1 Overview
The U600 / U60* caliber is a complex watch and it’s difficult to remember how to navigate its core functions of selecting the time modes and setting them. The manual is fairly complete, but badly structured and ridiculously complex. This is an attempt to explain things in a structured and easier to remember way. It took a whole day to write!
1.1 Core Functions and Basic Operation
There are two time zones that can be kept: Home and World. Home is per definition the time shown on the left LCD (which is also on the main dial) and the World time is per definition the time shown on the right LCD. The third time is UTC which has a dedicated hand, and to which all zones are related to by a fixed delta.
Operation of the watch is generally based on the Home time zone (left LCD). Any configuration changes are made operating on a World time zone (right LCD). Finally, these time zones can be swapped back and forth to enable full configuration of the whole.
Home should really have been named Primary and World should have been Secondary.
- Home Time Zone – on left LCD and main dial. Determines radio type used to set UTC.
- UTC reference time – set via radio, or manually.
- World Time Zone – on right LCD, a delta (relative difference) to UTC.
Major functions beyond indicating time are the following (see manual for details):
- Chronograph (CHR) up to 24h, 1/100s units
- Timer (TMR) 1…99min, 1min units
- Alarms (AL-1/2)
- Radio time signal reception (RX-S)
- Bezel as mechanical calculation tool
1.2 Controls
There are two buttons on the right, the lower button A, upper button B. Here we also call the crown a rotational button C.
| Button | Function in general |
| A (lower) | display last radio sync (C0, TME, CAL, or RX-S mode) hold till beep for initiation of radio sync (C0, RX-S mode) down scroll selection or tuning (C1, C2) |
| B (upper) | LCD backlight for 2s (C0) up scroll selection or tuning (C1, C2) |
| C (crown) | rotation for up/down selection or setting (C1, C2) |
The crown can be pulled out in two positions: 1 and then to 2, and rotated.
| Position | Function in general |
| 0 | Regular operation: Crown rotation – no effect, buttons: LED light, start/stop timers, etc. |
| 1 | MODE select position. Crown rotation to select MODE |
| 2 | Correction position. B to select property, A to change, C rotation to tune |
Notation adopted in this post: A, B, A+B, indicate push and release of a button or both buttons, Cx indicates moving the crown to position x, and { } indicates a selection action by rotating the crown.
1.3 Modes
The modes determine both the function of displays and the information displayed or provide access to different functionalities beyond showing time.
| MODE | Purpose |
| TME – typically active mode | Time display and setting |
| CAL – typically active mode | Calendar display and setting |
| TMR | Countdown timer |
| CHR | Chronograph also: zeroing positions of hands (EUR, 12noon, 0 all hands) also: factory reset |
| WT-S | Time zone list settings |
| AL-1/2 | Alarm 1/2 |
| RX-S | Radio time and DST synchronization settings |
1.4 Display
There are 7 displays/indicator groups as listed in the Table below. See details on pages 6-8 of full manual.
| Indicator group | Functions |
| Time hands | Home (left LCD) time display seconds hand: 2s interval ticks means battery level warning seconds hand: radio signal reception level or syncing state |
| Mode hand (bottom) | function MODE |
| LCD Display left (#2) | HOME time zone city, shown by main hands RX mark for initiated radio reception process (M) to indicate crown being in position 1 (C1) |
| LCD Display right (#1) | WORLD time zone city insufficient charge warning mark time and AM or PM timer time timer measurement mark alarm mark SMR mark for daylight saving time |
| Batt. hand (top left) | battery condition or radio signal type |
| UTC hands (top) | UTC time display |
| 24h hand (top right) | 24 hour, linked to time hands |
If you are not certain about the state of the watch, make sure the watch is charged sufficiently, and confirm the zeroing of the indicator hands. Perhaps start with a factory reset to start with a clean slate. Each of the 44 time zones could have a non-default wrong setting. Refer to Other Topics section below for that, then return here.
2 Configuration
Generally, to make a change, first select a MODE using crown in C1 position and rotating it, then make a change with A, B, and/or crown in C2 position.
There are 4 MODES involved in setting time: TME (time), DTE (date), WT-S (list of time zone settings) and RX-S (radio reception)
2.1 Configuring of Time and Date
Select WORLD TIME Zone City (LCD right)
C1{TME} – A/B{scroll up/down city} to select a time zone city.
