User's Manual

Table Of Contents
Gain access to the power supply used by the VMT (this is likely mounted inside the vehicle). Remove the
four () screws that attach the lid of the power supply to expose the input and output wiring as illustrated in
the diagram below.
Test the input terminals to determine if voltage is being supplied and matches that of the vehicle power
system.
If the voltage supplied does not match that of the vehicle power system, professional attention is needed
to determine why the vehicle power system is not providing the correct voltage.
If no voltage is being supplied, check the fuses on the input cable, replace if they are blown. If the fuses
immediately blow after replacement, determine if the input cable to the VMT power supply has a short
circuit. If there is no short then it is likely there is a problem with the VMT power supply.
If no voltage is being supplied and the fuses are not blown, check the integrity of the input cable for a
break. If there is a break, replace the cable. If not, there is likely a problem with the vehicle power
system that needs professional attention.
If input voltage is being supplied to the power supply, check the output voltage.
If there is input voltage but no output voltage or the output voltage does not match 13.2V DC then the
power supply is likely in need of replacement.
If there is output voltage in the 13.2V DC range then the problem is likely in the cable to the Battery
Adapter or the Battery Adapter itself. Try a known, working Battery Adapter. If that does not work then
it is likely that the cable between the power supply and Battery Adapter is in need of replacement.
A Battery Adapter may be tested by checking the output of the adapter. Note that to rule out problems
with the power supply or cable to the Battery Adapter, a known, working Battery Adapter should be tested
first before testing a suspect Battery Adapter. The two outermost points of a working Battery Adapter
should read approximately 3.9-4.2V DC as illustrated in the figure below.
Confidential: For informational use by Honeywell resellers and customers only
60 | Vocollect Talkman A500 Product Guide