Question 1

the fan on my cinebeam is crazy loud all of a sudden, like it's running at full speed even when the picture is dark.

Accepted Answer

DIAGNOSIS The projector's internal temperature sensor thinks it's overheating, so it's commanding the cooling fan to run at maximum RPM to try to save the laser and electronics. This is a protective mode. FIX The first thing to check is airflow. 1) Power the projector down completely and let it cool for an hour. 2) Unplug it. 3) Carefully inspect all the vents—intake on the side/front and exhaust at the back. Use a vacuum with a soft brush attachment to thoroughly clean every vent you can see. Make sure nothing is blocking the vents (books, curtains, walls). The projector needs several inches of clear space on all sides, especially the exhaust. 4) Check the room temperature. Is it unusually hot in the room? The projector works harder to cool itself in a warm environment. IF THAT DIDN'T WORK If cleaning the vents doesn't solve it, the internal temperature sensor might be faulty, or the thermal paste on the laser diode heatsink might have degraded. This isn't something you can fix. You'll need to note if the loud fan happens immediately on a cold start, or only after 30 minutes of use. That detail is important for the repair tech. HEADS UP Never ignore this symptom or try to use the projector for long periods with the fan screaming. It's a warning. Continuing to use it could lead to permanent damage from overheating, like a dimmer laser or a complete shutdown. If a thorough cleaning of the environment and vents doesn't return the fan noise to its normal, variable level, it's time to call LG support.

Question 2

i see a weird dark shadow or blurry spot in the corner of the image from my lg projector. it doesn't go away.

Accepted Answer

DIAGNOSIS That's likely a piece of dust or debris that has settled on the internal lens or, more seriously, on the surface of the DLP chip inside the sealed optical engine. It gets projected as a fixed shadow. FIX First, rule out an external problem. 1) Turn off the projector. 2) Gently wipe the external projection lens with a clean, dry microfiber cloth (like for glasses). Use a lens blower brush first to remove any loose grit. See if the spot moves or changes. If it's on the outside lens, this will fix it. If the spot is still there, try this: gently tap the side of the projector near the lens while it's on and displaying a bright, solid color (like a white screen). Sometimes, very fine dust can be dislodged by vibration and fall away from the critical optical path. IF THAT DIDN'T WORK If the spot is small, sharp, and black, it's almost certainly dust on the DLP chip. If it's larger and blurry, it could be on another internal lens. Unfortunately, there is no safe user fix for this. The optical engine is sealed to protect the laser and precision optics. Trying to open it yourself is dangerous (due to the laser) and will instantly void your warranty. HEADS UP This is a risk with any DLP projector. To minimize it, avoid moving the projector while it's on or still hot, as that can stir up internal dust. If the spot is very distracting, you need to contact LG support for a professional cleaning or repair under warranty. Don't let anyone tell you to use "projector cleaning mode"—this model doesn't have one.

Question 3

the built-in smart apps (like netflix) are super slow and keep freezing on my pu700r. my wifi is fine.

Accepted Answer

DIAGNOSIS This is a common gripe with built-in projector smart platforms. They often have underpowered processors and not much memory compared to a dedicated streaming stick, so they can bog down, especially after updates. FIX First, try a simple reset of the smart system. 1) Press the 'Home' button on your remote. 2) Navigate to 'Settings' (the gear icon). 3) Go to 'General' > 'Reset to Initial Settings'. Important: This will only reset the smart TV settings and logged-in apps. It will NOT reset your picture settings or input configurations. You'll have to log back into Netflix, etc. This clears out the cache and often speeds things up significantly. After the reset, only install the apps you actually use. IF THAT DIDN'T WORK The hardware might just be struggling. The best long-term solution is to bypass the smart system entirely. Get a modern streaming device like a Roku, Apple TV, or Fire Stick 4K and plug it into the projector's HDMI port. Use the projector as a simple display. Those devices are updated more frequently, are much faster, and will give you a better experience. Just set the projector to boot directly to that HDMI source in the settings. HEADS UP Avoid leaving the smart home screen running for hours. When you're done watching, actually turn the projector off with the power button. Letting it go into standby keeps some apps running in the background, which can slow it down over time.

Question 4

the auto keystone on my lg cinebeam keeps making the picture a trapezoid instead of fixing it. it's driving me nuts.

Accepted Answer

DIAGNOSIS The auto keystone correction is getting confused, usually because it's trying to correct for a surface that isn't a flat, white screen, or because the projector isn't close to level. FIX The best fix is often to turn auto keystone off and do it manually. Here's how: 1) Press the 'Menu' button on the remote. 2) Go to 'Picture' > 'Aspect Ratio & Keystone'. 3) Find 'Auto Keystone' and set it to OFF. Now you're in control. Go to 'Manual Keystone'. Use the arrow buttons on the remote to adjust the vertical and horizontal sliders until the sides of the image look perfectly straight and rectangular. It helps to pull up a test pattern (like the grid from the projector's built-in screen adjustment menu) to see the lines clearly. IF THAT DIDN'T WORK If adjustments seem extreme or can't get the picture square, the physical placement is too far off. The projector should be as level as possible (use a small bubble level on top) and positioned so the lens is roughly perpendicular to the center of your screen or wall. Adjust the projector's position or use the adjustable feet before you use digital keystone. Digital keystone degrades picture quality the more you use it. HEADS UP For the best picture quality, avoid keystone correction altogether. Take the time to physically mount or place the projector so the lens is square to the screen. Use the lens shift dials (the little wheels near the lens) for fine-tuning instead—that's an optical adjustment that doesn't hurt the image.

