Monitor Audio Vector Service Manual download pdf (Page 91)

Adjustment Procedures: Analog Section

WFM90D and WFM91D Service Manual

5-7

Vertical Gain and X5 Gain Registration

Perform these steps to adjust the vertical gain and X5 gain registration:

1. Replace the signal on the VIDEO IN connector with the output from the

VAC. Do not terminate the input.

2. Set the VAC for a 999.9 mV output with all of the buttons out except +LUM

and NTSC (PAL button for the WFM91D).

3. Select X1 GAIN from the Calibration menu, and then select CAL.

4. Adjust the arrow buttons for a display amplitude of exactly 140 IRE

(1000 mV PAL).

5. Select CAL MENU, and then select SAVE.

6. Set the VAC for a 199.9 mV output.

7. Select X5 GAIN from the Operating menu.

8. Select X5 GAIN from the Calibration menu, and then select CAL.

9. Adjust the arrow buttons for a display amplitude of exactly 140 IRE

(1000 mV PAL).

10. Select CAL MENU, and then select SAVE.

11. Replace the signal on the VIDEO IN connector with a 75% color bar signal

from the television signal generator, using a 75 Ω in-line termination.

12. Select X5 POS from the Calibration menu, and then select CAL.

13. Select X1 GAIN, and then position the signal baseline to the graticule

baseline.

14. Select X5 GAIN from the Calibration menu, and then select X5 POS.

15. Use the arrow buttons to return the signal baseline to the graticule baseline.

16. Select X1 GAIN from the Calibration menu.

17. Select CAL MENU, and then select SAVE.

18. Remove the signal and termination from the VIDEO IN connector.

Frequency Response

Perform these steps to adjust the frequency response:

1. Connect a 50 Ω precision cable from the leveled sine wave generator output

to the dual-input coupler using a 50 Ω-to-75 Ω minimum loss attenuator.

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Monitor Audio Vector Service Manual Page 91