blocking them or causing resistance when moved.

What Is Keystone Correction?

Keystone correction is a standard feature that has become very common in most projectors over the past 30 years or so. The name keystone correction comes from the keystone effect. The feature corrects the keystone effect, which is the distortion of an image that is projected on an angled surface. Modern LCD projectors achieve this through digital means, by altering the scaling of electrical inputs through special algorithms before the inputs reach the liquid crystal display, thus allowing for the image to be corrected before reaching said angled surface.

Why the Keystone Correction Feature Doesn’t Work?

Keystone correction may stop working for several reasons. Some of the most common issues are:

  • Keystone button(s) is stuck
  • The angle of projected surface is unsuitable
  • Damage to the internal components
  • Damage of the projector LCD screen
  • Damage of the lens assembly
  • Electrical inputs not working properly

Most issues with keystone corrections will require professional help, this is due to the complex nature of the electronic components that allow such a feature to work effectively. Fortunately, sometimes the keystone button(s) may get stuck due to foreign substances or faulty assembly, or a problem with a faulty lens that can be easily replaced. All of these issues can be fixed at home with a few tools.

How to Fix the Lens Focus and Keystone Correction?

If your projectors lens or keystone features are stuck or can’t move, there are a few easy fixes that should be tried before any forms of disassembly. It is important that you don’t apply too much pressure or strength when trying these easy fixes, as you can end up with a broken or heavily damaged projector.

  • Apply slight pressure to the knobs and dials to see if they become unstuck
  • Apply slight pressure to the keystone correction button(s)
  • Try turning or pressing the button(s) slowly
  • Change the location of the projector
  • Change the surface in which you are projecting
If these easy fixes don’t seem to work, maybe it is time to dig a little deeper.

1. Understand your equipment

It is very important that you understand what is your projector model and manufacturer. This way you can check the manual or online information about your particular issue. In order to proceed towards more advanced fixes, it is imperative that you understand your equipment well.

2. Check the Keystone Correction Button(s)

The first thing to do is to check the keystone correction button(s). You do this by following a few simple steps:

  • Check for dirt, dust or any other foreign particle
  • Check for any type of dried liquid or chemically stuck to the button(s)

If everything seems to be working properly superficially, the problem might lay internally.

3. Check the Lens Focus Dials or Knobs

Now check the lens assembly and lens focus dials and knobs. The follong are some simple guidelines to aid you:

  • Have the projector powered on
  • Project any type of image or video towards your preferred surface
  • Turn the dials
  • Turn the knobs
  • Turn the lens
  • Look out for any resistance from the physical dials or knobs
  • Check if the lens is moving or not when you move these buttons
  • Evaluate the projected image or video as you try to focus

If you can see and feel any resistance when trying to operate this feature, maybe it's time to disassemble the projector.

4. Disassemble the Projector

If the problem seems to be internal, it is time for you to get a few tools ready to disassemble your projector. It is very important that your projector is off and unplugged before attempting any type of disassembly. You can also lose your warranty if you open the projector, so we recommend you contact your manufacturer or seller first to see what are your options. To disassemble your projector you’ll need:

  • A screwdriver that matches the screws on your projector
  • Trays to label the removed components and screws
  • A stable work surface like a workbench or desk
  • A guide or manual on how to adequately disassemble your projector

5. Check the Lens Assembly and Keystone Button(s) From Inside

Now that you have opened your projector, it is time to take a look at the specific components that might affect your issue. Here is what you should be looking out for:

  • Dust or dirt stuck to the lens assembly
  • Dust or dirt stuck to the keystone button(s)
  • Foreign substances stuck to the components
  • Foreign debris inside the components
  • Out of place components or plastic

If you spot any of these issues, try to remove them by using a can of compressed air or a small vacuum cleaner. You can also remove any foreign debris by hand, but be careful not to touch the components too much. If any part of the lens assembly, keystone button(s) or component seems to be out of place, put it back into place carefully, an online guide or manual can really help you at this point.

6. Test Your Results

It is time to test the results of your work! After re-assembly, simply power on your projector and try focusing your desired image or video. Most of the time changing surfaces or the location of your projector will fix the issue. The cleaning and checking of the inner workings of the projector should have also fixed the issue. Make a detailed evaluation of the features, if they work or not, and test it in various ways (e.g. projecting different types of media, focusing the lens in a different position, using keystone correction on several surfaces)

Can You Replace The Projector Lens Or Correct the Keystone?

As far as the keystone correction is concerned, replacing the button(s) or the control unit yourself will be a task that requires profound technical knowledge. We highly advise you to contact the manufacturer to see if they can fix this issue, or at least send you a replacement projector.

Changing the lens in your projector is actually a much easier task. You can find replacement lenses online and guides on how to perform the replacement yourself, and best of all, you don’t need to have the specific technical knowledge to accomplish this. Just follow some simple steps as below:

  1. Check your projector model
  2. Look for replacement lenses that fit your model
  3. Have a screwdriver and some trays for labeling ready
  4. Look for a guide or manual on replacing the lens of your particular model
  5. Disassemble the projector
  6. Perform the replacement
  7. Assemble the projector
  8. Test your results

What if the focus or keystone still doesn’t work? Well, this can be very frustrating. If proper maintenance was never applied or the fixes didn’t seem to work, we recommend you contact the manufacturer or seller so you can send your projector for professional repair or replacement.


We hope this article will help you understand what might cause your focus and keystone issues. All it takes is a bit of knowledge, determination, and some common tools to be able to make a good analysis of what might be acting up with your projector. So, why the focus (or the keystone) doesn’t work (can’t move)? We have learned that assembly errors can cause certain components to fall out of place, we also learned that the position and angle in which you are using your projector is important.

One of the most common issues is the type of surface you try to project into, so changing that up might be a good idea as well. We also looked at a few easy repairs and some more complex ones. Always remember to contact your seller or manufacturer if fixing the projector by yourself seems too difficult. But if you have patience and some willingness to learn, the following guidelines can be a good approach for you to achieve more complex fixes. Good luck!

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