Troubleshooting
60
025-9567E
Fault Possible
Cause
Beeper will not sound but
display decimal point
illuminates when beeper would
normally sound.
Encoder Bd. connection bad (J1, or check cable).
Cable between Encoder and Driver Boards bad.
Driver Bd. beeper circuit faulty (J3, C11, LS1).
Decimal point will not illuminate
when time is displayed but
beeper works.
Cable between Encoder and Front Panel boards bad.
Front Panel bd. decimal point driver bad (Q1, R9, R10, DS1).
Encoder does not detect some
or all keypad switches.
Encoder Bd. keypad jumper, JP2, in the disabled position, “A”.
Encoder Bd. keyboard scanner faulty (U17, U8, J2).
Cable between Encoder and Front Panel boards bad.
Front Panel Bd. keys bad.
Time clock gains or losses
time.
Clock Bd. oscillator off frequency (C3, C2, U2, R4, R5, Y1).
Time clock does not remember
time during power failures.
Clock Bd. batteries discharged (BT1, BT2, BT3).
Clock Bd. charging circuit bad (CR3, CR4, R6).
Time will not display with clock
option installed.
Clock Bd. not properly seated on connector J1 on Encoder Bd.
Encoder Bd. chip select circuit bad (U18, U28).
Clock Bd. chip select circuit bad (R1-R2, Q1, U1, CR2, RP1,
CR1).
Encoder apparently does not
retain its programming during
power interruptions.
Severe power spikes on incoming power during power transition.
Encoder Bd. write protection circuit bad (U1-U3, U18, U27-U28,).
The Enable/Disable switch, JP3, may provide additional protection
from power electrical disturbances.
Encoder apparently does not
retain its programming even
when power is continuous.
Severe power spikes on incoming power.
Encoder Bd. EEPROM circuit bad (U1-U3, U18,).
Encoder never emits tone from
tone output.
Encoder Bd. controls bad (U17, U18,).. tone generator bad (all
but relay and channel busy sections of Encoder Bd.).
Encoder always emits tone
from tone output.
Encoder Bd. controls bad (U171, U182,).. tone controls bad
(U3, U4, U8, U2, P5).
Encoder tone output oscillates
at a high frequency (above
audio).
Encoder Bd. output amplifier bad (T1, U5, U6, U9)
Encoder Bd. bias supply bad (U9).
Encoder tone output at too high
or too low an output level or
tones are distorted.
Encoder Bd. tone generators bad (all but relay and channel
busy sections of Analog Bd.).
Encoder tone output off
frequency with 1206 Hz alert
tone or deviation test tones.
Encoder Bd. crystal oscillator off frequency (Y1, U19).
Some or all relays stay closed
or will not close.
Encoder Bd. relay driver bad (U8, U17, U18, U21, U20).
Encoder Bd. relay(s) bad (K1-K10, , P1, P2, P5).
Power input too low.
Programming not performed properly.
Summary of Contents for Model 25
Page 1: ...Model 25 Programmable Encoder Product Manual 025 9567E...
Page 2: ......
Page 16: ...Specifications 8 025 9567E...
Page 36: ...Operation 28 025 9567E RELAY TIMING DIAGRAM...
Page 62: ...Auxiliary Panel Installation 54 025 9567E...
Page 72: ...Troubleshooting 64 025 9567E...