JVC 250 Service Manual page 111

Chapter 5---Electronics
CRT Electronic Focus
The Electronic Focus is factory-set and normally will not need to be adjusted
except after component replacement, maintenance, or if wide temperature
variations exist between the factory and the field location. View one color at a
time.
Tools Needed
Medium Phillips-head screwdriver
To perform the Electronic Focus adjustment:
Remove the front and rear cover.
1.
Power the projector ON and allow it to stabilize for at least 15 minutes.
2.
3. Select the Focus pattern (test pattern #6).
4. Zoom the Projection Lens to the widest angle and adjust the Projection
Lens focus for the sharpest image.
5. View Green. Hide Red and Blue.
6. Adjust the Green Electronic Focus located on the side of the High Voltage
Power Supply (see Figure 3-5 and 3-6) for a sharp focus of the Focus
pattern at the center of the screen.
7. Repeat the above steps for Red and Blue.
Figure 5-30 View of CRTs, Relay lenses and ILA
5-56
®
Assemblies.
Model 250 Service Manual