Bridge Test - Graco A Series Instructions-Parts List Manual

Remove the bridge from the pressure control box and
perform this test to determine if the bridge is functional.
See BRIDGE RECTIFIER REPLACEMENT , page 27.
Use a continuity tester, such as multi–meter set on the X1
ohms scale.
All tests must be performed. If the bridge fails even one
test, it must be replaced.
Fig 23–1 shows the position of the wires on the bridge.
Using the chart at the right, connect the meter wires as
indicated by the black dots for each test, and then check
the continuity.
In Tests 1, 2 and 3, there should be NO continuity.
In Tests 4, 5 and 6, connect the + and – meter wires as
indicated, check continuity , then switch the meter wire
connections and check continuity again. You should get
NO continuity one way and YES continuity the other way.
In Tests 7 and 8, connect the meter wires as indicated by
the black dots. Touch the indicated "G" wire to one meter
wire, and then to the other. You should get NO continuity
one way and YES continuity the other way.
AC1 G1
AC2 G2
Fig 23–1

BRIDGE TEST

–
+
BRIDGE WIRES
G2 G1 –
NO
NO
NO
YES
NO
YES
NO
YES
NO
YES
OR
NO
YES
OR
NO
+ AC1 AC2
TEST 1
TEST 2
TEST 3
TEST 4
TEST 5
TEST 6
TEST 7
TEST 8
307–958