Alfa Romeo alfa 33 Workshop Manual page 150

7. Brush spring inspection
The brush springs should be stiff
enough to assure good brush contact
on the slip rings. If they are not, put
in a new voltage regulator unit.
8. Brush holder unit electrical
continuity inspection
(1) Set the tester to the 52 x 100
scale.
(2) Put one prod on one and then
on the other brush 0.
(3) Put the other prod
terminal 0.
(4) The tester should show current
flow.
( 5 ) I f t h e r e i s n o eletrical conri-
necessary put in new brushes and/or
brush holder.
1 Brushes 2 Terminal
9. Diodes inspection
Bosch Alternator
Set the tester to zero on the fi x
1 scale.
(2) Put the prods on a diode termi-
nals.
Then either:
(infinite resistance).
Inverse current resistance
IGNITION, STARTING, CHARGING SYSTEM
Reverse the two prods The tester
should show the prescribed re-
sistance.
Direct current resistance
R = O+lOa
(2b)The rester shows current flow
and therefore the prescribed resis-
tance.
Reverse the prods and the tester
on the
shows no
resistance).
CAUTION:
All excitation diodes must be tested
in this way.
1 Diode holder plate
(3) If the tester readings are not
those prescribed, put in a new diode
holder plate.
9-2. Ducellier Alternator and Marelli
Power diodes - Bridge direct rest
(1) Zero tester in the a x 1 range
scale.
(2) Carry out direct test of positive
bridge, by setting the tester negative
probe on positive heat sink of bridge
and the other probe, sequentially,
on each end of the three phases of
bridge. Check, on
tance value for direct current is the
required one.
(3) Carry out direct test of negative
bridge, by setting the tester positive
probe on negative heat-sink of bridge
and the other -probe, sequentially,
each
on end of the three phases of
bridge. Check on tester, that resis-
tance values is the required one.
current flow (infinite
that resis-
05-23
Diode resistance in direct conduction
R = 0 -lOa
Power diodes - bridge inverted test
scale.
(2) Carry out inverted-test of bridge
operating as per direct test, by
inverting (in sequence) probes be-
tween positive heat sink and
three phases of bridge when testing
positive bridge.
Inverts (in sequence) probes between
negative heat sink and the three
phases when testing negative bridge.
(3) Verify on tester that current is
not present.
Diode resistance for inverted
conduction
1 Positive hear sink
Negative sink
2
E n e r g i r a t i o n D i o d e D i r e c t t e s t
scale.
(2) Connect tester negative probe
with output of energization diodes
(terminal D+) and second probe
(in sequence) with the three phases.
(3) Verify on tester, that resistance
values for direct current are the
required ones.
Diode R for direct current
Energization Diodes Inverted test
in the ax 100 range
scale.
(2) Operate as per direct test by
inverting tester probes between out-
put of energization diodes (terminal
quence). Verify,. on tester, that
current is not present.
t h e
May 1983