GROUP S.P.A.
MT VCC 01
36
• All the monitors are switched on but none of them has an image /
1. None of the shunts is powered at the + terminal.
2. The coaxial cable of the upright column is interrupted.
To verify this, disconnect the coaxial cable of the video camera and, using an
appropriate tool, measure the resistance of the cable, which should be 75 ohms
(closing resistance on the last shunt).
3. The video camera is not being powered. Check that there is a voltage of 13 V
DC at the + and - terminals of the video camera module.
4. The video camera is faulty. Replace the module with a new one.
• A monitor fails to switch on in response to a call /
1. The 19 V DC voltage is not arriving at the monitor. Check the continuity of the +
and - conductors.
2. The staple has not been put in place between the S and AC terminal of the
monitor.
3. The monitor is broken. Replace it with a new one.
• Autostart of monitors fails /
1. The conductor for the START OUT terminal of the power unit Art. 4594 is not
connected to the monitors.
2. The conductor is not connected to the PS terminal of the power unit.
• No monitors switch on in response to a call /
1. The conductors relating to the + and - terminals in the column are interrupted.
2. The power unit is not supplying 19 V DC voltage to the m and -
terminals. Replace it with a new one.
• The image on the monitor is blurred or doubled /
1. The coaxial cable is not of the 75-ohm type.
2. The distribution of the signal is not correct.
3. The resistance of 75 ohms is not present on the last shunt of the upright
column.
POSSIBLE BREAKDOWNS IN SYSTEMS WITH TWO OR MORE EXTERNAL UNITS
Defect /
Probable fault and solution
• One external unit is always excluded /
1. Check that there is a proper connection of the conductors relating to the
terminals CP1-CP2-CP (IN1)-CP (IN2) of the exchange Art. 4551/B.
2. The exchange Art. 4551/B is not powered.
Make sure there is 12 V AC at the terminals ~L~*.
3. The exchange does not switch because it is defective. Replace it with a new
one.
• Audio-video communication is present with the external unit not calling /
The conductors for the terminals CP (IN1) and CP (IN2) at the exchange Art.
4551/B have been inverted.
POSSIBLE FAULTS FOR ALL TYPES OF SYSTEM
AUDIO PART
Defect /
Probable fault and solution
• The audio of a monitor is poor quality at the external unit /
The microtelephone in question is broken. Replace it with a new one.
• The audio of all the monitors is poor quality at the external unit /
1. The external volume of the porter is set to a level that is too low.
2. The audio porter is defective. Replace it with a new one.
• Reception of a monitor is poor quality /
The microtelephone of the monitor in question is broken. Replace the loudspeaker.
• Reception of all the monitors is poor quality /
1. The internal volume of the porter is set to a level that is too low.
2. The audio porter is defective. Replace it with a new one.
• The audio between the external unit and monitor is poor quality from both sides /
1. The volume level of the porter is set too low.
2. The conductors connected to terminals 2 and 3 are in short circuit.
3. The porter is defective. Replace it with a new one.
4. The power unit is supplying a voltage of less than 10 V DC. Replace it with a
new one.
• There is null reception in a monitor /
The wires of terminals 2-3 and 4 of the monitor in question are not connected or
are interrupted.
• Throughout the whole system there is background noise at 50 Hz /
1. The cables of the system have been channelled over a long section with
conductors that feed high-power alternating charges.
2. Charges have been connected incorrectly on the + - circuit of the porter.
• The electronic call from the external unit is not arriving at a monitor /
1. The call wire between external unit and monitor (terminal S) is interrupted.
2. The call button of the external unit relating to the monitor in question is
defective.
3. The loudspeaker of the microtelephone in question is defective. Replace it with
a new one.
• The electronic call is not arriving at any monitor /
1. The wire that connects terminal C of the power unit to the common element of
the call buttons is interrupted.
2. The call generator of the power unit is defective. Replace the power unit.
• The electrical lock is not working /
1. The wire that connects the electrical lock to the terminal P1 clip of the monitor is
interrupted.
2. The wire that connects the second head of the lock to the terminal ~ * is
interrupted.
3. The section of wires 4 and P1 is inadequate. It is recommended that you
implement the VCC/PF variant on page 65.
4. The power unit is supplying inadequate voltage because more than 4 name tag
bulbs have been inserted in the external unit. It is recommended that you
implement the VCC/EA variant on page 61.
5. The monitor button marked with the key symbol is defective. Replace it with a
new one.
VIDEO PART
Defect /
Probable fault and solution
• A monitor is switched on but has no image /
1. The shunt in question is not powered at the + terminal.
2. The coaxial cable from the shunt to the monitor is interrupted or in short circuit.
3. The output of the shunt in question is defective. Connect the coaxial cable to a
free output or, failing this, replace the shunt.
4. The monitor is broken. Replace it with a new one.
