JVC 370 SC, 330, 340 SC service manual Service Adjustments

Chapter 3---Service Adjustments

4.When the hot spot is at the center of the screen, retighten the four (4) Arc Lamp holding screws.

X and Y
Adjustments
	Z axis set screw
3 of 4 Arc Lamp
Holding Screws
(bottom screw	Z-Axis Adjustment
not shown)

Figure 3-10Model 330 Arc Lamp Adjustments (the Heat Sink has been removed for photograph).

To refocus the Model 330 Arc Lamp:

1.Loosen the Set Screw on the Arc Lamp shaft.

2.Adjust the Z-axis hexhead screw so that the screen is fairly even in brightness from center to the corners with the center being the brightest.

3.Use a light meter and adjust the Z-axis adjustment screw for a roll-off (drop in brightness from center to corners) of a maximum of 4:1 (preferably closer to 2:1).

Example: If the center of the screen measures 20 foot-candles, the corners should measure 10 foot-candles ideally,

but no less than 5 foot-candles.

CAUTION! Do not leave the roll-off at a value higher than 4:1, or the center may be too bright and could result in damage to the cold mirror.

4. Retighten the set screw.

Model 330, 340SC, 370SC Service Manual 3-19