21A1. General. This chapter contains trouble shooting information and tests which can be made to help determine the causes of some of the troubles that may develop   in the log system. Each symptom of trouble is followed by a list of the possible causes, and a list of the possible remedies to correct the trouble.
1. Speed pointer is sluggish, does not readily respond to changes of ship's speed; or speed indication is in error. 1a. Clogged rodmeter, clogged hose, or clogged pipe fittings of manometer.

1b. Friction in manometer shaft at gland, rack teeth, or rack roller.

1c. Friction in transmitter shaft bearings, gearing, or self-synchronous transmitter bearings.

1d. Transmitter dial not on zero when bypass valve is opened.

1e. Friction in master speed repeater, self-synchronous repeater, follow-up motor, or in cam roller carriage.

1f. Friction in self-synchronous speed repeater.

1g. Master speed repeater contacts dirty or out of adjustment.

1a. Blow out rodmeter. (See Section 20B2.) Vent thoroughly after reinstalling hose. (See Section 19A3.)

1b. Work grease into gland by turning down grease cup while rotating the shaft slightly. Open gear chamber, and clean shaft, gland, gearing, and roller.

1c. Clean and oil bearings where required. See that miter gears run true, and do not bind.

1d. Set the dial to zero with the bypass valve open. (See Section 20E1.)

1e. Clean and lubricate bearings and gearing. With pointer of master speed repeater at about 20 knots, lift cam roller carriage carefully by hand to check it for free operation on guide rods. Do not allow carriage to drop on the pointer cam.

1f. Clean and oil repeater bearings.

1g. Clean and adjust contacts. See Figure 18-12 for contact clearance.


2. Log does not indicate speed when rodmeter is lowered with ship underway. 2a. Valve positions incorrect. (Transmitter dial will not indicate.)

2b. 1Y circuit open. (Transmitter dial will indicate speed; but speed repeater will not indicate.)

2a. Set valves to operating position (Figure 19-4).

2b. Close 1Y circuit. Check fuses and circuit.

3. Transmitter does not record distance when rodmeter is lowered with ship underway. 3. Integrator timer not operating. 3. Check circuit supplying motor. If a.c. unit, check synchronous motor and starting condenser, or internal gearing. If d.c. unit, press starting button until unit picks up cycle of operation. Replace entire d.c. clock unit if feasible, returning defective unit to manufacturer for repair.
4. Speed reading correct but transmitter distance is in error; checked by securing transmitter dial at a fixed reading and allowing integrator to operate for a fixed time. 4a. Sweep of integrator operating arm not timed correctly. Timing counter showing incorrect number of strokes per hour.

4b. Integrator mechanism binding (causes under-reading), or too free (causes over-reading).

4c. Transmitter distance counter defective.

4a. For a.c. units, check constant frequency supply (must be 60 cycles). Clean and oil gearing and cam. Oil motor bearings. For d.c. units, clean and reset, or replace motor contacts. Check escapement and replace if necessary. (See Section 20E2.)

4b. Clean smooth faces of integrator wheel. Clean friction brake and rear brake block by slipping paper between brakes and wheel. Brake tension should be 5 ounces measured at notch of brake spring. Clean pawls. Do not oil pawls or brake surfaces. Replace worn pawls. Check shafts, gears, and bearing surfaces for proper operation.

4c. Replace counter.


5. Distance repeater counters do not record distance properly, although transmitter is recording distance correctly. 5a. Distance repeater circuit open.

5b. Distance contacts in transmitter, dirty, off adjustment, or burned.

5c. Star wheel worn, or loose on countershaft.

5d. Counter magnet armature or linkage sticking. Counter circuit open.

5a. Check switches and fuses.

5b. Clean contacts. Readjust, or replace if necessary. (See Section 20E3.) Keep oil away from contacts.

5c. Tighten or replace star wheel.

5d. Remove cause of sticking. Check magnet circuit.

6. Integrator mechanism operating, although ship has stopped. 6. Transmitter dial not on zero, integrator arm can move slightly registering distance on counter. 6. Set transmitter dial on zero with by-pass valve open. (See Section 20EL)
7. Rodmeter cannot be raised with chain hoist. 7. Rodmeter is bent. 7. Replace with spare rodmeter. (See Section 2005.) Salvage bent rodmeter, and straighten if possible.
8. Rodmeter gland leaks excessively. 8. Packing gland loose or worn. 8. Tighten packing gland nuts. Repack if necessary.
9. Manometer shaft gland leaks excessively. 9a. Insufficient grease in shaft seal.

9b. Shaft worn.

9a. Refill grease cup and force grease into seal.

9b. Replace shaft. Use oversize shaft if necessary.

10. Erratic speed indications on transmitter dial. 10a. Grease in shaft gland hardened. Salt crust on rack and pinion teeth.

10b. Rack roller binding. Roller worn flat.

10a. Clean shaft, gland, gears, and rack.

10bb. Clean roller and pivot. Replace roller.

11. Transmitter speed dial cannot be moved below zero, with by-pass valve opened. 11. Float is hitting float chamber bottom due to insufficient mercury in chamber. 11. Add enough mercury to manometer to allow dial to be turned 1/4-inch below zero. Mercury should then raise float until dial reads zero. (See section 20D3.) Reset zero by means of fork adjustment if necessary.


12. Master speed repeater speed indication does not agree with transmitter speed indication. 12a. Master speed repeater not correctly calibrated.

12b. Follow-up contacts dirty, or set too far apart.

12c. Cam roller carriage binding. Cam roller sticking.

12a. Recalibrate master speed repeater. (See Section 20F2.)

12b. Clean and adjust followup contacts. (See Figure 18-12.)

12c. Clean carriage rods and bearings.

13. Speed and distance indicator speed does not agree with transmitter and master speed repeater indications. 13. Self-synchronous speed repeaters not lined up with self-synchronous repeater in master speed repeater. 13. Check repeaters for electrical zero. Reset pointer or shift repeater frame to make speed readings agree.
14. Master speed repeater rotates in wrong direction. 14. Roller has slipped over 180-degree mark (point) of heart-shaped cam causing reverse operation of follow-up motor. 14. Deenergize 1Y circuit. Turn transmitter dial by hand until its reading agrees with master speed repeater pointer. Energize 1Y circuit, and gradually allow transmitter dial to assume its proper position.


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