Trigger Functions - Fluke ScopeMeter 123 Service Manual
Industrial scopemeter
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Also See for ScopeMeter 123:
- Service manual (96 pages) ,
- User manual (86 pages) ,
- Getting started (17 pages)
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123
Service Manual
2. Press
7.5.8 Trigger Functions
1. Press
2. Press
3. Press
4. Supply a 1 kHz sine wave of +/- 3 divisions to Input A, and Input B.
5. Check:
6. To test video trigger press
7-14
and select
MEASURE on A:
Verify TP156 for +3.3 ... 0V pulses (repetition rate 100...200 ms):
Zero scale (open input):
Full scale (for example 500 nF):
If not correct, most probably the C-ASIC N101 is defective.
If correct, continue at Section 7.5.8 Trigger functions (pulse width is measured via
the T-ASIC).
and select
MEASURE on A:
and select
INPUT A:
to select the
Press
to select the
I
or
|
INPUT:
A
B
SCREEN UPDATE:
Press
to open the
SCOPE INPUTS
Press
to open the
I
SCOPE MODE:
NORMAL | WAVEFORM MODE:
a. TP156, TP256 for a 600 mV (6 div. x 100 mV/div), 1 kHz, sine wave; the DC
level depends on the trace position.
If not correct, C-ASIC N101/N102 is probably defective.
b. TP321, TP322 for 1.1...1.9V DC (move the trigger level from top to bottom).
If not correct check the PWM circuit, see Section 7.5.8.
c. TP311for a 0...+3.3V, 1 kHz square wave when the trigger level is at the middle
of the trace). Change the trigger level, and verify that the duty cycle of the
square wave changes. If not correct T-ASIC N301 may be defective.
d. TP433 for 0...+3.3V pulses. Pulse width:
4...10 µs for time base 2 µs/div and faster;
>40 µs for time base 5 µs/div and slower; pulse width increases with time base.
e. TP336 for +0.6...0V pulses, TP436 for +3.3...0V pulses; the pulse width is about
40 µs...10 ms.
If not correct, check the RANDOMIZE circuit, see Section 7.5.15.
f. TP437 (SMPCLK) for a 5 MHz (time base ≥ 10 ms/div) or 25 MHz (time base <
10 ms/div) clock signal (3.3V). Check SMPCLK on both sides of R339.
Press
to select the
From the
VIDEO TRIGGER sub
I
SYSTEM:
PAL | LINE:
Press
to open the
SCOPE INPUTS
Press
to open the
I
SCOPE MODE:
NORMAL | WAVEFORM MODE:
I
CAP .
pulse width approximately 30 µs.
pulse width approximately 25 ms.
I
VDC .
I
DC | NORMAL | INPUT B:
menu.
SCOPE INPUTS
menu, and select:
TRIGGER
I
FREE RUN | AUTO RANGE: .
menu.
menu, and select:
SCOPE OPTIONS ...
to select the
SCOPE INPUTS
menu, and select
TRIGGER
menu select:
I
RANDOM | POLARITY:
menu.
menu, and select:
SCOPE OPTIONS ...
I
DC | NORMAL
I
>15HZ
I
.
NORMAL
menu.
I
INPUT:
VIDEO on A...
I
POSITIVE
I
NORMAL
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