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ADJUSTMENTS
READ PULSE WIDTH AND WRITE PULSE WIDTH ADJUSTMENTS
Use Figure 7-1 for locating test points.
1. Do the preceding power-on, and warm up steps (PLL ADJUSTMENT
Steps 1 through 3).
2. Attach the oscilloscope test lead to the RPW test point.
3. Observe the waveform
pulse width (see Figure 7-2). The pulse width should be 250 ns £10%. If
out of tolerance, adjust R31.
4. Attach the test lead to the WPW
test point and observe the pulse width. The width should be
125 ns 10%. If out of tolerance, adjust R22.
5. Remove the jumper from the TEST VCO test point.
6. Verify disc operation as in step 5 of the PLL Adjustment.
TEST POINTS:RPW=
250ns.
SCOPE
SETTINGS:
1V/div., 0.5us/div.
Figure 7-2. Read/Write Pulse Width.
7-3
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