Question 5

my projector says 'no signal' but everything is plugged in. using hdmi from my fire tv stick.

Accepted Answer

DIAGNOSIS This is almost always a handshake issue between the projector and your source device. They're not agreeing on a video signal format when they first connect. FIX Let's reset the conversation. 1) Turn the projector OFF with the power button. 2) Unplug the HDMI cable from both the Fire Stick and the projector. 3) Unplug the Fire Stick from its power source. 4) Wait 30 seconds. Now, plug everything back in, in this order: First, plug the HDMI cable firmly into the projector's port. Then plug it into the Fire Stick. Next, power the Fire Stick. Finally, turn the projector ON. It should go through its search cycle and find the signal. If it doesn't, press the 'Source' button on the remote until you select the correct HDMI port you're using (HDMI 1 or 2). IF THAT DIDN'T WORK The issue could be the HDMI cable itself or a setting on the projector. Try a different, known-good HDMI cable—preferably a 'High Speed' one. If you have another device, like a game console, test that to rule out the Fire Stick. If another device works, the problem is with the Fire Stick. Go into the projector's menu: Settings > General > HDMI Ultra HD Deep Color. Try turning this setting OFF for the port you're using. Sometimes turning this advanced feature off fixes handshake problems with older streaming devices. HEADS UP If you're using a very long HDMI cable (over 15 feet), it might not support the 4K signal reliably. For long runs, you might need an active or fiber optic HDMI cable.

Question 6

how do you clean the filter on the lg cinebeam? i can't find it and the manual is useless.

Accepted Answer

DIAGNOSIS You're right to look for it—keeping the filter clean is crucial for cooling. On the PU700R, the air filter isn't a user-serviceable part you can pull out and rinse like on some older projectors. It's a fine, permanent mesh built into the air intake system. FIX Your maintenance is all about keeping that built-in filter and the vents clear. Here's what you do: 1) Make sure the projector is off, unplugged, and completely cool. 2) Locate the main air intake vent, which is usually on the side or front of the unit. 3) Use a vacuum cleaner with a soft brush attachment. Gently run the brush over the vent to pull dust out of the mesh. Don't press hard. 4) For the exhaust vent (where the hot air comes out), use a can of compressed air. Hold the can upright and give a few short bursts from the outside to blow dust out. Always blow from the inside out, or use the vacuum brush again. IF THAT DIDN'T WORK If you suspect the internal filter is heavily clogged (the projector is overheating and shutting down early), you've done all you can safely. The next step is to contact LG support. They can advise if it needs a professional internal cleaning, which involves opening the case—something you shouldn't attempt. HEADS UP Never use liquids, household cleaners, or a rough cloth on the vents. And avoid running the projector in a very dusty room or on thick carpet, as that will make it suck in more debris. A clean environment is your best filter.

Question 7

lg pu700r making a high-pitched whining or buzzing noise, seems to be coming from the lens area. is this normal?

Accepted Answer

DIAGNOSIS You're likely hearing the laser diode driver or the color wheel spinning at high speed. A faint, steady whir is normal, but a pronounced, high-pitched buzz or whine that changes with picture brightness is not. FIX First, identify when the noise happens. Turn off all audio and listen. 1) If the noise is constant once powered on, regardless of the image, it's likely a fan bearing or the color wheel assembly. 2) If the noise gets louder or higher-pitched when a bright white or colorful scene is on screen, that's the laser driver working harder. For the second case, go into the projector's menu: Settings > Picture > Advanced Settings. Look for a setting called "Dynamic Contrast," "Laser Output," or "ECO Mode." Turn Dynamic Contrast OFF and set the Laser Output or Picture Mode to "ECO" or "Cinema." This reduces the peak laser power and can often eliminate that specific electronic whine. IF THAT DIDN'T WORK If the noise is a grinding or rattling buzz, it could be a foreign object like a tiny piece of foam from the packaging stuck in a fan. You'll need to carefully inspect the intake and exhaust vents (with the unit off and unplugged) and use a can of compressed air to blow out any debris. Don't shake or tilt the projector aggressively. HEADS UP Never try to open the sealed optical engine yourself to get at the color wheel. That's a laser safety hazard and will void your warranty. If the noise is mechanical and the compressed air trick didn't help, it's a job for LG service.

Question 8

my new lg cinebeam pu700r won't turn on at all, the power button light just blinks red a few times and then nothing.

Accepted Answer

DIAGNOSIS The projector is failing its internal power-on self-test. A blinking red light is its way of telling you something's not right before it even tries to fire up the laser. FIX First, unplug the power cord from the wall and from the back of the projector. Leave it completely disconnected for a full two minutes. This gives all the internal capacitors time to drain. While you're waiting, check the power cord for any kinks or damage. After two minutes, plug the cord firmly back into the projector first, then into the wall outlet. Make sure you're using the original power cord that came in the box. Now, press the power button on the projector itself, not the remote. Listen closely; you should hear the cooling fan start to spin up. IF THAT DIDN'T WORK If it still blinks red, the issue might be with the power supply sensing a problem. Try a different wall outlet on a different circuit in your house, like one in the kitchen or bathroom. Don't use a power strip or surge protector for this test—plug directly into the wall. If it works on another circuit, the original outlet might be faulty or underpowered. HEADS UP If it only works on the remote and not the physical button, that's a different problem—likely a stuck or faulty power button on the unit itself, which would need service.

LG CineBeam PU700R 4K Laser Projector

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