TUBE AS. 1247772 - Caterpillar

Checking the Operation of the Amplifier and Pickup
(1) 6V2100 Multitach. (2) 5P9698 Calibrator. (3) 5P7366 Power Cable. (4) Digital Multimeter. (5) Screwdriver. (6) 6V6152 Adapter. Screwdriver (5) should have a blade approximately 150 mm (6 in) long with 6 mm (.25 in) diameter shaft of round bare metal (not anodized or insulated).The 6V6152 Adapter (6) is a phono plug-to-BNC connector. Modifications must be made to the 5P9698 Calibrator (2). Refer to Special Instruction, SMHS7504-01.Checking the 4C6812 Amplifier
(1) 6V6152 Adapter Plug. (2) 5P9698 Calibrator. (3) 4C6812 Amplifier. (4) Connector. (5) 5P7366 Power Cable. (6) Knob. (7) Battery Indicator. (8) No Input Signal Light.1. Install 6V6152 Adapter Plug (1) on the end of the output cable on 5P9698 Calibrator (2). Plug the adapter into 4C6812 Amplifier (3).2. Check the operation of the multitach being used by performing the CHECKING PHOTO OPERATION test procedure contained in Special Instruction SEHS7807. (This is to ensure it is operating correctly on PHOTO operation.)3. Plug connector (4), on the end of the amplifier output cable, into the PH (photo) connector on the multitach. Attach 5P7366 Power Cable (5) to the multitach and to a suitable power source. Refer to SEHS7807.4. Program the multitach for .5 P/REV and to read R/MIN on the PH (photo) input. Turn knob (6) on the calibrator to the 25 Output Hz position.Make sure BATTERY indicator needle (7) is in the white part of the scale. The NO INPUT SIGNAL light (8) on the multitach should go off or become dim, and the number 3000 ( 1) should appear on the digital readout. If this number is correct, the amplifier is working properly. The 25 Output Hz position is the only calibrator position that can be used for this test. Test results should be the same with the amplifier switch in either the INJ LINE or MAG positions. Conduct the test with the switch in both positions to fully test the amplifier circuitry.5. Leave the test equipment connected to the amplifier, and check the pickup as shown in the following procedure.Checking the 1U9139 Pickup
1. Make sure that the pickup is clean and dry. Perform the preceding test procedure "Checking the 4C6812 Amplifier".
(1) 5P9698 Calibrator. (2) 6V6152 Adapter Plug. (3) 4C6812 Amplifier.
(3) Amplifier. (4) Switch. (5) Cable.2. Remove 5P9698 Calibrator (1) and 6V6152 Adapter Plug (2) from 4C6812 Amplifier (3). Make sure that switch (4) is in the INJ LINE position. Connect cable (5) of the pickup to amplifier (3). Leave the multitach programmed to read R/MIN as described in the amplifier test procedure. 3. Install the pickup on the shaft of the 150 mm (6 in) screwdriver as shown. Do not use a screwdriver with an anodized or insulated shaft.The pickup should be positioned approximately 13 mm (.5 in) from the handle. Connect the ground clip to the screwdriver shaft next to (but not touching) the pickup.4. Hold the screwdriver with the pickup by the handle (be careful not to touch the shaft). Hold another screwdriver by the shaft in your