Multi-Split Chronometer
© copyright 1992 Timewise
Printed with permission of Timewise

Table of Contents


for choosing the TIMEWISE 610 Multi-Split Chronometer! Your TIMEWISE 610 is an accurate and versatile multiple split checkpoint clock that will give years of dependable service. If you've used traditional rally checkpoint clocks, you'll really appreciate the improved quality, mistake proof operation, and simplified time setting procedures provided by the TIMEWISE 610.

How to Use This Manual

For a brief description of what the 610 does, read the Introduction.

The section covering the Operation of the 610 will teach you how to use the instrument. Clock setting procedures, the master/slave autosetting procedure, the remote split input connection and features, as well as battery conserving techniques are described there.

Please read the Maintenance & Troubleshooting section. Some "do's" and "don't's" on the care and feeding of the 610 are discussed there.

TIMEWISE 610 Features


The TIMEWISE 610 is designed with reliability and ease of use in mind. A multi- position rotary switch is used to set the clock and change operating modes. To prevent accidental loss of time, a simple, but secure, clock setting procedure is used. There is no ON-OFF switch that can be accidentally thrown. Snap-action pushbutton switches provide tactile feedback, while an audible alarm signals when a split has been entered. Placing the pushbutton switches on the left side frees the right hand to record data.

The use of large scale integrated CMOS technology keeps component count and power dissipation to a minimum, while simultaneously providing increased reliability. The 610 uses a microcomputer designed for applications where ultra-low power consumption and a wide operating voltage play a significant role in product specification and selection.

What the 610 Does

The TIMEWISE 610 checkpoint clock provides control workers an accurate and easy to read digital time of day clock. The time of day is shown on a 6 digit, 0.5" tall character, extended temperature range, high humidity tolerant LCD that assures easy readability, even in bright light. A quartz crystal oscillator accurately maintains the time to within one second over 72 hours.

In addition to keeping time, the 610 is used to "split" the current time as a rally car enters a checkpoint. Effectively, the clock is visually frozen, while continuing to count internally. The 610 can store up to ten split times in memory. Each split time can be recalled at the push of a button.

Time of day is displayed in the standard six digit format of hours, minutes, and seconds (12:59:59). Alternatively, the 610 can display hours, minutes, and hundredths of a minute (12:59.99). The clock can be set to any hour, minute, or second (hundredths of a minute). You can adjust the clock at any time ... even by one second ... up or down! You can switch between counting in seconds or hundredths of minutes at any time; and, you can synchronize the beat of the clock to a time standard at any time. As an option, the 610 can also show time resolved to tenths of a second (59:59.9).

One TIMEWISE 610 can automatically set the time in another 610 simply by interconnecting a common stereo audio cable. This will synchronize the clock on a slave unit to within one thousandths of a second to a master 610. This master/slave clock setting procedure can take place at any time.

Finally, for nighttime use, the display can be momentarily backlit with an internal light source. An optional 6 volt input for continuous backlighting is available.


There is no ON-OFF switch for the TIMEWISE 610. If the time is not visible in the display, depress either the SPLIT or RECALL pushbutton switch. This will bring the clock out of its battery saving, power down mode.

If the 6 10 has been powered down for more than 24 hours, the clock will need to be set again, otherwise the time will still be correct. In such a case, you may begin using the 610 immediately.

Splitting the Clock

When the SPLIT switch is depressed, the time of day is visually frozen. You may split the clock while the rotary switch is in any position. If RUN was selected on the rotary switch, the buzzer will briefly sound. (The 610 is split at the exact moment you depress SPLIT; however, the buzzer may be delayed slightly because of some internal housekeeping.)

While split, the 610 continues to keep track of the passage of time. When you depress RECALL, the clock will once again display the current time. It will be as if you had never entered the split mode at all.

If you depress SPLIT, again, before recalling the live clock, the 610 will save the new split time internally. Depressing RECALL will call up that new split time. Depressing RECALL a second time will being back the live clock.

You may depress SPLIT up to ten times before its memory fills up. Each activation of RECALL will then display the split times in the order they were saved. After all split times have been recalled, the clock will become live again.

