An
incorrect setup can cause Smart Interactive Whiteboard projector display
problems. Although the first impulse is to blame the projector or computer, the
problem is almost always caused by the connection between them. A bad setup can
result in one or more of these issues:
1 . A blurry or fuzzy image.
2. No image.
3. An image that is displaced or distorted.
4. Incorrect scaling.
5. Weak colors, or no color (black and white).
6. A wavy image.
7. Ghosting
8. A vibrating image, or cyclic distortions.
The correct signal is not getting through. The smart interactive whiteboard
projector is doing its best job to make sense out of a distorted signal, but
the result is less than satisfactory.
To fix the issue, you must understand how the computer and projector should be
connected, and what can interfere with the signal. You can then inspect your
setup and fix it.
You will need to understand which equipment you should use, and how to
configure the computer. Armed with this knowledge, it becomes easy to fix and
prevent the majority of display problems.
Avoiding Interference and Signal Degradation
If your projector is very close to the computer, it should be connected
with a short cable. It's the same type of cable which is used to connect your
computer to a monitor - it's usually only a few feet away. The signal does not
require boosting to travel such a short distance.
When the distance between the computer and the projector grows, it becomes
necessary to use a longer cable. Longer cables introduce two problems to a
signal. First, it takes more power to push the signal through the longer cable.
Unless the signal is amplified, it will be too weak at the other end, which
will cause degradation and a poor display.
The way to handle this issue is to boost the signal, with an active VGA
splitter. The VGA splitter contains an amplifier, which is a circuit that
boosts the signal strength to push it through a longer cable.
Another issue with a long cable is interference. Interference can cause
ghosting, wavy lines, and rhythmic distortions on the display. Sometimes it can
completely obliterate the original signal.
A long cable is like a radio antenna, and strong electromagnetic fields can
cause signal distortion. Cables are shielded to prevent this from happening,
but if the cable is very close to a power line or a transformer, it can pick up
a lot of interference.
Often, cables are routed together to keep them out of the way. They are often
routed through the ceiling "crawl space", or in the walls.
The best way to avoid interference is to re-route the cable. If that's not
possible, then a temporary solution is to use another cable, and ensure it is
not placed near a source of interference.
Y-Splitters
Projectors
usually come with a Y-splitter, which is used to connect your computer to 2
devices at the same time. Some people mistakenly think that the Y-splitter is
an essential part of the setup for your projector - it's just for special use
cases.
Y-splitters exist so you can use a smaller monitor to control your presentation
while your audience watches the Smart Interactive Whiteboard. It's a practical
consideration that has a lot to do with stagecraft. It's acceptable for a
presenter to look down at a screen, but it's offensive to turn your back on an
audience to look at the whiteboard.
The problem with a Y-splitter is that it halves the signal strength, so you
must use it with an active splitter or signal booster.
You should not be using a Y-splitter unless you need to connect a second
monitor to the same output signal. Often, this is not the case. For instance,
if you have a notebook, you can use its screen as a monitor for your
presentation. If you do use a Y-splitter, you must also boost the signal with
an amplifier.
An alternative is an active VGA splitter. This is a device that boosts the
signal and splits it into several outputs. The signal will be strong enough to
travel over a longer cable - or several cables.
Y-splitters can cause problems on your computer, too. Your operating system has
a video driver that sends the video signal to the projector. To make the right
signal, it needs to discover which resolutions and frequencies the monitor can
accept. So it communicates with the monitor (or projector) when the computer
boots. But if there is a projector and a monitor connected through a
Y-splitter, the driver will get confusing replies to its queries. The result is
that it won't be able to format the signal correctly.
Power Supply
One of the most frequent causes of problems for powered equipment is when the
power supply has been disconnected or switched off. An active VGA splitter or a
VGA booster require power, and if the power is disconnected or switched off,
the signal will become weaker (or maybe cut off completely).
Cable Damage
Cables can be damaged by stress and tension. This damage will break or degrade
the signal. It can cause interference, intermittent white noise, or any of the
other problems mentioned above. There is a procedure to check cables for
faults, which I will cover in the troubleshooting section.
Connection Errors
The active VGA splitter has a number of outputs. If you connect your cable to
the wrong one, your Smart Interactive Whiteboard projector will not get the
right signal. The computer will not be able to communicate to the projector to
get the right configuration, which will cause it to send the wrong output.
Configuration Errors
Your computer is designed to be able to connect to a wide range of display
devices. When you connect it to a specific device, it has to send the right
type of signal. The important variables are resolution and frequency.
Modern computers, monitors and projectors are programmed to work these settings
out automatically between themselves. They communicate and work out the best
settings. Connecting the devices incorrectly can prevent this conversation from
taking place.
