CE 3120/3123 series

Failures of these clocks as used in Humber Snipes, Hawks, Alpines and maybe Hillmans are many and causes are varied.  Refer to Fig. 6 (exploded parts view) below.

Main cause is the carbonising of the offset pin on the balance wheel (48) and the corresponding contact pin (14) that sits on a fulcrum post.

Second cause is incorrect polarity applied when installing causing the rectifier bridge (17) and other items to be burnt out, rendering the clock inoperative.  White rectifier assembly (17) is negative ground where Green rectifier assembly (17) is positive earth.

Third is that any loose posts (15/10 & 19/21) within the clock itself will cause shorting to ground and cause carbonising in other areas.  Balance wheel hairspring (48) is one.

Fourth is when the earthing pin (16) to start the clock is used too often and particularly if any loose posts (15 & 10) are prevalent will cause secondary burning or carbonising throughout the clock mechanism.

Minor adjustments to the circuit can circumvent a lot of these problems.

One is to install a separate switch to disable the clock when not in use or when standing for long periods.  The second is to fit a small power diode (EM401) across the rectifier assembly (17) protecting it and the clock from spurious voltage sparks that causes carbonising.  Lastly a suitable capacitor 10uf 25V also fitted to ground from the rectifier assembly will reduce sparking and noise if a radio is fitted.

It is prudent to have the offset balance wheel cleaned every couple of years to stop carbonising, where possible.

Or one could fit a Kienzle or other quartz movement into the housing.  I believe some Rover clocks are also compatible.

 Front Reset Clock – General Arrangement of Movement:

1.Back Plate 2.Pole Piece Securing Screw 3.Setting Support Plate 4.Pole Piece 5.Spacer 6.Coil 7.Balance Support Nut 8.Balance Support Assembly 9.Centre Spindle and Wheel Assembly 10.Connecting Bracket 11.Rectifier Screw 12.Insulating Sleeve 13.Setting Spindle Return Spring 14.Contact Hairspring Assembly 15.Contact Hairspring Pillar 16.Setting Spindle 17.Rectifier 18.Rectifier Bridge 19.Upper Insulating Plate 20.Screw (for contact hairspring pillar) 21.Lower Insulating Plate 22.Setting Pinion 23.Setting Spindle Washer 24.Setting Wheel 25.Setting Pinion Spring 26.Setting Spindle Collar 27.Minute Wheel 28.Insulating Tube 29.Rectifier Pillar 30.Retaining Plate 31.Retaining Plate Screw 32.Dial Washer 33.Regulation disc 34.Hour Wheel 35.Spring (for regulaton disc) 36.Locating Plate Screw 37.Bottom Bearing Locating Plate & Adjustable Bearing 38.Cannon Pinion 39.Balance Platform Assembly 40.Friction Spring 41.Insulating Ring 42.Regulating Spindle 43.Double Support Plate 44.Double Support Plate Securing Screw 45.Transverse Wheel Assembly 46.Escape Wheel Assembly 47.Balance Wheel Assembly 48.Regulator Disc Spindle Assembly 49.Anchor Post 50.Anchor Post Screw 51.Hairspring Taper Pin 52.Top Bearing Assembly 53.Regulator Lever Assembly 54.Regulator Lever Washer 55.Top Bearing Screw 56.Regulator Wheel 57.Setting Spindle Washer (Brass)

The Balance Wheel :

IMPULSE PIN-CONTACT SPRING – ALIGNMENT:                 The balance wheel should now rest as shown in the illustration below. If this is not the case, steady the balance wheel, insert the into-beat tool SR/D.10 into the slot in the hairspring collet and adjust the hairspring tension until the correct position is obtained. IT IS IMPORTANT THAT THE IMPULSE PIN DOES NOT TOUCH THE CONTACT ARM.   The bottom bearing if relieved, can now be screwed in until there is just sufficient enshake in the balance to ensure free running. The reset wheel should now be fitted using a hollow punch or a similar suitable tool.

CIRCUIT DIAGRAM:

TECHNICAL DESCRIPTION:                         Current flows from the supply terminal to the wiper contact via the rectifier, rectifier bridge, contact hairspring and the coil which is connected in parallel with the rectifier. The earth return for completing the circuit occurs through the hairspring when the wiper contact touches the impulse pin.   When the starting spring is brought into contact with the rectifier bridge it completes the circuit and energises the pole pieces causing the balance wheel to deflect.   When the spring is released current ceases to flow in the coil allowing the hairspring to return the balance.   The wiper contact and impulse pin now take over the function of supplying the current pulses to the coil as the balance oscillates.