84A-14
CONTROL - SIGNALS
Heated rear screen: Repair
84A
The screen printed heated grid on the inner face of the
window may have an accidental cut, making the affec-
ted part of the circuit useless.
aDetermine the exact location of the cut using a volt-
meter.
Faults such as these can be repaired by using the
heated rear screen varnish available at the. Maga-
sin Pièces de Rechange
I - DETERMINING THE EXACT LOCATION OF THE
CUT USING A VOLTMETER
aSwitch on the ignition.
aSwitch on the heated rear screen supply.
1 - Detection between lines B and A
aConnect the + wire of the voltmeter to the + feed ter-
minal of the rear screen.
aPut the - wire of the voltmeter on a filament at the -
terminal side of the rear screen (line B); the voltage
obtained should be roughly equal to that of the bat-
tery.
aMove the - wire to line A (arrowed line): the voltage
gradually drops.
aA sudden voltage drop indicates that the filament is
cut at that point (carry out this operation for each fi-
lament).
2 - Detection between lines C and A
aConnect the - wire of the voltmeter to the - terminal
of the rear screen.
aPut the + wire of the voltmeter on the filament at the
+ terminal end of the rear screen (line C); the voltage
obtained should be roughly equal to battery voltage.
aMove the + wire towards line A (arrowed line); the
voltage gradually drops.aA sudden voltage drop indicates that the filament is
cut at that point (carry out this operation for each fi-
lament).
II - REPAIRING THE FILAMENT
aClean the section to be treated to remove all dust or
grease, preferably using alcohol or a glass cleaner,
and wipe with a clean, dry cloth.
aTo ensure that the new line is straight, before var-
nishing, apply adhesive tape to either side of the
section to be repaired, leaving the conducting line
exposed.
aBefore using the varnish, shake the bottle to prevent
the silver particles settling at the bottom.
Repair
aCarry out the repair using a small brush, applying a
sufficiently thick layer. If applying successive coats,
allow sufficient drying time between each coat and
do not repeat the operation more than three times.
aIf an error is made with the varnish (runs, smudges,
etc.), it can be removed using a knife point, but only
after several hours, once the product has properly
hardened.
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