Note that when the 610 is split, a decimal point is visible between the hours and minutes. (This is in addition to the colon normally present there.) When ten split times have been entered into memory, two additional radix indicators will be visible in the display, indicating that the split memory is full.

Setting the Clock

Notice the "up" and "down" arrows next to the SPLIT and RECALL switches. These arrows signify that, when setting the clock, the pushbutton switches will change the clock's value up or down. The "up arrow" pushbutton increases a selected unit; the "down arrow" pushbutton decreases a selected unit. (Holding a pushbutton down changes the selected unit repeatedly.)

To set the clock in the TIMEWISE 610, start by turning the rotary switch to RUN. Then, at a noted time of day, depress and hold the SPLIT switch down. While continuing to depress SPLIT, turn the rotary switch to one of the clock setting positions: SELECT MODE, SET SEC, SET MIN, or SET HOUR. Now release the SPLIT switch.

Then, using the "up arrow" and "down arrow" switches, adjust the clock to the time of day at which you initially depressed the SPLIT switch. You can select among the SET SEC, SET MIN, and SET HOUR positions as needed.

After setting die clock, turn the rotary switch to RUN to exit the clock setting mode.

To repeat, here's the step by step method for setting the clock:

  1. Turn the rotary switch to RUN.
  2. Noting the time of day, depress (and hold) SPLIT.
  3. Turn the rotary switch to SELECT MODE, SET SEC, SET MIN, or SET HOUR.
  4. Release the SPLIT switch.
  5. Use the "up arrow" and "down arrow" switches to adjust the clock to the time noted in step 2. You can select among the SET SEC, SET MIN, and SET HOUR positions as much as necessary.
  6. Turn the rotary switch to RUN.

The current time of day will now be displayed. If your reaction time was a bit slow when initially depressing the SPLIT switch, you may find the clock to be off by one second. If so, repeat the above procedure and adjust the clock one count.

Note: You may take as much time as you wish to set the clock. This is because the 610 adjusts the internal "live" clock by the same amount that you adjust the displayed split clock. When you exit the clock setting mode, the live clock will have been adjusted by the correct amount, regardless of how long you spent executing the procedure.

Synchronizing the Clock

Setting the clock does not alter the beat of the clock. That is, the "ticking" pulse of the clock is not changed. If the beat of the clock is "out of sync" with the official time standard, you should also synchronize the 610 to the time standard.

To do so, enter the clock setting procedure again, this time selecting the SYNCHRONIZE rotary switch position. When you select this clock setting function, the clock will temporarily become "live" again. Now use the "up arrow" and "down arrow" switches to make the clock run slightly fast ("up arrow") or slow ("down arrow"). When the clock is beating in synchronism with the time standard, release the pushbutton. Repeat if necessary.

After you are satisfied that the clock is synchronized to the time standard, turn the rotary switch to one of the other clock setting positions (SELECT MODE, SET SEC, SET MIN, or SET HOUR). Note that at the moment you de-select the SYNCHRONIZE position, the clock is once again split. If necessary, correct the new split time. (While synchronizing, you may have sped the clock up or slowed it down by a full count.)

Changing the Counting Mode

The clock may be run in either hours, minutes, and seconds (11:59:59) or hours, minutes, and hundredths of minutes (11:59.99 - notice the decimal point instead of a colon following the minutes.)

To change between "seconds" and "hundredths of minutes", enter the clock setting mode as describe above, choosing SELECT MODE on the rotary switch. Then, depress either the "up arrow" or "down arrow" to toggle between the two counting modes. With each push, the 610 will change its counting mode. You may alternate between the two modes as often as you wish.

One advantage to being able to change the counting mode of the clock is evident when setting the clock at the beginning of the rally. You can use the "seconds" mode while aligning to WWV or another broadcasted time standard; then switch to "hundredths" to run the rally.

Note: Although the counting mode of the clock may be changed at any time, stored split times are erased when entering the clock set mode. You cannot collect several split times while in "seconds" and read them back in "hundredths."

