2. Service
Assembly/Module Diagnostic Trees (Diagnostic Section 3)
122
3.9.1.3 A6J4.1 and A6J4.9. Reference Voltage Test
1
Verify reference voltages on A6J4.1/A6J4.9. with a DMM:
A6J4.1 (nominal 5.000)
>
4.995 and
<
5.005 volts
A6J4.9 (nominal -5.000)
>
-5.005 and
<
-4.995 volts
QUESTION:
Are the voltages correct?
If Yes:
Go to, 3.9.1.4.
If No:
Remove power. Check fuses A6F1 and A6F2. If blown, replace
and repeat this step. If not blown, replace A6, and retest.
Top of A6 Board
⇑
z
z
Pin 9
z
z
z
z
z
z
z
z
⇐
J4 Jumper Layout
z
z
z
z
z
z
z
z
Pin 1
3.9.1.4 EFC Voltage Test (1)
1
Record the position of the jumper connecting the left-hand row of
pins of A6-J4 with the right-hand. (The jumper positions number
1 through 9, beginning at the bottom.)
2 Use
the
INFO/Ctrl
menu to determine the EFC control voltage as
a percentage between -100% and +100%.
3
Calculate the expected EFC control voltage using the formula:
Control voltage=1.25*(5-Pos.Jmpr)-0.03308*(%Ctrl). For example, if the
jumper is in the 6 position and the control is +8%,
control voltage = 1.25 * (6) -0.03308 * (8) = 7.24.
4
Measure the EFC control voltage applied to the oscillator at A6J6.
5
Verify that the measured and calculated voltages agree to within
0.03 volts.
QUESTION:
Do the measured and calculated EFC voltages agree to
within 0.03 volts?
If Yes:
Go to, 3.9.1.5.
If No:
Go to, 3.9.1.4.1.
Summary of Contents for 5071A
Page 2: ......
Page 40: ...1 Performance Tests Verifying Specifications 5071A Complete Performance Tests 24 ...
Page 48: ...2 Service Pre Troubleshooting Information 32 Figure 2 1 Instrument Top View ...
Page 168: ...3 Theory of Operation Functional Block Descriptions 152 Figure 3 5 Power Supply Block Diagram ...
Page 173: ......
Page 194: ...5 Replaceable Parts How To Order A Part 178 ...
Page 197: ......
