Extron electronic PA 300 - Manual (Page 11)

PA 300 Peaking Amplifi er • Adjusting the Display
Adjusting the Display
PA 300 Peaking Amplifi er • Adjusting the Display 3-2 3-3
Signal Compatibility
The PA 300 processes VGA-UXGA, RGBHV, RGBS, RGBsB,
RsGsBs, HDTV, and component video signals.
Potentiometer Adjustments
The PA 300 achieves its superior amplifi cation by using
two independent peaking potentiometers: LF for streaking
adjustment and HF for detail adjustment.
The goal in adjusting the PA 300’s Gain and Peaking
potentiometers is to produce a sharp image (i.e., an image free
of streaking or smearing) on the attached display.
The most accurate adjustment method for the gain uses an
oscilloscope, but you can also adjust by observation. The
following instructions explain how to adjust the gain with
and without the use of an oscilloscope. An oscilloscope is not
necessary for the peaking adjustment.
Adjusting the gain with an oscilloscope
To adjust the Gain potentiometer, do the following:
1. Remove the cable from your source and attach a VTG 300
to this cable.
2. Use the White Field test pattern for the VTG 300 setting.
3. Remove the far end of the cable from your projector and
attach the oscilloscope using 75 ohm termination.
4. Use an Extron Tweeker to adjust the Gain potentiometer
until you have a 0.7 Vp-p reading from the white top to the
black bottom of the scope.
5. Once the gain is successfully adjusted, replace the source
and display cables.
6. See Adjusting the peaking on the following page.
Adjusting the gain without an oscilloscope
Use an Extron Tweeker to turn the Gain potentiometer until the
image reaches the desired level of brightness.
Adjusting the peaking
To adjust the Peaking potentiometers, do the following:
1. Using MS Paint and a spreadsheet, create a testing image
on your PC desktop that includes squares, lines, text, and
gradations of color. Use the illustration below as a guide.
2. Adjust the LF (low frequency) potentiometer until the
image is free of streaking. When the LF is over adjusted,
the streaking is the same color as the image, as shown
below.