Thursday, April 28, 2016

Infocus IN72 – IN74 – IN76 – Infocus projector Led flashing – Power up the projector without case – Color wheel function – Choking main board voltages – How to check the thermal swatch – Projector repair and service

Category: Projector Repair and Service 

Contents of this article 

  • LED flashing and causes 
  • Color wheel description
  • Mother board Voltage test points 

Infocus IN72 – IN74 – IN76

Power Up with Top Case Removed
Remove the top case and power up the projector to check fan or thermal switch operation. You also do this to check internal voltages and signals, which may require additional projector disassembly. Here's how to prepare the projector for power up with the top case removed.
1. Remove the top case
2. Use vinyl electrical tape or other non-conductive means to hold the safety switch actuator in the depressed (closed) position
The projector can now be plugged into a power source and powered up.
The projector communicates its status via an LED located on the keypad. When this status LED is green, you know that the projector is working properly. When the status LED is solid red or flashing red, you know there are lamp, power or startup problems. The frequency with which the status indicator blinks red indicates one of several error codes. These error codes provide crucial information about projector malfunctions.

LED Status
LED flashes green
The projector is starting up after the Power button was pressed, or the projector is shutting down after the Power button was pressed.
LED is solid green
The projector is ready to light the lamp when the Power button is pressed. Or the lamp is lit and the projector is operating properly.
LED flashes red one (1) time
The lamp won't strike after five (5) attempts. Check the lamp and lamp door installations for loose connections.
LED flashes red two (2) times
The lamp counter hours have exceeded lamp life hours. Replace the lamp and reset the lamp hours counter.
LED flashes red three (3) times
Lamp failure. Projector shuts down.
LED flashes red four (4) times
The fan has failed.
LED flashes red five (5) times
The projector is overheating.
LED is solid red
Undiagnosed error. Projector shuts down.
 Check the Thermal Switch
The thermal switch is designed to open when the temperature inside the projector gets too high. When the switch opens, the power supply shuts down, turning the projector off.
When the projector shuts down after operating for a few minutes or when the lamp fails to strike after repeated attempts at startup, check the thermal switch. First, power up the projector with the top off .Let the projector run until it shuts down. Measure resistance across the terminals at the thermal switch. If the resistance is infinite (Ω), replace the lamp housing, which includes the thermal switch.
Check fan operation
You can visually check the operation of the fans to see if they both work properly. Check the fans if the projector exhibits symptoms of overheating or if the red status LED indicates that a thermal issue is present.
To check the fans, first prepare for projector power up with the top case removed .
1. Connect the projector to AC power.
2. Power up the projector.
When you start the projector, there is voltage present on the controller ECA and power supply. Be very careful where you probe and where you touch.
3. Follow the directions below to check the fans. The fans should both start up when you press the power button.
4. If a fan fails to operate, check the voltage at the connector on the controller to verify that the fan is receiving power. If a fan has failed, remove the fan and replace it .
AC Filter Board
The AC filter ECA fastens to a metal ground shield plate. The AC filter ECA includes the AC power connector and filtering components that ensure clean power reaches to the other projector components.
The AC filter ECA connects to the power supply ECA. A fuse on the AC filter ECA protects against internal shorts or supply surges. The fuses are not available as a replaceable part. Blown fuses typically indicate circuit damage and the need for ECA replacement
Color Wheel
The Color Wheel is to provide synchronized colored light to the optical engine. The Color Wheel connects to the ECA Controller via a ribbon cable. The Shroud is to provide a direct and uniformed light path from the lamp to the color wheel. The Shroud is fastened to the Lamp Cage. The Index Board reads color wheel rotation to maintain proper synchronization with the DMD and allow accurate image color reproduction
Check Controller ECA Voltages and Signals
1. Make sure the projector is unplugged.
2. Remove the power supply and AC filter ECA.
3. Remove the Shield Plate.
4. Position the power supply and AC filter ECA near enough to the projector to connect the controller/power supply cable from the controller ECA. You can do this if you turn the two ECAs over and connect it to the controller ECA in an upside-down position. This also leaves you room to access the controller ECA with measurement probes. Make sure to connect the AC filter ECA to the power supply.
5. Connect the lamp to the lamp cable connector at the side of the lamp housing. Make sure the connector fully engages the connector on the lamp module.
6. Position the top case right side up at the rear of the projector. Plug the keypad cable in.
7. Connect the projector to AC power.
8. Power up the projector, and check the voltages using the illustration below.