Important: Disconnect wires between the battery, the alternator
and the regulator only when the engines is not runnig.@@L
If the battery is recharged in the car with a charging device
remove the plus and minus cables from the battery first.@@L
When applying the electric arc welding process connect the
earth terminal of the welding equipment direct to the part of the
car to be welded.
The battery charge telltale serves for preexcitation of the
alternator.

To check the regulator disconnect B + (red cable) on the
alternator with the engine not running.
Connect voltmeter to B + and D - .Start engine.
Shortly after the regulator cuts in the voltage must be
13.5 ÷ 14.2 V.

Important: If this value is not reached or if it is exceeded,
measure voltage on D + /61 (use terminal on regulator-blue cable - as
this is more easily accessible) and D-under the same conditions.

The difference in voltage can also be measured direct between
D + and B + by means of a voltmeter with a measuring range of approx. 3 V.
If the voltage difference is up to 0.5 V there is a defect in the regulator.
If the voltage difference is between 1.5 V and 4 V there is a defect in the
alternator.
To check the battery charging current connect ammeter A (range of
measurement: 60 Amps) to the B cable.
Connect a load resistor providing a load of up to 60 Amps parallel to
battery B.
Connect voltmeter V to terminals D + and D - on the alternator.
Run engine at a speed of approx. 3000 rpm.
Set to maximum current¹) on the slide resistance, and read regular
voltage under load¹) on voltmeter.


¹ See specifications

If the battery telltale lamp is illuminated while the ignition is
switched off and if the lamp goes off when the ignition is switched
on, the battery will be discharged by the plus diode - which does not
have a locking effect anymore.
In this case disconnect red cable B + on the alternator and the
regulator by pulling off the plug at once. If the battery charge is
sufficient the car can still be driven.
Check with the Bosch ignition oscillograph EFAW 110. The
special sender cabe EFEA 22 Y 66 Z is also necessary in this case.
Alternator in perfect condition.

One exciter diode interrupted.

One plus diode interrupted.

One minus diode interrupted.

Short circuit of an exciter diode.

Short circuit of a positive diode.

Short circuit of a negative diode.

Phase error.

Phase error and short circuited negative diode.

Diodes with altered characteristic.
Note! Variations below 50% are permissible.
In the case of larger variations the defective diode must be
replaced.