Fig. 6 Adjusting IR Calibration Wedge

a. Remove the Front Plate/Lens Panel (see Fig. 3) and replace it with the modified Front Plate shown in Fig. 5 (NPI 600AM #92-30 has more information).

b. Using a dental pick, narrow-bladed screwdriver or other suitable tool, adjust the IR calibration wedge (see Fig. 6). Move the IR calibration wedge counterclockwise (CCW) to decrease the reading or clockwise (CW) to increase the reading (see Fig. 6).

c. Replace the original Front Plate and retest the camera. Readjust the IR calibration wedge if necessary.

d. If the IR calibration wedge adjustment cannot bring the reading into specification, disassemble the camera down to the shutter level and examine the photocell area. Be certain the photocell is properly seated. Reassemble the camera and retest. Readjust the IR calibration wedge if necessary.

Fig. 7 Adjusting the Ambient Calibration Disc

a. Remove the Front Plate/Lens Panel (see Fig. 3) and replace it with the modified Front Plate shown in Fig. 5 (NPI 600AM #92-30 has more information).

b. Using a dental pick, narrow-bladed screwdriver or other suitable tool, adjust the ambient calibration disc (see Fig. 7). Move the ambient calibration disc clockwise (CW) to decrease the reading or counterclockwise (CCW) to increase the reading (see Fig. 7).

c. Replace the original Front Plate and retest the camera. Readjust the ambient calibration disc if necessary.

d. If the ambient calibration disc adjustment cannot bring the reading into specification, disassemble the camera down to the shutter level and examine the photocell area. Be certain the photocell is properly seated. Reassemble the camera and retest. Readjust the ambient calibration disc if necessary.

Calibration of the B-600 Tester is done in three steps:

(1) calibrating the Light Source,

(2) the Horn and

(3) the Electronics Unit.

While the probability of the B-600 going out of calibration is unlikely, the B-600 should be checked daily.

Calibrating the B-600 Light Source

Light Source calibration is done using a 640 Master Camera, which measures light levels in both the visible and infrared regions.

Two switches are located on the top of the Camera: Motor ON/OFF prevents the Camera from cycling while it is used as a light level standard, and Meter ON/OFF controls the meter on the back of the Camera. A slide on the front of the Camera, next to the lens, controls the blade opening.

Calibration procedure:

1. Turn ON the light source and let it warm up for 30 minutes.

2. Slide the Master Camera on the horn with the motor switch OFF and the meter switch ON.

3. Place the Master Camera in front of the Light Source window. Set the light level for 100 cd/sq. ft.

4. Slide the blade control all the way to the left (as viewed from the back of the Camera) until you hear a click. This signals the blades have unlatched.

5. Slide the blade control all the way to the right: this is the blade position at which the standard camera is indicating the visible light level. Since the standard camera is a direct reading device, the meter reading is the actual light level.

6. Tilt the camera and the horn back so that the shutter blades can be seen through the taking lens.

7. Slide the blade control to the left until the shutter is at full aperture: this is the point at which the camera will indicate the IR light level.

8. Place the camera back in front of the Light Source: the meter reading should be 3.5 to 4 times the visible mode reading. (Ideally, the visible reading should be 100 and the IR

reading 350 to 400.)