Adjusting The Edge Aberrations For Board 5500A-4004-1 - Fluke 5500A Service Manual

5500A
Service Manual
11801B Setup
Voltage/division
dc offset
Dot Response
Smooth
Time Base Position
Time/division
Trigger Level
Trigger Input
External Trigger
Sequential
Scan Repetitive

6-152. Adjusting the Edge Aberrations for Board 5500A-4004-1

Follow this procedure only if you have Board 5500A-4004-1 (Fluke PN 600749).
1. Adjust the dc offset on the 11801B so the last 500 ns of the peak of the square wave
2. Change the time/div on the 11801B to 20 ns/div.
3. Slowly adjust pot R168 and observe its effect on the waveform. the left half of the
4. Change the time/div on the 11801B to 5 ns/div.
5. Slowly adjust R57. It will affect the first 50 ns of the wave form. Adjust R57 so the
6. Change the time/div on the 11801B to 2 ns/div.
7. Adjust R16 until the rising edge ledge reaches the center line. Refer to Figure 6-35.
8. Return to 5 ns/div and verify that the pattern shown in Figure 6-34 still exists.
9. At this point in the adjustment, each graticule line on the oscilloscope represents a
6-118
10 mV/div
Centered
Centered
On
5 µs
0.5 µs
Center, negative slope
x10
1 MΩ
On
On
is on the center line.
wave peak will move up and down as you turn R168. Adjust R168 until the center of
the wave peak is half of a division above the center line, as shown in Figure 6-33.
rising edge falls back and crosses the horizontal center line one division before the
vertical center. Refer to Figure 6-34. The base of the aberration should be 10 ns
apart.
Repeat the adjustment in step 5 if necessary.
1% aberration. Typically this board shows aberrations of 0.5% within the first 10 ns,
and aberrations of 0.25% during the following 10-30 ns.