SIGMA AM-255 User Manual
Page 21
6. TROUBLESHOOTING page
18
Model AM-255
To check the charger, disconnect the positive terminal from the battery and J1 from the AM-255
circuit board. Measure the voltage from between the black and red battery wires. It should be at
least 13.5 volts. If it is not then the charger must be replaced.
NOTE:
Do not go on to the next step until the charger is working correctly. Battery voltage must be at
least 12.5 Vdc for the unit to turn on.
6.3. TROUBLESHOOTING
If the unit is totally inoperative, verify that the unit is receiving power throughout the system.
Refer to "Controller Board" Drawing 3 (Appendix F.) for the following procedure.
6.3.1. AM-255 Controller Board:
If the unit has power but still does not operate, test the power to the controller board. Connect
the negative lead of the DVM to TP1 and the positive lead to TP2. The power should be
5 ±0.1 Vdc.