8.3 Testing the main transformer
8.3
Disconnect the mains plug
Disconnect secondary
terminal 4 of the main
transformer from the rectifier
Connect the charger to the
mains via the isolating
transformer
Set the selector switch to
"
12 V"
Secondary
voltages in accordance
no
with table
?
yes
Set the selector switch to 0
Disconnect the mains plug
8.4
Measured values (no-load)
Contact
7 780 100 006
1/3
230 V
4/5
8.25 V
4/6
14.0 V
4/7
25.5 V
English
Avoid short circuits !
Proceed with caution
when conducting
measurements on the
secondary terminals of
the main transformer!
Set the selector switch to 0
Disconnect the mains plug
Clearly identify and
disconnect the connection
leads on the main
transformer
Remove the main
transformer (4 screws)
Fit a new main transformer
Connect the connection
leads as marked
9
7 780 100 008
230 V
rms
rms
7.2 V
rms
rms
12.8 V
rms
rms
23.3 V
rms
rms
8.4 Testing the rectifier
8.4
Disconnect the mains plug
Connect the test resistor
7Ω directly to the outer
rectifier
plates (+/–)
Connect the charger to the
mains via the isolating
transformer
Set the selector switch to
"
24 V"
Voltage measurements
U1
U2
V=
V=
U4
U3
V=
V=
R
L
approx
. 7Ω
U
to U
1
4
Voltage deviation
no
< 1 V
?
yes
Set the selector switch to 0
Disconnect the mains plug
8.5
15
Set the selector switch to 0
Disconnect the mains plug
Clearly identify and
disconnect the rectifier
terminals
Remove the temperature
switch and shunt
Exchange the rectifier
(2 screws)
Connect the connection
leads as marked
Fit the temperature switch
and shunt
9