SC4x0 Technical manual
Page 29 of 34
SeaCom
Rev
2.00
12. Simple faultfinding
In this section, examples of simple faultfinding are given to ease installation & servicing on board.
In general there should be time update in the display and a green led inside next to display should be lit.
12.1 No ‘life sign’
When the telephone is connected to power, display should be lit (dependant on dimmer setting) and display should
and real time clock where the ‘:’ separator is flashing each sec.
Check if a green led is lit on the opposite side of J7 on the right side of the PCB when looking from the terminal
side.
Close to the edge of the PCB a green & red led is located. The green indicates 5 volt present, the red indicates
processor reset if lit. The green should be on and the red should be off.
Check power is connected, range is correct and check polarization on the power terminals.
Check the small black box to see if it is warm. Warm means power is flowing through in attempt to maintain
internal 5 volt.
If cold and no green light, no power is generated for internal electronics. If so try to disconnect external speaker if
connected.
If warm, try to disconnect all connections, except power, recycle the power.
12.2 Spontaneous reset
This event should never occur, but if it happens (especially when ambient temperature is hot), remove the jumper
in J7 on the PCB back side or make sure power do not drop below 18 volt.
If this happens during conversation at high volume, or when external speaker in on, check speakers for low
resistance or ground leaks.
12.3 Unable to hang up in hands free mode
If fitted with a handset or if hook switch input is shorted, it is not possible to end current session (conversation)
until handset is relocated in the cradle or input is open, when conversation is carried out in hands free mode.
If no handset is connected, remove any wires connected to hook switch input and recycle power. If input is used
for remote PTT, check setup parameters from the menu system.
12.4 Noisy or scratchy sound quality
Make sure power and line connection is not mixed.
Make sure power is absolutely floating e.i. no common voltage to ground from power supply input filter. This can
be a problem if a separate power supply is used for the SC4x0. If still a problem, connect 0 volt from separate
supply to 0 volt of the supply used to power the exchange. However, it should be possible to run on a separate
supply.
Make sure PE is properly connected.
Make sure no current is flowing via this unit e.i. no ground leak errors.
Make sure nothing is connected to the small PCB connector on the component side next to the internal speaker.
12.5 No direct in, no PA or no command call
Check if direct is disabled in the menu & check jumper is set on line interface unit (older board units)
Make sure the exchange settings are correct for the line in question.
12.6 Dialing problems
Check dial type settings in the menu, especially if pulse dial is used. If using pulse dial, make sure to select correct
type (Swedish or international).
12.7 Low or distorted sound from microphone
Check microphone type, wiring & polarity and make sure gain is set to match the current setup. (can be checked
from menu)
If it is the headset microphone, make sure to select correct type of microphone.
