Trigger Circuit Troubleshooting (Figure 3-8) - Agilent Technologies 6060B Service Manual

During the pauses, use a logic probe to make the following checks:
Toggle Mode
U313-3 = LO
U312-3 = LO
U316-9, 11, 14 = LO
U316-12 = HI
After the pause, press "Continue" to generate the next trigger.
FRONT
PANEL TRANS_EN
ACTION signal
Turn on TTL Lo
unit
TTL Hi
Press
Press TTL Hi
Press TTL Lo

Trigger Circuit Troubleshooting (Figure 3-8)

The Electronic Load can receive an internal trigger (command via the GP-IB) or an external trigger signal (TRIG_IN via
connector TB201). Either trigger can be used in triggering a preset level (current, voltage or resistance value) or in
triggering a pulsed or toggles transient operation. Troubleshooting the trigger circuit consists of running programs that
generate trigger pulses and then making sure that the signal lines shown in Figure 3-8 toggle in the direction indicated. If a
signal line does not toggle where indicated, the gate or IC that generates that signal is probably defective.
The arrows on Figure 3-8 indicate the signal line activity when using a logic probe and running the programs. Connect
TP201-4 to TP301-2 (see Figure 3-2) before troubleshooting this circuit. This provides a common ground across isolation
for the logic probe.
The first program continuously toggles all signal lines labeled ON_TRIG when the program is run. Use the logic probe to
confirm this (see Figure 3-8).
Pulse Mode
U313-4 = HI
U313-14 = toggling
U315-13 = toggling
CHECKOUT TABLE
use scope
U316- U313-
11,12 2,12,15
11=LO Negative
12=Hi pulse
every
0.5ms
1KHz sq. Negative
wave pulse
every
0.5ms
100Hz sq. Negative
wave pulse
every 5ms
11=LO Negative
12=Hi pulse
every 5ms
RESULT
U312- U313-
3 7
Negative TTL Lo
pulse
every
0.01ms
Negative TTL Hi
pulse
every 10 µ s
Negative Negative
pulse pulse
every when
100 µ s
pressed.
Negative TTL Lo
pulse
every
100 µ s
use logic probe
U313- U313-5,8,
17 11,16,19
TTL Hi
TTL Lo Positive
pulse
when
pressed.
Positive Positive
pulse pulse
when when
pressed. pressed.
TTL Hi
U316-
17,19
Negative
pulse
when
pressed.
Negative
pulse
when
pressed.
53