JVC 250 service manual Air Filters, IR Detectors, EMI Filter

Chapter 6---Miscellaneous Items

6.4Air Filters

There are three polyurethane air filters in the Model 250. Air filters should be cleaned whenever necessary. In extremely dusty or dirty conditions, the filters should be cleaned more frequently. Remove the filters and vacuum them or blow them clean with compressed air.

The air filters just slide out. No tools are required to remove and reinstall any of the air filters. They are located as follows:

!1 metal-framed filter in the rear of the projector in the bottom cover- accessible when the rear cover is off.

!1 filter on the bottom of the projector-slides out from the middle-left side of the projector (grasp the hole in the filter frame). The filter can be peeled off the Velcro on the frame, if necessary.

!1 metal-framed filter in the front-left-bottom cover accessible with the front cover off.

6.5IR Detectors

The IR Detectors receive command signals from the IR Remote Control. The Model 250 projector has two IR Detectors, one on the front of the projector and one on the rear (mounted on the System Controller PCB). The command signals go to the System Controller PCB where they are distributed to the various PCBs, typically by way of the IIC data bus. The IR Detectors can receive commands from an IR Remote Control from a range of about 45-ft. line of sight.

6.6EMI Filter

Figure 6-2EMI Shield with Low Voltage Power Supply and Arc Lamp Power Supply behind it

The purpose of the Electro-Magnetic Interference (EMI) Shield is to trap and collect electromagnetic radiated fields generated by switching power supplies. Switching power supplies radiate high frequency noise that may interfere with radios, televisions, and other electronic appliances. The EMI Shield is constructed of a special Mu metal that acts as an antenna to collect and ground the high frequency noise as required by the Federal Communications Commission and various other regulatory agencies.

6-4 Model 250 Service Manual