Connecting Laptops and Desktops to LCD Projectors and Scan Converters
Technology 4
Summer 2007
Nebo Elementary School
Instructor: Mr. Michaud

Key Concept: "Flow of Signal"

When connecting computers to video and sound devices, you will need to remember which direction the video or audio signal flows.  In video, the signal leaves the computer at the VGA/RGB port on the back of the computer.  This signal then then travels down the cable and into the LCD or Scan converter.  For desktop computers, you sometimes plug the monitor into the LCD or scan converter to see the picture on the computer screen.

Connecting an LCD Projecter:

A. Laptops:
Note: You will plug the VGA cable into the back or side of the laptop depending on model.

Computer Help: Display Modes

Most laptops have multiple display modes.  In Dell Laptops there are three display modes:  (Use Blue "Fn" -> F8 on Dell Laptops)
  1. Single Screen - Default when powered on without ac power.  You only see the screen on the laptop.
  2. Dual Screen - Use w/ LCD Projector
  3. External Mode - Used rarely only outside moniter.

Procedure: LCD and Laptop
  1. Plug all together.
  2. Power on projecter (This will help the computer detect the projecter on startup.)
  3. Power on laptop.
  4. Make confirm connection and signal between Laptop and LCD.
  5. Use "Blue Fn-F8" to switch monitor mode if needed.
  6. Power down: Use button to power down, do not unplug LCD until fan turns off.
B. Desktops
  1. Power on desktop.
  2. Unplug moniter from back of desktop
  3. Plug VGA cable to back of computer to connect LCD
  4. Connect Moniter to LCD
  5. ("Through" concept signal passes through device)
  6. Power on projector - adjust resolution as needed

Computer Help:  "My screen looks messed up, What do I do?"

If the projector does not properly render the screen (parts of it are missing), Do the following steps: 
  1. Right-click on desktop of the computer.
  2. Select display properties
  3. Change the resolution to 800x600
  4. Change the resolution back to 1024x800
  5. That should fix the projector.

Laptops and Desktops: Connect to Scan Converter and Television

Remember the key concept, "Flow of Signal?"  When you connect a computer to a Television Set you are directing the Video Signal from the computer to the scan converter.  The scan converter splits the signal into two streams.  One stream is an RCA type signal to the Television Set.  The second is a VGA signal to the Computer Moniter. 

Process for Scan Converter:
  1. Connect the Computer to the Scan Converter via the VGA cable.
  2. Connect the Computer Monitor to the Scan Converter VGA out.
  3. Run an RCA cable from the Scan Converter to the VCR "Video In"
  4. (Some newer television sets have a directo "Video In."  If so, connect the scan converter directly to the Television sets.)
  5. Connect the VCR to the Television set using a Coaxial cable.  (Looks like the cable you use for cable television)
  6. Turn on Computer, Scan Converter, Monitor, VCR, and Television.
  7. Confirm the signal and picture.

Computer Help: "Why can't I see the computer picture on the TV set?"

Do the following steps:
  • Put a VCR tape in the VCR to make sure the VCR is sending a good signal to the Television Set.
    • (If this does not work, make sure the TV is set to channel 3 or 4)
  • Make sure the RCA cable from the Scan Converter is plugged into "Video In" on the back of the VCR
  • Set the VCR Channel to "Line" or "Line 1, Line 2" or "Aux" (Remember, VCR's have a channel tuner just like a TV Set.)

Exercise: Using the Laptop, Desktop, LCD and Scan Converter, connect these together to show a PowerPoint on a screen.