Voltage through the lamp is supplied to the collector plates and to the armature core. The burning of the lamp indicates a short circuit of the winding or collector plates with ground. When checking with a megger, it should show a resistance of at least 10 kOhm. Replace the anchor that has a short to ground.
Using a special device, check for short circuits between the armature winding sections or collector plates, and for breaks at the soldering point of the winding section leads to the collector plates.
Inspect the working surface of the collector. If it is dirty or burnt, clean it with a fine-grained sandpaper.
Drive unit. The starter drive must move freely, without noticeable jamming, on the shaft. The gear must rotate relative to the drive shaft in the direction of rotation of the armature under the action of a torque of not more than 0.27 Nm (2.8 kgf cm). The gear should not turn in the opposite direction. If there are nicks on the engagement part of the gear teeth, then grind them with a fine-grained emery wheel of small diameter.
If drive parts are damaged or severely worn, replace the drive with a new one.
Covers and supports. Check the cover on the drive side for cracks. If they are, replace the cover with a new one. Check the condition of the cover shells and shaft bearings. If they are worn, then replace the liners or bearings and covers assemblies with liners.
Brush holder. Check the reliability of the brush holder on the back cover. The brushes must move freely in the grooves of the brush holders. The distance from the brush outlet to the working edge must be at least 3.5 mm. If the brushes are worn out more, they must be replaced.
Traction relay. Check the ease of movement of the relay armature. Check with an ohmmeter whether the contact bolts of the relay are closed by the contact plate. If the contact bolts do not close, then disassemble the relay and clean the contact bolts with fine-grained sandpaper or a flat velvet file.
Reducer. Check the condition of the gear teeth and needle bearings of the planetary gears, replace damaged gears and bearings.