5
947120M
TABLE 1
TROUBLESHOOTING CHART
PROBLEM
PROBABLE CAUSES AND CORRECTIONS
No Side Tone
Check "A" battery connections, polarity and voltage.
No Dial Tone
Check "A" and "B" battery connections, polarity and voltage
No Volume to Speaker
1.
Check phone to speaker control.
2.
Check* for audio present at tip, ring input BL/WH, WH/BL pair.
3.
Check* for audio at signaled speaker pair at 66 block.
4.
Check* for audio at input of speaker.
No Volume to Phone
1.
Check speaker to phone volume control.
2.
Check wiring to talkback speaker.
3.
Remove all connections to inhibit pin and verify.
Hum Heard at Phone
1.
Check wiring to speaker.
2.
Possible magnetic interference from power supply - relocate unit and
cables at least 18" away.
3.
Check for noisy "A" battery.
No Speaker Cancel
1.
Verify ground present at phone side of at least (2) 10K ohm resistors.
NOTE: Do not apply ground directly to inhibit input.
R. F. Interference
1.
Strap from V-119 chassis to A GND and B GND on punchdown block.
Continue strap to earth or water pipe ground.
2.
Connect .05 mfd ceramic disc capacitor from each side of each speaker
pair to B ground on punchdown block.
Crosstalk Between Zones
1.
Failure to use twisted pair wiring.
2.
Load speaker output pair at block by connect a 1/2 watt 47 ohm resistor
across output pair.
*Use lineman's test set (Butt set)
