R.P.S. Corporation MAGNUM series, Service Manual

Page: 92 / 134

Magnum Service Manual V1.0
13
13-14
COMPUTER CONTROL SYSTEM
“( + ) BUSS BAR” does
not power up.
Operate machine
and verify the
customers
complaint.
Is the (+)
buss bar receiving
battery voltage?
Instruct owner on
proper machine
operation
YES
MAGNUM BUSS RELAY DIAGNOSTIC FLOW CHART
1 of 2
Does the
machine turn
on?
Go to the “KEY
SWITCH” diagnosis
section
NO
NO
Using a voltmeter set the meter to DC volts.
Connect the ( -) probe of the meter to the ( - )
buss bar with a clip on your meter probe.
With the positive lead of your meter measure
the voltage at terminal #85 (red wire) on the
buss relay with the key on.
Is there
battery voltage at
this terminal?
Repair break in wiring
between Terminal #85 and
the key switch
NO
Using a voltmeter set the meter to DC volts.
Measure the voltage between terminals #85
(red wire) and #86 (black wire) on the buss
relay with the key on.
Is there
battery voltage
across these
terminals?
YES
Using a voltmeter set the meter to DC volts.
Measure the voltage between terminals #85
(red wire) and the negative buss bar with the
key on.
NO
Using a voltmeter set the meter to DC volts.
Connect the ( -) probe of the meter to the ( - )
buss bar with a clip on your meter probe.
With the positive lead of your meter measure
the voltage at terminal #87 (red wire #) on the
buss relay with the key on.
YES
YES
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