MEASURING AR-HARVESTER HEAD 2192535 - Caterpillar

If the voltage is still less than 17 VDC, the auxillary distribution board is probably good and the main distribution board must be checked. Stop the magneto and move the auxillary distribution board to one side using care to be sure the spacer posts do not cause a short circuit on the bottom of the auxillary board. Disconnect the white/red wires from terminal (C-2). Check the voltage between the white/red wires and terminal (C-1) with the magneto running at 30 rpm.If the voltage is now between 17 and 24 VDC, a trigger SCR or a potentiometer on the distribution board has a defect. Install a new distribution board and do the FAILURE ANALYSIS again to be sure the problem has been corrected. If the voltage is still less than 17 VDC, stop the magneto and disconnect the white/green wire from terminal (C-1). Check the voltage between the white/green wire and the magneto ground with the magneto running at 30 rpm. If the voltage is at least 25 VDC, the power board has a defect. Install a new power board and do the FAILURE ANALYSIS again to be sure the problem has been corrected. 4. For 6 and 8 cylinder magnetos, put the negative probe of the multimeter on terminal (C-11). Put the multimeter switch to the 10 VDC scale and put the positive probe on terminal (C-1). Turn the speed control knob until the magneto is running at 1200 rpm.If the voltage is between 2.15 and 4.5 VDC, the magneto bias is good. (Go on to step 6.) If the voltage is less than 2.15 VDC, stop the magneto and remove the white/yellow wire from terminal (C-11). Put the negative probe on the white/yellow wire and the positive probe on terminal (C-1). Turn the speed control knob until the magneto is running at 1200 rpm.If the voltage is between 2.50 and 4.9 VDC stop the magneto, remove the protection plate for the pulser coil and inspect the pulser coil. (When the magneto is in the "flux-lock" position the straight edge of the pulser rotor must be in the center of a pick up (4) on the pulser coil.) If the straight edge of the pulser rotor is not in alignment with the center of a pick up, loosen the retainer nut and make adjustments to the position of the rotor. Check the timing and change if necessary. Do the FAILURE ANALYSIS again to be sure the problem has been corrected. Open the heat sink section and disconnect the gray wires from terminals (B-3) and (B-4). Put the multimeter switch to the 30 VAC scale. Check the output voltage of the bias generator by connecting the multimeter probes to the gray wires with the magneto running at 1200 rpm.If the voltage is less than 7 VAC, install a new generator coil. Do the failure analysis again to be sure the problem has been corrected. If the voltage is between 7 and 18 VAC, the generator bias is good and