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Maintenance
7–12
VITS100 NTSC VITS Inserter Instruction Manual
Figure 7–3: Diagnostics switch, S8
To run a user diagnostic (including those run at power up), set S8 to the position
for the desired diagnostic and then cycle the power off and on. The processor
then runs through the power up process, polls the diagnostic port, and runs the
selected diagnostic.
Table 7–3: The User Diagnostics
Diagnostic
Switch (S8)
Setting
Test Description
Test Result
Indication
0 None Normal setting, no diagnostics.
1 Not Used
2 RAM Tests Writes to and then reads from all
PRAM locations in the genlock IC
(A1U29 ); compares “read” data to
written. Writes to and reads from all
sample RAM locations in the genlock
IC; compares read data to written.
This test runs once during power-up
diagnostics.
In the event of fail-
ure, the UNLOCKED
LED lights and the
instrument does not
lock to program (in-
put) video.
3 ARCTAN PROM
Test
Computes the checksum of the
arctangent EPROM (A1U33) and
compares the value with one that
has been written in the processor
EPROM. When selected through the
diagnostic switch, the test runs
continuously. During power up
diagnostics, it runs once.
In the event of fail-
ure, the UNLOCKED
LED lights and the
instrument does not
lock to program (in-
put) video.