Automatic Master/Slave Synchronizing

One TIMEWISE 610 can automatically set the time in another 610 in a master/slave arrangement. That is, a 610, previously aligned to the official time, can insert that time into another 610. This synchronizing operation takes about two seconds and may be performed at any time.

To execute the automatic synchronizing procedure, you will need an interconnecting synchronizing cable. A standard stereo audio cable is used for this purpose. Such a cable is readily available from Radio Shack as part number 42-2387. This 6-foot stereo audio cable (two wire plus shield) has the required 1/8" stereo miniature phone plugs at each end. (You may, of course, fashion your own cable using 1/8" stereo plugs and three wire cable. To do so, just connect the three contacts of the plugs straight through. Keep the cable shorter than 7 ft.)

To synchronize two 610s, turn the rotary switch on the master 610 (the unit with the official time) to RUN, and the rotary switch on the slave to SYNCHRONIZE. Then plug the synchronizing cable into each unit's REMOTE SPLIT input jack. Finally, depress RECALL on the slave. The display on the slave will go blank for a moment. When the display comes back on, the slave 610 will be set to the exact time as the master 610. The counting mode of the master 610 ("seconds" or "hundredths of minutes") will also be set in the slave 610.

Note: As you insert the synchronizing cable into each unit's REMOTE SPLIT input, the contacts in the cable may temporarily short together causing either or both 610s to split the time. This will not interfere with the synchronizing procedure. You can, if you wish, "unsplit" the master before synchronizing. Removing the cable also usually splits the 610s.

Take care not to shuffle the master and slave ... you don't want to set the time in the master to that of the slave!

The Remote Split Input

The REMOTE SPLIT input provides a means of splitting the TIMEWISE 610 via an external switch closure.

To activate the REMOTE SPLIT function, all you need to do is make an electrical connection between two contacts in the input jack. Do not apply any voltage to any of the contacts!

To use the REMOTE SPLIT input, you must build a plug/cable/switch assembly. Here's what you need (Radio Shack is a good source for all these items):

  1. Miniature stereo phone plug (three contact; 1/8th inch diameter).
  2. Two conductor cable (shielded cable is recommended but not required).
  3. A single pole, normally open switch.
  4. The correct tools and materials for cutting, stripping, and soldering wires to the switch and plug.

The cable assembly is easy to make: At one end of the cable, solder one conductor each to the "ring" and "shaft" contacts of the miniature phone plug. (The ring is the middle contact visible on the plug; the shaft is the contact nearest the handle.) At the other end of the cable, solder one conductor each to the switch contacts. With shielded cable, solder the shield drain wire to the shaft contact on the plug. (Note: The "tip" contact of the REMOTE SPLIT input plug is the data pathway for the automatic synchronizing procedure. Don't connect the external remote switch to that contact.)

Once assembled, plug the cable into the REMOTE SPLIT input on tile 610. Each time the switch contacts close, the 610 will be split. You may also split the 610 manually while using the REMOTE SPLIT input.

CAUTION! Avoid discharging static electricity into the REMOTE SPLIT input. A static discharge into the input can damage the 610!

Remote Input Specifications

Contact descriptions for the connector are:

Shaft - Ground; connected to negative side of the 6 volt battery supply.
Ring - Remote split input; held high (to 5.3 volts) with a 1OK ohm pull- up resistor and connected to a CMOS input via a 1K ohm series resistor. The input must be brought to 0.5 volt or less for a split to be sensed and returned to 5 volts to reset the circuitry. After receiving a remote split, the 610 waits at least 0.6 second before another split can be sensed.
Tip - Synchronization data in/out; held high (to 5.3 volts) with a 330K ohm pull-up resistor and connected to a CMOS gate via a 1K ohm series resistor. Synchronization data is continuously transmitted when RUN is selected; data is accepted when SYNCHRONIZE is selected and RECALL is depressed.

Lighting the Display

In low ambient light levels, the display on the 610 may be temporarily illuminated by depressing the small pushbutton located between the SPLIT and RECALL switches. The LCD backlighting will remain on as long as you depress the pushbutton.