City “HOM” is a custom city for which the user can set a UTC time difference manually. Cities can be hidden from the selection list, and configured in detail, see WT-S
Swap LCD Left Time for LCD Right Time
C1{TME|CAL} – A+B to swap, confirmed by a beep after the A+B press.
The selected city/zone for the Main Hands is shown on LCD left after selection is completed, while selection is done on LCD right.
Set WORLD TIME (LCD Right)
C1{TME} – C2 to enter the settings of the shown time zone city. Use upper button B to cycle through the properties and A or crown to change them. (The crown operates the same as when zeroing hands.)
NOTE: The only setting actually changing that of the specific time zone, is DST. All other settings change all other time zones and UTC if applicable.
| Property | Button |
| Daylight Saving Time (DST) | A to choose On / OFf |
| Seconds (for ALL ZONES) | A to reset 00 |
| Minutes (for ALL ZONES) | C{rotate} to change |
| Hours (delta is applied to ALL ZONES, i.e. UTC) | C{rotate} to change |
| 12 vs 24 hour mode (for ALL ZONES) | A to choose |
Set WORLD Zone City Date (LCD Right)
C1{DTE} – C2 to enter the settings of the shown time zone city date. Use upper button B to cycle through the properties and C crown to change them. (The crown operates the same as when zeroing hands.) The day of the week is calculated automatically.
| Property | Button |
| Month (delta is applied to ALL ZONES, i.e. UTC) | C{rotate} to change |
| Day (delta is applied to ALL ZONES, i.e. UTC) | C{rotate} to change |
| Year (delta is applied to ALL ZONES, i.e. UTC) | C{rotate} to change |
Configure List of Time Zone Cities (LCD Right)
C1{WT-S} – C2 to configure time zone cities and/or user-defined HOM city.
| Property | Button |
| Daylight Saving Time (DST/SMT) (SAME as in TME/DTE setting) | A or C{rotate} to change: ON / OFf (default) * |
| Un-hide | A or C{rotate} to change: OFF / SET (default) |
| HOM only delta seting: Time=UTC-delta | C{rotate} to change: delta / –:– (default) |
HOM can be customized in 15-minute increments from UTC, -12…+14 hours.
*The manual implies that the radio signal, if enabled to (AUto), overrides and DST setting of a time zone set in WT-S, TME, or DTE modes. To avoid this override you must set the radio mode to MAnual. This is not the best implementation but it is what it is!
It is unclear if the radio signal changes the setting as shown in TME/DTE/WT-S, probably it does. In fact, the radio signal DST control impacts time zones in groups:
2.2 Radio Time and DST Signal Reception
Radio reception setting depends on the Home time (actually the home time difference relative to UTC) that is set: If home city is out of reach of the radio transmitter, this won’t work and time needs to be set or corrected manually. Be aware that radio based setting of DST may not be reliable, or even correct at all times.
If the Home time is UTC, radio does not work. If MODE is not TME, CAL or RX-S, radio does not work either.
Radio time reception is initiated and if needed re-tried automatically until successful daily based on the Home time zone on left LCD, on 2AM, 3AM, and 4AM. The 4AM time can be moved to a user-set time of day (manual 66-69). Radio setting can also be disabled entirely (p.66-69).
Radio time reception can also be initiated on-demand, see below.
Radio time reception that has started takes 2-15 minutes, but can be interrupted and cancelled using A{2s hold}
Configure Radio Reception of Time and/or DST
C1{RX-S} shows current setting: AUT means Automatic reception.
C1{RX-S} – C2 enters configuration editing mode, B selects property, and A or C{rotate} are used to set properties.
| Property | Button |
| Enable reception of Time signal | A and C{rotate} to set: AUT / MAN (time) / OFF |
| Enable reception of DST signal – SMT | A to set MA / AU (default) |
Time AUTo and DST AUto override any other settings. Time MAN sets a specific time instead of the 4AM time, but otherwise behaves the same as AUTo. OFF does not set time. DST MAnual disabled the setting of DST. It is unclear of Time OFF implies DST MAnual.
