Guidelines for Maintaining Stromberg Minute Impulse Clocks

Your Stromberg minute impulse wound master clock carries a heritage of timekeeping and time recording dating back to the early 1900s. Strombergs were developed to act not just as timekeeping devices, but to drive time-recording devices such as time stamps and time clocks. Today, we use them primarily as beautiful, very accurate clocks that remind us of an era of Industrial America like none other in history.

Tips on setting up and regulating your Stromberg

Make sure the clock is hung plumb and level. Use a level to make sure the wall is vertical. If not the pendulum may rub against the back wall of the case. You can check to see if the clock is level by the position of the pendulum on the beat scale when it is still. It should be in the center of the scale.

The Model 1900W-UNV winds EXACTLY every minute. Therefore the winding action can be used as a metronome to time the clock. For example, if you release the button on the top of the 1900W-UNV at exactly 00 seconds, every minute at exactly that same point the clock will wind. In 24 hours, you can look at it again and see if the clock is ahead of 00 (running too fast) or behind 00 (running too slow). Adjust the pendulum accordingly. To make faster, turn rating nut clockwise (front of nut to the right). To make slower, turn rating nut counterclockwise (front of nut to the left).

The Model 1900W-UNV

The Model 1900W-UNV acts as the heartbeat of the Stromberg movement. It provides the appropriate voltage signal, at the right time, to wind the clock reliably and safely. It is an innovative electronic device which converts the voltage from D cells to the properly conditioned and timed signal to power the winding coils of the Stromberg movement. As a result:

1. The clock does not have to be connected to an external power supply, so it can be located anywhere (not slaved to the location of your outlets in the room)
2. It does not require the internal contacts set of the clock even be present, therefore eliminating the chance that contact oxidation or wear out problems will stop the clock. Considering that the clock must reliably wind 525,600 times per year, this is pretty significant.
3. Battery change can be done for about $4.

Batteries on the Model 1900W-UNV will need to be changed about every 9 months. The clock will stop when the batteries are no longer strong enough to drive the clock.

After the clock has stopped, it will be necessary to manually wind it. This is easy to do. Simply depress and release the button on the Model 1900W-UNV about 20 times. The clock will wind with each button release. Wait until each winding is complete, and press again, until about 20 wind cycles have been heard.

Strombergs are generally very reliable. However, infrequently the heavy electromagnets will stick to the winding lever. This is difficult to explain, since the electromagnets are equipped with antimagnetic rings to prevent sticking. Nonetheless, it does happen albeit very infrequently. To release this condition, reach up and pull the winding lever to the right. Sometimes it helps at this point to reverse the brown leads (connected to the small terminals) on the 1900W-UNV.  This will have a tendency to demagnetize the electromagnetic yokes.

Setting Hands

The hands can be turned clockwise or counterclockwise on most Strombergs, although turning in reverse could tend to loosen the minute hand nut.  The hour and second hands should never be turned. In fact turning the second hand can do serious damage to the escape wheel resulting in a visit to Ken’s Clock Clinic.

In Case of Difficulty

If the movement refuses to run, it can be serviced by us and in fact is warranted for 2 years. We don’t need the entire clock, just the movement. It can be packed up and sent back via FedEx or UPS very economically. The movement can be accessed as follows:

1. Remove hands and dial. The dial is held on with 4 screws. Don’t lose these; they are 4-36 thread which is not a common hardware store size. Replacements have to be supplied by us.
2. Remove the two wires going to the movement.
3. Loosen three pillar screws in movement. These are recessed, captive pillars that reach down into the base of the movement and hold the movement in place. DO NOT REMOVE THE BASE FROM THE CLOCK CASE.

It is best to include the Model 1900W-UNV kit to rule out any issues with it.

Regular Maintenance

Send the movement back to us every 3-4 years for periodic oiling and inspection. Send the Model 1900W-UNV back with it and we will check it out as well. The cost for oiling and full inspection is $70. This will even cover correction of minor problems, should we encounter them, and a battery change. It’s best to correct minor problems while they are still minor.

This movement is simply not something that anyone without a background in Strombergs should attempt to adjust or repair; it is almost guaranteed to stump even the best mechanical clock repair folks. There are very subtle things that can be put out of adjustment very easily and other things that can be damaged permanently. We can give countless examples seen in the past. Also, do not try to oil the movement yourself. Just as important as knowing what to oil is knowing what NOT to oil, how not to oil it, and what oil to use.