As an option, the 610 can have a 6 volt DC input jack installed that will allow continuous LCD backlighting. If you have this option, there will be a small coaxial power receptacle (5.0mm OD, 2.1mm ID; + on center pin, - on sleeve) accessible on the right side of the instrument.

A 6 volt DC source is readily available from Radio Shack. Their part number 270-1562 is a universal DC-to-DC voltage regulator/adapter that plugs into a vehicle cigarette lighter socket. This power adapter comes with a selection of interchangeable coaxial plugs, one of which fits the receptacle on the 610. Select the 6 volt output setting on the regulator.

Important: The optional continuous backlighting connection is for 6 volt DC power. Although it is possible to brighten the display backlighting by applying more than 6 volts to this input, higher voltages cause the 610 to heat-up. Generally, up to 9 volts can safely be applied before the unit overheats. However, do not apply 12 volts to the backlighting input ... permanent damage will eventually occur!!

Conserving Batteries

The TIMEWISE 610 will automatically turn off its display if neither the SPLIT nor the RECALL switch are depressed for six hours. After the display blanks, depress either pushbutton and the clock will once again be visible, with the time being correct. However, if neither switch is depressed for 24 hours, the 610 shuts down completely. The time of day clock will then have to be reset.

You can speed up the complete shut down of the 610, if you wish, by turning the rotary switch to the unlabeled position immediately clockwise from the SYNCHRONIZE position, and then depress RECALL (while the clock is live). This makes the 610 immediately blank the display and completely shut down in only six hours. Depressing SPLIT (or RECALL after selecting another rotary switch position) returns you to the normal running mode.

NOTE: By leaving the rotary switch in the blank position immediately clockwise from the SYNCHRONIZE position, the 610 consumes about 15 milliamps less current. This can effectively extend the battery life an additional 3 to 4 months during storage.

NOTE: Also note that for each second the LCD backlighting is used, the batteries are drained the equivalent of one hour of normal operation. If you use the backlighting often, the batteries will have to be replaced more than once per year. If you cannot see the LCD backlighting in the dark, it is time to replace the batteries. (The 610 will run about one month on batteries that no longer activate the LCD backlighting.)


Replacing Batteries

The batteries in the TIMEWISE 610 must be changed once each year. Use four fresh "AA" alkaline batteries. The batteries are accessible by opening the 610. To do so, remove the phillips head screws in the four corners. The case can then be pulled off, revealing the battery holder.

The battery holder indicates the correct orientation for the batteries. Check the battery holder contacts for signs of corrosion and carefully clean as required. When re-installing the four phillips head screws, take care not to cross-thread them in the case ... and don't overtighten them!

Electrical Troubleshooting

If you experience problems with the TIMEWISE 610, here are several areas to investigate before concluding that the instrument is broken.


The TIMEWISE 610 uses industrial grade components throughout its construction and is designed to operate in the broad temperature range generally experienced within a vehicle. Still, on hot summer days with little wind blowing, the temperatures reached in a parked closed vehicle can exceed 165 degrees F. In that environment, the LCD will exceed its maximum operating temperature and may be permanently damaged.

Therefore, please keep the 610 out of direct sunlight while stored in the still air of a closed vehicle during lunch breaks, rest stops, or whenever you leave your vehicle for substantial lengths of time. Also, don't store the instrument in the glovebox.

Cleaning the 610

Be careful when cleaning the front panel. Abrasive grit and certain cleaning chemicals can mar the panel. Use a soft cloth with a mild plastic cleaning solution or a weak solution of dishwashing liquid and water. Do not use chemical solvents, ammonia glass cleaners, bathroom and kitchen cleansers, or aromatic hydrocarbon based cleaners. Wipe accumulated dirt off carefully to prevent scratches.

Never spray a cleaner directly on the 610; rather, spray a cloth and then clean the panel with the damp cloth. If you spray a cleaner directly on the front panel, some of the liquid will enter the switches and cause internal corrosion and eventual failure of the mechanism.

WARNING! Chemicals used in insect repellents will damage the front panel on the 610.