In addition, if a radio changes the DST of one city served in a group, the others; DST changes as well. The manual groups LON, PAR, ROM, BER, MAD, ATH, MOW and PDL, and groups ANC, LAX, YVR, DEB, CHI, MEX, NYC and YMQ. I suppose unlisted cities are not impacted but I am not sure!
| Objective | RX-S setting of SMT(DST) | TME/WT-S setting of SMT(DST) |
| Disable DST in a time zone city manually | MA (manual) – ignores radio DST signal | OF (off) |
| Enable DST in a time zone city manually | MA (manual) – ignores radio DST signal | ON |
| Enable radio setting of DST | AU (automatic) | overridden by radio when received |
Initiate on-demand Time setting
Because the antenna is on the left side of the watch, point 9th hour of the dial towards the radio transmitter (say Colorado in US), in front of a window facing that transmitter location.
C1{TME|CAL|RX-D} – C0 to prepare.
A{2s hold} to initiate, confirmed by beep and second hand pointing to RX. After sync completion, the hands will return to showing the set time.
Confirmation of Last Radio Reception Attempt
C1{CAL|TME|RX-D} – C0 to prepare.
A to make second hand show strength of signal H, M L or NO and batt hand show station JPN, EUR or USA, and left LCD shows SMT ON or OFF.
3 Other Topics
3.1 Calibrating Hand Reference Position
C1{CHR} – C2 move all hands to reference position.
WAIT until hands have stopped moving.
If not all at noon position, and batt. hand at EUR position, enter correction mode, or otherwise stop with C0:
B{2s} until CHA flashes on LCD left to enter correction mode for the first hand.
B changes the flashing indicator to calibrate the next hand in the table below. C2{tune position}. You can cycle through the hands continuously. Turning the crown two clicks in quick succession will make the hand run until a next click. Stop the hand and fine-tune using single clicks slowly. Set all hands to the listed target position:
| Flashing indicator | Hand | Target position by tuning |
| CHA | Batt. charge level hand | EUR (6 hour position, down) |
| UTC | UTC time hands | 12 noon, top |
| HR | hour hand | 12 noon top |
| MIN | minutes hand | 12 noon top |
Complete with B{2s} confirmed by (0) displayed in left LCD (#2), then C0
3.2 Factory Reset
C1{CHR} – C2 – A+B resets confirmed by triple beep
Home and local time set to UTC; time to 12AM, January 1, 2007, radio time setting to AUTomatic, DST disabled for all time zones, DST radio setting to AUtomatic, and zeroing of hands set to factory default. However, I had the experience that the zeroing of the hands did not reset.
3.3 Miscellaneous Behavior
Power saving function: Without exposure to light for 30 minutes, LCD display is disabled. After a week without exposure hands are stopped as well.
Hands move in sequence, not at once. To make changes to settings the user needs to wait till all movement has completed, with the exception of when the MODE is changed or crown changes position.
3.4 Some Key Specifications
- Without radio reception, monthly time deviation withing 15 s at room temperature.
- Acceptable temperature range 0 C to 50 C.
- Radio reception (determined by Home time zone, see p35 of manual for list):
- JPN is JJY Fukushima 40kHz and Kyushu 60kHz, Japan, East Asia: KHI…SUV
- USA is WWVB Colorado 60 kHz, North-Mid America, less Alaska, Hawaii: MID…RIO
- EUR is DCF77 Frankfurt 77.5 kHz, Europe, less Portugal and Spain: FEN…KHL
Time References and Zones
UTC is Universal Time Coordinated, or Zulu Military Time. It is not a time zone but a global time standard. UTC never observes daylight saving time.
GMT is Greenwich Mean Time, a time standard based on the mean solar time in Greenwich. GMT used to be the global reference. GMT is a time zone and GMT=UTC+0. The UK does observe DST by switching time zone to BST, British Standard Time during summer, which is GMT+1. Some people may call that GMT too which is confusing.
DST is Daylight Saving Time, a modification to a time zone moving the clock 1 hour forward during summer when the days are longer, which is observed in some but not all places.
Quick Daily Cheat Sheet
Time is shown for city shown on the left LCD. Swap it with the right LCD using C1 – A+B.
Modify all zones, and DST specific to the zone on right LCD using C2 – B to cycle and A and C rotation to change.
References
- EG_U600_EN_A U600 quickref (somewhat confusing with chosen terminology though)
- U600_ebook manual
created: 20251116