Telesto Private Wire, Manual

Page: 19 / 25

5. Servicing
Basic troubleshooting
The Telesto Private Wire Modem is always used as part of a network containing Europa digitisers.
Therefore troubleshooting the Telesto usually involves setting up some combination of
(digitiser,Telesto Modem,central site) equipment under laboratory conditions. In this manner the
commas port of the Telesto Modem can be checked for data continuity which is sufficient proof
that the Telesto Modem is operational.
Before you attempt any troubleshooting check all the connections, batteries and fu ses to rule out
the possibility that the malfunctioning is due to o ne of these items .
Unable to communicate with the Telesto Modem
If the Telesto Modem fails to send any data or, during firmware configuration, the terminal emulator
menu appears inaccessible on power-up, check both the settings of the terminal emulator and the
Telephone Modem PCB firmware. In most cases the cause is either a mismatch in baud rate settings
or the AT command settings in the modem PCB firmware are incorrect.
Disa ssembly and Reassembly
There are two paired boards within the Telesto. The objective is to troubleshoot to the board level
and replace these boards. Attempt to identify the faulty PCB board pair by swapping in the
corresponding board pair from a working unit. The necessary tools are:
1. Phillips screwdriver.
2. Allan key 3 mm for socket head cap screws.
Disassembly Instructions
1. Disconnect all the cables from the Telesto.
2. Remove the screws around the edge of the front plate of the enclosure box and pull
out the electronics tray using two of the face plate connectors..
3. Remove the smaller board by first unscrewing the only screw on the board and then
pulling out the board away from the edge connector.
4. Remo ve the other board by 1.unscrewing the 4 screws to the flex circuits attached to
the front panel connectors , 2. Pulling off each flex circuit from the board connector, 3.
unsrewing the 7 screws holding this board to the chas sis .
Assembly Instructions
The assembly instructions are the reverse of the disassembly instruction. Make sure that the
repaired unit has the same configuration parameter values as the previously faulty unit. Refer to the
as-shipped sheets for the configuration parameters. After power up , check the following:
}
The telephone PCB firmware menu is accessible.
}
The Europa Digitiser is transmitting data.
}
Re-requested packets from the central site are received by the central site.
Telesto Private Wire Modem 15
Servicing