The Junghans mystery style clock was first patented in 1909 and was popular from 1910 to 1930. The clock section itself is a standard piece, but the statue came in several designs - Diana, kangaroo, elephant, boy with bat and onion boy.
Servicing these clocks has sometimes been allocated to the too-hard-box because of one problem or another. Servicing the movement itself is straightforward, with attention given to the elimination of any wear in the train so that a good power supply is delivered to the escapement. The counterweight pendulum must rock from side to side smoothly to ensure proper running and a good action.
The jewelled bar needs to be checked for cracked or pitted jewels. The older bars need to be replaced if damaged. The modern bars have friction-fit jewels, which can be replaced. The minor problem with the friction-fit jewels is that if the statue is put down hard with the timepiece in position, the jewels can move letting the cross bar(with the steel pivots) hit the jewelled bar. If the jewelled bar needs to be replaced, the new bar's thread does not always fit the old block.
If the thread is broken in the block and cannot be removed then the block needs to be replaced. The block can be removed BUT caution must be used when doing this. Heat the block with a soldering iron only, no flames. Pay close attention to the solder around the block, when it starts to melt pull the block straight out with pliers.
Do not touch the hand of the statue with the soldering iron, this will disfigure the statue. Make a new block the same outside dimensions as the old block but with a new thread to fit the new bar. Coat the block with a film of solder and flux, screw the new jewel bar into the block for easy handling, heat the block and insert the block into the hole in the arm. Check the bar for level and square to the statue. Cut the thread of the new bar and secure it into the block. Most new bars have a small nut with it, this is used to lock the bar into the block.
The pivots can be removed so they can be polished in the lathe to a fine point to reduce friction. Rounded pivots increase friction and reduce the action. When the pivots are refitted they must be returned to their original position (depth). If not it will affect the regulation severely. Check that the bars are parallel and they clear each other.
The 'in-beat' of the clock is adjusted by slightly bending the centre bar of the gridiron section of the clock at the bottom above the ball. If the gridiron is too bent, then the pallets should be checked to see if they have been moved previously. The pallets should be moved as a last resort only.
The beat count for the movement is 5760 B.P.H. so it can be regulated on the clock rate machine, winding the pendulum up to slow the clock down and vice versa. A small adjustment (1/4 turn) changes the rate by approx. 1 min/day. When regulating, after setting the clock in beat, check that the centre rod of the gridiron does not rotate while adjusting as this will disturb the in-beat adjustment. There should be two screws holding the rod firm.
Broken statue hands can be repaired by pinning the two broken pieces together and soldering with a soldering iron only. Minimise the amount of solder being applied to reduce clean up and scratching the surrounding area. The join can be filed to a smooth finish and can be touched up with enamel paint, mixing the colours to achieve the correct colour.
The ribbon at the top of the clock should be present, as its absence will affect the clock's timekeeping. The glass if missing or broken should be replaced with the same style, crystal or plexi. If a plexi glass is fitted where a crystal was, and vice versa, then the timekeeping will be affected.
The timepiece case, if it has been painted or is tarnished, can be soaked in the clock cleaning solution to remove the paint and clean the gilding (depending on its condition). Most cases are only tarnished and have been painted instead of being cleaned. The case can then be lacquered to maintain the finish. The statue can be cleaned with soapy water and a toothbrush and dried with a towel.