Another problem that can prevent them from communicating is if you turn your
computer on before the projector. The computer will get no reply from its
queries.
A user can manually override the frequency and resolution settings in the
"preferences" dialog. So it's possible that your settings are
preventing the projector from displaying properly.
Troubleshooting
The above sections have been a quick orientation to the major components and
how to connect them together. It's important to understand the ideal configuration
to discover what is wrong with your current setup.
Troubleshooting is actually very simple when you know how things should be
connected and configured because the cause of the problem will stick out like a
sore thumb. That's why experienced engineers can tell what is wrong with a
system with a single glance.
It's a good idea to sketch out the ideal configuration of your equipment on a
piece of paper so that you understand how it should be set up.
The next step is to take a look at how it is actually setup. Here is a
checklist to help you systematically inspect your Smart Interactive Whiteboard
projector setup:
1. Switch everything off.
Switch off the computer, the projector, and any active splitters.
2. Is the projector
close to the computer?
If
it is, then you should connect the computer directly to the projector with a
short cable. The signal does not need to be boosted through an active splitter,
as it only has to travel a short distance. The only exception would be where
the short cable poses a serious tripping hazard, or would be under tension,
causing damage.
Always favor a simpler setup, there is less that can go wrong.
Now you will need to test if the problem is resolved. Continue with step 10
below.
If the projector is some distance from the computer, check the following
points:
3 . Is there a Y-splitter?
You should use an active VGA splitter instead. It will boost the signal,
and it can split it for multiple displays.
4. Is there an active VGA splitter, or a
signal booster?
If not, you will need to remedy this. The signal must be boosted to ensure
it doesn't degrade as it passes through the extension cable. Get one, and
connect it to the VGA output of the computer. The VGA extension lead will be
connected to the active splitter or VGA booster.
5. Is the power cable connected to the
active VGA splitter/booster?
The active splitter/booster is a powered device, and will not work without
electricity.
6. Does the VGA splitter power supply
work?
There should be an LED indicator on either the power supply, or the active
splitter, or both. Test it by switching the power on and off. If it does not
work, replace it. Do not open the power supply unit! There are very high
voltages inside, and even experienced electrical engineers simply replace them
when they stop working.
7. Is the VGA extension cable plugged
into the correct output port of the active splitter?
The active splitter has several output ports. In order for the computer to
communicate correctly, your extension cable must be connected to the DDC port.
8. Is the extension cable close to any
obvious sources of interference?
Power cables and transformers in power supplies are the main cause of
interference. If you can re-route the cable away from the source of interference,
this could fix the entire problem.
If the extension cable is out of sight, you might not be able to check for
sources of interference. If you confirm that the error is due to the extension
cable, you can get an electrician to check its routing at a later point. If
there is interference, they can re-route it to eliminate the problem.
9. Is the Smart Interactive Whiteboard
projector connected?
The VGA extension cable should be connected to a short cable, which
connects directly to the projector.
10. Switch everything back on in the
following sequence.
(1). Switch the projector on first.
(2). Switch on the VGA booster or active splitter
(3). Switch on your computer.
Let the computer and projector power up and communicate with each other.
11. Check the display driver
configuration
If there is still a problem with the display, check your display driver
settings. Try different resolutions and refresh rates to see if that remedies
the problem:
12. Test the active VGA splitter/booster
and VGA extension cable
(1) . Measure the length of the cable from the active VGA splitter (or
booster) to the monitor. Check the splitter/booster manual to see if it is
capable of supporting that distance.
(2). Test connecting the computer directly to the projector with a short cable
(move it first). Switch everything off. Then turn on the projector followed by
the computer. If the display does not work, try different resolution and
refresh rate settings, as in step 11.
If you cannot get it to work, try another short cable.
If it still does not work, try connecting the computer to another monitor. Does
that work? If so, the fault is in the projector. Otherwise, it is the computer
that is faulty.
Either way, you will need to get the defective equipment serviced by an
engineer or by the manufacturer.
(3). If the computer worked with the short cable, test the booster or active
splitter by connecting it to the computer, and use the short cable to connect
it to the projector. Does it work now? If so, the booster or active splitter
are not faulty.
(4). Now use the extension lead. The connection should now go like this:
computer -> signal booster/active splitter->VGA extension cable ->
short cable -> projector.
Test this setup as before.
If the display is poor, then you have isolated the fault to the extension lead.
Replace it and the display should be optimum.
It is possible that there is more than one fault, so it's worth checking every
point on the troubleshooting checklist. By being thorough, you can also catch
degradations before they become full-blown faults.
Once you have a working Smart Interactive Whiteboard projector setup, look
after the equipment to keep it in good working order. Do not put the cables under
stress, or leave them where they people can accidentally tread on them or yank
them.
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