Tektronix VITS 200 Instruction Manual page 172

Table 7–1: Inserter Board Diagnostics
S8
Setting Test
0 None
1 Do not use
2 RAM Tests
3 ARCTAN PROM
Test
4 CTC Test
5 Do not use
6 Do not use
7 Port Test
8 VCO DAC Test
9 Sampler Test 1
A Sampler Test 2
B Do not use
C Do not use
D Do not use
E Do not use
F Do not use
VITS 200
Description
Normal Genlock setting, no diagnostics.
This position is not used for the VITS 200.
Writes to and then reads from all the mP RAM
locations in the genlock IC (A1U29 ), and
compares the two. Writes to and reads from all
sample RAM locations in the genlock IC, and
compares the two. During power-up diagnostics,
this test is run once.
Computes the checksum of the arctangent
EPROM (A1U33), and compares the value with
one that has been written in the processor
EPROM. This test is run continuously. During
power up diagnostics, this test is run once.
This test sets up the Counter Timer Chip (CTC)
(A1U30) as timers, and checks to see that they
can generate interrupts. Each of the CTC's four
sections are set up to interrupt after 4096
processor clock cycles. If any of the CTC's
sections have not interrupted within the allocated
time, the test fails. During power-up diagnostics,
this test is run once.
This position is not used for the VITS 200.
This position is not used for the VITS 200.
Counts from 0–255 on the I/O ports of the the
microprocessor system. This is the ED0-ED7
bus.
Generates a field rate ramp at the VCO DAC for
checking the genlock DAC. This ramp may be
viewed at A1J12–2.
Acquires a sample of sync and burst via the
genlock input, and then reconstructs the sampled
sync and burst at equivalent time through the
VCO DAC A1J12–2. A1C46 (schematic 6) must
be shorted out for this test.
Sets up the genlock acquisition system to sample
incoming video continuously, for checking
acquisition timing.
This position is not used for the VITS 200.
This position is not used for the VITS 200.
This position is not used for the VITS 200.
This position is not used for the VITS 200.
This position is not used for the VITS 200.
Test Result Indication
NA
NA
On failure, lights the UNLOCKED LED, and the
instrument will not lock to program video.
On failure, lights the UNLOCKED led, and the
instrument will not lock to program video.
On failure, lights the UNLOCKED led, and the
instrument will not lock to program video.
NA
NA
Used to check the data and load paths connected
to the I/O ports. ED0ED7 bus should show a
binary count pattern when viewed with a scope
Used to check the VCO DAC and Integrator.
Used to check the Genlock Acquisition circuitry.
Use a scope to check genlock timing pulses on
CTC A1U30 pins 20–23. Trigger on input video.
NA
NA
NA
NA
NA
Maintenance
7–5