Oscillator Adustment

The TIMEWISE 610 uses a quartz crystal oscillator to accurately maintain the time. The frequency of this oscillator has been adjusted to provide a clock accurate to within plus/minus one second after 72 hours.

After a period of time, the crystal and other parts of the circuit age and the frequency of the oscillator drifts slightly. (This is true for all oscillator circuits.) The clock will then gain or lose time to a greater amount than the specified accuracy. The oscillator frequency should then be re-adjusted. Although the procedure is simple, the equipment required to make the frequency adjustment is quite specialized. TIMEWISE will calibrate any 610 for a minimal charge.

Do not adjust the oscillator unless you have the appropriate test equipment.

Here's the oscillator calibration procedure:

  1. Open the 610 and remove one of the batteries from the battery holder. This will remove all power from the instrument.
  2. While depressing SPLIT, re-insert the battery. Wait one second and then release SPLIT. The 610 will enter a special oscillator adjustment routine (the clock will not count), sending a 1280 Hz square wave signal to the tip contact of the REMOTE SPLIT jack. Connect this signal to a frequency counter.
  3. Locate a small adjustable capacitor on the back side of the printed circuit board. On most 610s this capacitor is actually mounted on the front side of the printed circuit board, but is accessed via a hole in the board. Carefully insert a small non-conductive flat-blade adjustment tool into the capacitor.
  4. Adjust the output signal to 1,280.000 Hz plus/minus 1 mHz. The adjustable capacitor will need to be turned very little. (As a matter of interest, the clock will be accurate to plus/minus 1 second after 72 hours if the oscillator is set to 1,280.000 Hz plus/minus 5 mHz.)
  5. After making the adjustment, remove and re-insert the battery, without depressing SPLIT. Normal operation resumes.

A Comment About Static Electricity

Do not open the TIMEWISE 610 except to replace the batteries. Some components within the instrument are very sensitive to static electricity. A static discharge to a solder trace on the printed circuit board can damage the instrument. You can damage the 610 with a static charge that is a thousand times weaker than the energy required to form a spark.

Don't fool yourself about your immunity to static electricity. While driving, a static charge is generated within the entire vehicle as the tires flex against the road. Such static charges are generally dissipated evenly throughout the vehicle and therefore do not cause a problem. However, fabric used to cover seats can lead to a localized charge on your body. In such a case, touching the metal knurled nut on the REMOTE SPLIT input or a cable connected to that input can cause a problem.

If you've experienced a problem with static electricity in your vehicle, TIMEWISE suggests you treat the inside of your vehicle with a static dissipating chemical. Anti-static treatments, often in an aerosol or pump spray bottle, are available from stationary and computer stores.


Design CPU type:

Operating memory:

Multi-split storage:
MC1468705F2 @ 40.96 KHz or
MC1468705G2 @ 153.6 KHz
Program: 1079 bytes Data: 64 bytes
Extended temperature range, high humidity
tolerant, 0.5" tall character, 6 digit LCD
10 memories (first in - first out)
12:00.00 to 11:59.99 (:59)
Optionally: 00:00.0 to 59:59.9 (minutes:seconds.tenths)
Clock Accuracy Plus/minus 0.01 minute after 72 hours
Electrical Power source:
Power requirements:

Expected battery life:
4 "AA" alkaline batteries
4 to 6 VDC; 80 milliamps typ. (85 mamps when
LCD backlight activated)
9,000 hours (greater than 1 year) during normal use. (Battery life is significantly decreased when the LCD backlighting is used. Activating the backlighting for 5 seconds consumes the same energy used during 5 hours of normal operation.)
Optional external power requirements for continuous LCD backlighting: 6 VDC; 100 mamps or 9 VDC; 130 mamps
Environmental Storage temperature:
Operating temperature:
-40C to 90C
-25C to 70C
90%, non-condensing
Physical Enclosure:
Front panel:
Optional DC input jack for continuous backlighting:
Scratch protected polycarbonate over aluminum
4.025" x 2.925" x 2.3" (including height of switches)
Approximately 11.5 oz. (including batteries)
5.5mm OD, 2.1mm ID; (+ on pin, - on sleeve)


Limitation on Warranty and Liability

TIMEWISE warrants this equipment to be free from defects in material and workmanship for a period of two years from the date of shipment to the original purchaser. This warranty is limited to the repair and replacement of parts and the necessary labor and services required to repair the equipment. This warranty is made in lieu of all other expressed or implied warranties, whether written or oral.

