Chapter 8 387
ADC/Interface Section
Triggering or Video Gating Problems
e. Set the pulse/function generator to NORMAL mode with a duty
cycle of 50% and a frequency of 10 Hz.
f. Press the following keys on the oscilloscope:
CLEAR DISPLAY
off frame axes grid .....................................highlightgrid
connect dots off on ......................................highlighton
TRIG
source 1 2 3 4 ................................................ highlight4
level ........................................................................... 2V
TIMEBASE
TIMEBASE ...................................................... 50ms/div
CHAN
CHANNEL 1 2 3 4 off on
highlight CHANNEL 1 on
set V/div to 0.2 V and offset to 0.6 V (10:1 probe used)
highlight
CHANNEL 4 on
set V/div to 2 V and offset to 0 V
DISPLAY
DISPLAY norm avg env ........................... highlightnorm
g. Using a 10:1 probe connected to channel 1 of the oscilloscope,
check for activity at pins 10 and 13 of A3U617.
h. If either pin (or both) show no activity, check for activity at pin
21 (LTIMER) of A3U617.
i. If LTIMER is not active, troubleshoot the Interface Strobe Select
circuitry (block K).
j. If there was activity at pins 10 and 13 of A3U617, suspect
A3U616.
To Next Page
Loading...
Need help?
General
