MITSUBISHI ELECTRONICS AMERICA, INC.
ST200 Series Technical Support Manual
80
January 2000
9.2 Trouble Checklists
This section has been developed to solve a variety of product and system problems. These
checklists can be used with land mobile, transportable and fixed site MT configurations to
resolve most common problems. If you need further assistance please contact the MSAT Service
Center at (800) 966-6728.
Problem: The MT will not power on or off
The most common cause of MT power on failures is a defective power supply in the transceiver
unit (CTU), which can only be repaired at the Mitsubishi MSAT Service Center. Other possible
causes may be ruled out by following the checklist below.
What to Check
What to do
1. Does the MT turn off while starting the
engine?
This is a standard feature of the MT.
2. Are shaded blocks displayed on the
handset?
Shaded blocks may indicate a transceiver unit
failure or a bad connection.
3. Is the power in the power supply or battery
sufficient?
Change power supplies or charge the battery.
4. Are the connections good?
Make sure the connections between the CTU
and BSU, AU, handset and vehicle battery are
tight and not damaged or corroded. Make sure
the handset is not attached to the PTT port.
5. Are cables defective?
Check for breaks in the cable.
6. Fuse in power cable.
Replace defective power cable fuses.
7. Fuse in the vehicle or power supply.
Replace defective fuses.
8. Does the MT respond to the handset
keypad?
Lack of response to the keypad may indicate
software corruption.
9. Is the ST251 MT lid open?
Lid must be open for the ST251 to power up.
Problem: MT fails commissioning
Dealers and MT users who do not commission MTs regularly sometimes find the process
difficult. As long as the commissioning instructions are followed carefully and the process is not
rushed, it is simple and easy.
There are several common reasons for failure of the commissioning process. The most common
reason is that the MT has not been programmed with the correct SASK or the service provider
has not properly activated the account. Also, because the buttons on the Mitsubishi handset
keypad are small and recessed, holding down the CLR button while entering the program mode
entry code in order to get into program mode is difficult for some people and requires several
attempts. Other possible problems can be ruled out by following the checklist below.
