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BASIC BOARD MODULE (BBM)
7-6
3. If display shows:
a. "A" - both receive messages passed.
b. "1" - main receive message failed.
c. "2" - secondary receive message failed.
7.4.7 SYSTEM SWITCH EQUALS "7"
1. Closes the relays on the telephone line personality
card to connect the telephone line and the Silent Slot
of the VTM Bus to the main transmit audio.
7.4.8 SYSTEM SWITCH EQUALS "8"
1. Turns on the FSK transmit for the 1200 Hz tone.
2. Turns on the FSR gate to the main transmit audio.
7.4.9 SYSTEM SWITCH EQUALS "9"
1. This allows the TIM-DID to answer an incoming
call and to provide a System Alignment Tone to the
telephone line. This allows the DID to have the
hybrid adjust circuit tuned.
7.5 TROUBLESHOOTING
This section provides some basic hardware trou-
bleshooting procedures. These procedures follow the
Test Tasks (See Section 7.4).
7.5.1 TEST "1"
System Alignment Tone Test.
1. The Test Tone of 1004 Hz should be -3 dBm ±1 dB
at U19, pin 2 (CODEC IC).
2. The tone should pass through op amp U32A. Adjust
R83 for a level of -6 dBm ±0.5 dB at TP3.
3. The tone should pass through transmission gate
U31B with less than 0.25 dB of loss. This gate
should have a high on U31B, pin 5 (control pin),
from U46A, pin 1.
The transmission gates U30A, U30B, U31D,
U31C, U57C and U31A should be off ( < 1V on the
control pins). U46, pins 5, 3, 9, 11 and 13 should be
low ( < 1V). U6, pin 15 should be high, > 4.5V.
4. The tone should pass through the op amp 600 ohm
line drivers, U28A and U28B. Adjust R44 for a
level of -12 dBm ±1 dB at J12. The level should be
-12 dBm ±1 dB across the Tx line.
TIM With DID Personality Card (-660)
1. The Test Tone of 1004 Hz should be -3 dBm ±1 dB
at U19, pin 2 (CODEC IC).
2. The tone should pass through op amp U32A. Adjust
R83 for a level of -6 dBm ±0.5 dB at TP3.
3. The tone should pass through transmission gate
U31B with less than 0.25 dB of loss. This gate
should have a high on U31B, pin 5 (control pin),
from U46A, pin 1.
4. The tone should pass through the op amp 600 ohm
line drivers, U28A and U28B. Adjust R44 for a
level of -8 dBm ±1 dB at J12.
5. The tone should pass through P33, pins 5 and 6 to
the personality card to R263 and transformer T201,
pins 10 and 9, via the jumper. Relay K204 should
be active
( < 1V on pin 8), U208, pin 16 should be high ( >
4.5V).
6. The audio should pass through to the line with a
level of -12 dBm ±2 dB across a series 600 ohm and
2.2 microfarad capacitor.
TIM With 2WY Personality Card (-670)
1. The Test Tone of 1004 Hz should be -3 dBm ±1 dB
at U19, pin 2 (CODEC IC).
2. The tone should pass through op amp U32A. Adjust
R83 for a level of -6 dBm ±0.5 dB at TP3.
3. The tone should pass through transmission gate
U31B with less than 0.25 dB of loss. This gate
should have a high on U31B, pin 5 (control pin),
from U46A, pin 1.