VESPA LX 4T USA Workshop Manual page 54

Electrical system
3) Battery fails to charge
4) Turn indicators failure
The regulator is provided with earth supplied from the electrical equipment, therefore the regulator body
does not supply earth to the internal circuits. Check the insulation between each terminal of the regulator
and its body, using the specific tester.
2) LIGHTS AND CHOKE DEVICE NOT OPERA-
TIONAL
Remove the plastic door on the leg-shield to reach
the voltage regulator, start the engine and let it run
at idle.
Place the positive terminal from the tester on ter-
minal no. 1 (yellow-black wire) and the negative
terminal on terminal no. 2 (black wire); check for
voltage.
If voltage is present, check the wiring connecting
the headlight switch to the voltage regulator, and
the operation of the light switch.
If no voltage is found, put the negative terminal to
earth; if this provides voltage readings, check the
earth wire on the regulator; otherwise, replace the
regulator as certainly faulty.
As a last test it is possible to check the output volt-
age from the stator:
-Detach the regulator connector and interpose the
tester between the Gray-Blue wire (4) and earth
(see figure).
-The voltage output at 2,000 rpm must be approx.
25 - 35V If this test gives no voltage readings too,
replace the regulator as certainly faulty.
N.B.
TO MEASURE THE ABOVE VOLTAGE USE AN ANALOGUE
TESTER THAT CAN MEASURE ALTERNATING VOLTAG-
ES AND KEEP THE ENGINE AT IDLE TO HAVE AN ALTER-
NATING VOLTAGE OF A FREQUENCY AS CLOSE AS
POSSIBLE TO 50HZ SO AS TO DETECT THE EFFICIENT
VOLTAGE VALUE SUPPLIED BY THE REGULATOR
(ABOUT 12V).
ELE SYS - 54
LX 4T USA