GAI-Tronics 751-901 SmartSeries Speaker Amplifier - Manual (Page 10)

Pub. 42004-659L2F
751-901 SmartSeries ® Speaker Amplifier P AGE
9 of 11
f:\standard ioms - current release\42004 instr. manuals\42004-659l2f.doc
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How to Diagnose Assembly Faults
When the assembly is in an ADVANCE system that includes a vacuum fluorescent display (VFD), faults
may be automatically detected, transmitted to the MCU in data messages, and displayed or printed. Fault
messages and possible solutions for their causes are described in the table below.
Fault Message Cause and Effect Possible Solution
Watch-Dog timer
Processor has Reset
xd times
(Where x is the
decimal number of
times the watchdog
timer has reset the
processor.)
Cause—The watchdog timer has forced the
processor to reset. This occurs when the reset
pins (J2) on the FSK/
P PCBA are temporarily
shorted or when the watchdog timer does not
receive regular status pulses from U4 on the
FSK/
P PCBA.
Effect—The processor maintains a count of the
number of resets. If the station is powered
down, the count restarts at zero. The station
still amplifies incoming pages. For the fourth
and subsequent resets, the count is zero.
 Verify that the reset
pins 2 and 3 (J2) on the
FSK/
P PCBA are not
shorted.
 Replace the FSK/P
PCBA.
Supervised Audio
Path
Page Amp
Cause—The station failed its internal speaker
amplifier health check.
Effect—The station disables the speaker
amplifier health-check function after the first
failure.
 Replace the Speaker
Amp/Power Supply
PCBA.
 Replace FSK/P PCBA
Supervised Audio
Path
Speaker Voice Coil
Cause—The station is detecting no ambient
noise at the speaker or is detecting an ambient
noise lower than the configured failure
threshold. This may occur if there is a fault in
the speaker wire or a fault at the voice coil.
This also may occur if the ambient noise at the
speaker is too low, as is the case in a quiet
room.
Effect—The station continues measuring
speaker ambient noise. When acceptable noise
levels are subsequently measured, a restore
message is sent to the MCU.
 Verify that the speaker
wire is connected and
intact.
 Verify that the voice
coil is connected and
intact.
 Replace the Speaker
Amp/Power Supply
PCBA.
 Replace FSK/P
PCBA.
Polled device Cause—This message is output by the MCU
when it loses communication with the station.
This may occur if there is a fault in the page
line, if the station is powered-down, or if there
is some fatal malfunction within the station.
Effect—The MCU continues to attempt
communication with the station. When
communication is resumed, a restore message is
sent to the MCU.
 Verify that the page line
is connected and intact.
 Verify that the station is
installed correctly.
 Replace the FSK/P
PCBA.