Multitone RPR750 Series, Руководство пользователя и сервисное руководство, Страница: 40 / 66

TM1215 Iss. 6.0
RPR750
4.5.9 Decoder Alert LED not working
If the LED does not work when the pager is inserted into a charging rack, then check D25,
R52, R54 and the LED itself.
If the LED is not operable during the initialisation sequence, or when the pager receives a
call, verify that IC1 pin 22 or IC12 pin 41(HS) switches to 0V when the LED is active. Also
check the circuit around TR6 and R53.
4.5.10 Decoder does not call
Check that the decoder is enabling the radio via SK1 pin 13 (RXEN) (radio is enabled by
DATAP being set to 3V3). Recovered data should be present on SK1 pin 11 (DATAP).
Using the RF signal generator and a call encoder, send continuous pre-amble to the
pager. Check that the radio is enabled and that the mark-space ratio of the recovered data
is 50:50. If not, check that the fast charge signal (F_CHG, SK1 pin 12) is activated, as the
decoder first samples the data.
If the decoder is receiving continuous pre-amble with a consistent 50:50 mark-space ratio
but will still not call, check the programming of the EEPROM (IC2).
4.5.11 Decoder does not receive Speech Calls
Check that the pager is programmed to receive speech calls and that the loudspeaker is
connected correctly (SK4) and not faulty.
Verify that when a speech call is received, the alert sequence is a maximum of 4 seconds
duration and that there is no escalating alert. When the alert sequence is complete, check
that IC9 pin 5 (EN2) and IC8 pin 2 (EN1) are both set to 3V3. This enables both the
speech pre-amplifier and power amplifier.
Check the speech signal path from SK1 pin 9 (RX_AUDIO), through IC9 (pin 4) and IC8
(pins 7 & 9).
4.5.12 Pager does not record Speech calls
Check for the presence of speech at the junction of C7 & R78. Confirm that the relevant
control signals are present on the speech chip (IC3 pins 8, 9, 10 & 11) and that the
speech signal is present on IC3 pin 20 (AUDOUT) when speech is played back, indicating
that the speech chip is recording correctly. If a speech signal is present, check C6, C43,
R57 and IC8 plus associated circuitry.
4.5.13 Pager cannot be programmed
Confirm that the pager displays entry into the absence/programming, by displaying the
"rack" message programmed into IC2. Verify that the waveform on the programming pin
(PROG) is correct. Typically, the programming input is held low for 18ms, switched high
for 2ms and then returns low. This indicates that the pager has detected the presence of
the rack/programmer and is waiting for a transaction. If the waveform is not present, check
R6, R38, or the programming contact.
If the pager enters absence/programming mode, but does not programme consistently,
check that XL3 is the correct frequency (4.194304MHz).
If the pager responds correctly to the absence/programming commands, but does not
store the data, check the decoder EEPROM (IC2), R9, R75 & R77.
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