Except as specified below, this warranty covers all defects in materials and workmanship. The following are not covered: Damage as a result of accident, misuse, abuse, or as a result of installation, operation, modification, or service on the equipment; damage resulting from failure to follow instructions contained in the User's Manual; damage resulting from the performance of repairs by someone not authorized by TIMEWISE; damage caused by exposure to liquids, solvents, salty air, or corrosive gases; damage caused by exposure to excessive amounts of dust or dirt; damage caused by exposure to temperatures above or below the storage or operating limits of the equipment; or normal wear of the instrument enclosure, connectors, or cables.

While under warranty, TIMEWISE will service, repair, replace, or adjust any detective part or parts free of charge, when the instrument is returned freight prepaid to TIMEWISE. The purchaser is responsible for insuring any equipment returned, and assumes the risk of loss during shipment.

Limitation of Implied Warranties and Exclusion of Certain Damages

All implied warranties, including warranties of merchantability and fitness for a particular purpose, are limited in duration to the length of this warranty.

In no event will TIMEWISE be liable to the purchaser or any user for any damages, including incidental or consequential damages, expenses, lost profits, lost savings, or other damages arising out of the use or inability to use this equipment. This exclusion includes damages that result from any defect in the firmware or manual.

How to Obtain Repair Service

If your TIMEWISE equipment requires service, return it to TIMEWISE directly. Do not return it to your dealer. Include a detailed description of the problem. TIMEWISE must be able to verify the problem in order to repair it. Please include telephone numbers at which you can be reached during the day and evening.

Equipment to be repaired must be returned freight prepaid to TIMEWISE. All equipment must be packaged with sufficient protection against shipping damage. You are responsible for transportation charges when returning equipment to TIMEWISE. Insuring the shipment is recommended. Warranty repairs will be returned via UPS ground freight prepaid. Non-warranty repairs will be returned via UPS ground COD (repair charges, freight, and COD collection fee), cash only, unless prior arrangements have been made. Alternate shipping methods can, or will, be used as necessary to assure a prompt and safe delivery.

Repairs on equipment out of warranty or when abnormal usage has occurred will be charged at applicable rates. Upon request, TIMEWISE will submit an estimate for such charges before commencing repair.

About this Manual and the Operating Firmware of TIMEWISE Equipment

The layout of this manual and the operating procedures for TIMEWISE equipment are trademarks of TIMEWISE. No part of this manual or the operating firmware for TIMEWISE equipment may be copied or reproduced, in whole or in part, without written consent from TIMEWISE. The duplication, disassembly or dumping of operating firmware is expressly prohibited.


Although every effort has been made to make this User's Manual technically accurate, TIMEWISE assumes no responsibility for any errors, omissions, inconsistencies, or misprints within this document.

For Further Information

Please feel free to contact TIMEWISE should you have any comments about this equipment. We encourage suggestions for product improvements. Special applications or customization of TIMEWISE equipment to individual needs will also be entertained.


As of December 1992, the TIMEWISE 610 Multi-Split Chronometer can store up to 21 split times before its memory is full. (Previously, a maximum of ten splits could be stored.) Note, too, that when the memory is full, all radix points turn on ( . . . . . ) instead of just the three leftmost ( . . . ).

Also, the 610 can now show tenths of seconds or thousandths of minutes. To do so, turn the rotary switch to its "10 o'clock" position. (This is the position immediately clockwise from RUN.) The time shown will be tenths of seconds (59:59.1) if you use the seconds counting mode of the clock; the time will be thousandths of minutes (59.999) when using the "hundredths" mode. The buzzer will also sound when you split while in the "10 o'clock" position.

1119 Midway Road
Northbrook, Illinois 60062 USA
(847) 550-5052
Users Manual 1001-610 Rev 2
Printed January 1992

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