ELECTRICAL TROUBLESHOOTING
To ease troubleshooting and repair of electrical problems, it is necessary to have a reliable AC-DC volt-ohm meter
and to have a thorough understanding of the meter and how the paver electrical system operates. Instructions on proper
use of the volt-ohm meter are usually furnished with the instrument and should be read carefully before first use.
Improper use can quickly render the meter inoperative.
The paver electrical system is made up basically of two different voltage supplies: 12 volts DC and 120 volts AC.
The 12 VDC circuit is powered by a 12 volt battery. It is recharged by a Motorola generator with built-in voltage
regulator. (IMPORTANT: Regulator must be an R3-3 or 8RF201 IA with high voltage suppression feature.)
The 120 volt AC circuit supplies power for the screed vibrators and the AC convenience outlet. Output of the AC
generator should be 130 volts - 61 hz with no load applied. Double check the frequency by "taching" the generator shaft.
Speed should be 3660 RPM.
TROUBLESHOOTING METHOD
When the following troubleshooting guide is used, check out the possibility of a defective unit listed by substituting
a spare or by interchanging two identical units to see what change in operation (if any) occurs.
Refer to the schematic diagram when making voltage checks listed in the following charts. Wire numbers referred
to are shown on the schematic. All voltages should be 12 volts DC, unless otherwise specified. A voltage at one point,
but not at the following point indicates that there is difficulty in that area. The numbers listed will suggest the area of
remedy such as loose connections, broken wire, switch in wrong position, relay missing, dirty contacts, etc.
When taking a voltage reading, the first number listed in the chart is for the positive meter lead, and the second
number listed is for the negative meter lead.
For example: Check 17 to 3
Positive meter lead on 17
Negative meter lead on 3
IMPORTANT FIRST STEP!
DC POWER
To begin checks, make sure there is 12 VDC from I to 3. Turn DC power switch to ON and check for 12 VDC from
17 to 3. All circuit breakers are to be ON and 12 VDC should be present on load side of breakers. If not, check for a
faulty breaker.
TROUBLESHOOTING STARTING CIRCUIT
DC power switch held in start position. Track switches in brake position.
Engine does not start
Voltage check:
(1) 13 to 3 - defective start-stop switch
(2) 2 to 3 - defective R2 relay - voltage present indicates faulty starter or starter solenoid
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