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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.