Fig. 7.76. Check of an integrity of conductors of an element of heating of back glass: 1 – щуп the voltmeter; 2 – a direction of pressing by a finger; 3 – a foil; 4 – a path of a heating element
Not to damage a path of a heating element at check, reel up a foil on tips щупов the voltmeter. For check on breakage presence press a foil a finger and spend it on all paths of a heating element (fig. 7.76).
Check of a technical condition
Fig. 7.77. The scheme of check of resistance of paths of a heating element of back glass
Include heating of back glass by the switch and check up pressure on each path in a point located in the middle of glass (fig. 7.77). If pressure on the voltmeter makes approximately 6 In, it is possible to consider a path of a heating element serviceable.
Fig. 7.78. Definition of a site of a point of breakage of a path of a heating element of back glass at the indication of the voltmeter 12 In (the breakage point is noted by a dagger)
If the path is torn off in the middle between the central point and a conclusion «+» (fig. 7.78), the voltmeter will show pressure 12 Century
Fig. 7.79. Definition of a site of a point of breakage of a path of a heating element of back glass at the indication of the voltmeter equal to zero (the breakage point is noted by a dagger)
If path breakage has occurred in the middle between the central point and a conclusion «–» (fig. 7.79), the voltmeter will show the pressure equal to zero.
For search of an exact place of breakage slowly move щуп the voltmeter on a path to a prospective place of breakage. Find a point where pressure appears or reduces to zero. The point in which pressure varies, is a point of breakage of a chain.
Check up an ohmmeter resistance of each path of a heating element between one of conclusions and an average point of a path and between the same conclusion and an average point of the next path. Resistance of section in which there was a breakage, will be twice more resistance of other section. Move щуп a tester on section with rupture to a point in which resistance sharply varies.
Elimination of breakage of conductors of an element of heating
For this purpose it be required to you: a current-carrying paint, a thinner for a paint, a sticky tape, смывка for silicone.
By means of a thin brush wipe a surface has flown down round the found places of breakage of a path, clear this surface смывкой for silicone and paste two slices of a sticky tape along the damaged conductor on either side of from a breakage place so that tape pieces were not imposed on a conductor thread.
Strongly stir up capacity with a current-carrying paint and a brush put it to the place of breakage in three layers with an interval nearby
15 mines (the pasted pieces of a sticky tape serve as a template which provides drawing of a paint coat in width, a comparable path with width of a heating element).
Remove a sticky tape.
Before to include glass heating, allow to a paint to dry up sufficient time (drying time is specified on packing with a paint).
For improvement of appearance of a current carrying path after full drying of a paint (through 24) accurately remove a knife surplus of a paint.