Teletype SA110 Checkout And Troubleshooting page 8

SECTION 578-200-300
SA110 PARITY FAILURE DETECTOR TROUBLESHOOTING CHART
NO. TROUBLE INDICATION
ANALYSIS AND RECOMMENDED ACTION
1.
Nothing is received by terminal a.
Check SA110 data input and output terminals for loose connections
from SA110 (terminal runs closed).
or connections made to wrong terminals ( 8716WD or 8717WD).
Correct any faults found.
b.
If data connections arc good, turn PARITY CHECK switch to ON and
request a long message transmission from another station. Measure
the voltage between slip connector terminals 2 and 3 (EIA input) or
2 and 1 (all other inputs) on card MC405 while the message is being
received. If the voltage between terminals 2 and 3 or 2 and 1 is a
steady 0 volt, check the contacts and wiring on the PARITY CHECK
switch (8566WD or 8567WD). Repair any faults found.
c.
If the volrage measured in step b fluctuates near 0 volt (positive
or negative, but not a steady -3 to -25 volts), measure the voltage
between slip connector terminal 2 and post 18 on card MC405 while
a message is being received. If this voltage is a steady +6 volts,
the input amplifier (8538WD) is defective. Repair it or replace
card MC405 (TP322405).
d.
If the voltage measured in step c fluctuates near+ 3 volts
(from Oto +6 volts), measure the voltage between slip connector
terminal 2 and post 16 on card MC405 while a message is being
received. If this voltage is a steady 0 volt, card MC402-04 is
defective. Repair or replace card MC402-04 (TP322402-04).
e.
If the voltage measured in step d fluctuates near +3 volts
(from Oto +6 volts), measure the voltage between slip connector
terminals 2 and 10 (EIA output) or 2 and 12 (all other outputs) on
card MC405 while a message is being received. If this voltage is a
steady -8 (±2) volts (EIA), +8 (±2) volts (signal line), or 0 volt
(lOlC or 105A data set), the output amplifier (8538WD) is defective.
Repair it or replace card MC405 (TP322405).
f.
If the voltage measured in step c fluctuates near 0 volt (EIA) or +4
volts (all other outputs), check the contacts and wiring on the
PARITY CHECK switch (8566WD or 8567WD) and connections to the
terminal. Repair any faults found.
2. Terminal runs open when SAll0 a.
Check connections between terminal and SA 110 to be certain that all
PARITY CHECK switch is ON.
wires were installed at the correct locations (8716WD or 8717WD) and
that no connections arc loose. Correct any faults found.
b.
Check fuses Fl and F2 between cards in SA 110. Re plan· any bad fuse.
Make certain SAl 10 is securely plugged in.
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