Quad Standard Decoder/Line Doubler Vic - JVC 250 Service Manual

Chapter 5---Electronics
when the S-image input is selected. Only one LED will be illuminated at one
time. Neither LEDs will be illuminated when the Quad Standard Decoder VIC is
not selected as the input to projector.
Quad Standard Decoder VIC - Service Adjustments
There are no physical service adjustments to the Quad Standard Decoder VIC.
Quad Standard Decoder VIC - Remove and Replace
Tools Needed
#0 Pozi-drive Phillips-head screwdriver
Parts Needed
Quad Standard Decoder VIC p/n 103545
To remove the Quad Standard Decoder VIC:
1. Power off the projector by IR Remote or PC, and allow the cooling fans to
run until they shut off automatically.
2. Turn the AC Circuit Breaker to the OFF position and unplug the AC
Power Cord.
3. It is not necessary to remove the rear cover.
4. Disconnect the input BNC cables from the VIC.
5. Remove the two retaining screws from the faceplate of the VIC.
6. Pull the VIC out of the Electronics Module.
7. Reverse the process to install the VIC.

Quad Standard Decoder/Line Doubler VIC

The Quad Standard Decoder/Line Doubler VIC is very similar in function to the
Quad Standard Decoder VIC. It accepts the same two source input formats,
Composite and S-image and processes them exactly the same. It has two LEDs
that function exactly as the Quad Standard Decoder VIC. The inputs, outputs and
signal processing are also the same. Selecting the VIC is done in the Channels
Menu, the same as the other VICs. There are two distinguishing differences. The
Quad Standard Decoder/Line Doubler VIC doubles the horizontal scan frequency
of the input source. The other difference is that the Quad Standard Decoder/Line
Doubler VIC takes up two VIC slots.
The Line Doubler section doubles the horizontal scan frequency of the input
source. As an example, if the input source is a Composite signal in NTSC, which
has a line rate of about 15 .75 kHz, the Quad Standard Decoder/Line Doubler VIC
doubles the line rate to 31.5 kHz. This provides a much cleaner display on the
screen.
The Quad Standard Decoder/Line Doubler VIC takes two VIC slots, even though
the faceplate only covers on space. Some of the components prevent it from
fitting into one VIC slot. When the Quad Standard Decoder/Line Doubler VIC is
5-72 Model 250 Service Manual