Omega CALIBRE 2628 Quick start guide

2628
2628
2628 A
111/2’’’
Ø 25,60 mm
Version A Version B
123
Height on movement 5.20 mm
Power reserve
Number of jewels
Frequency
Lift angle
44 h
27
4 Hz (28’800 A/h)
30° / 38°
48 h
27
3.5 Hz (25’200 A/h)
38°
CALIBRE
2628
Automatic movement, Co-Axial escapement, date, Time zone function, GMT, COSC-certified,
Omega balance system without index. GMT, hour, minute and second hands in centre.
Technical Guide TG-19-C-006-E D
Produced by : pelrom Date: 09.10.2008 3
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Page
Calibre 2628 1
General information for Calibre 2628 3-4
Date correction / Improvements on version B / Complete balance bridge 3
Torques according to the screw threads / Measuring instruments 3
Technical modifications on version «A» and «B» / Hand fitting / Tools / Lubricants 4
Exploded views for Calibre 2628 7-11
Dial side 7
Spare parts list for Calibre 2628 11-14
Spare parts list 11
Specific information for Calibre 2628 15-19
Assembling of escapement system / Lubrication of the escapement 15
Contents
Movement side 8
Movement side 9
Dial side 10
Assembling of the balance bridge / Disassembling of the balance bridge 16
Runners for hands setting and hand setting force / Height of hands 17
Components not requiring epilam coating 18
Special parameter settings / Timing key 19
Spare parts list 12
Spare parts list 13
Spare parts list 14
Differences between calibre 2628A and 2628B 5-6
Differences between calibres 5-6
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OMEGA SA WORLD SERVICE ORGANIZATION GT-19-C-006-E - D - 2628 /3
Date correction
The date Correction is not recommended between 10 p.m.
and 2 a.m.
Improvements on version B
Complete balance bridge (Ref. 10.058°)
Chronometer balance bridges are not available
(see CS-Info. Calibre No. 33).
Tightening and untightening torques according to screw
thread size
Screw Ø Tightening torque target cNm Untightening torque mini cNm
Øthreads ≤S 0.50 mm 1.0 0.7
Øthreads S 0.6 mm 1.4 0.8
Øthreads S 0.7 mm 1.8 0.9
Øthreads S 0.8 mm 2.2 1.1
Øthreads S 0.9 mm 2.6 1.3
Øthreads S 1.0 mm 3.0 1.6
Øthreads S 1.2 mm 3.5 2.0
Øthreads S 1.4 and > 4.0 2.5
Type of intervention and the required
«Measure Instrument»
General information for Calibre 2628
Version A Version B
Quality of adjustment:
Good
Quality of adjustment:
Improved
Self-starting: Medium Self-starting: Good
Interventions Minimum equipment required Comments
Complete or Partial maintenance
service Co-Axial 3.5 Hz & 4 Hz
- Watch Expert II (White case)
- Chronoscope M1 (up-dated version)
- Chronoscope S1
Rate adjustment on new watches:
(Co-Axial 3.5 Hz & 4 Hz)
- Watch Expert (red case)
- Wicometer Professionnel
- Chronoscope M1 (old version)
Important: The amplitude will
not be indicated precisely.
This is acceptable for the
rate adjustment only!

OMEGA SA WORLD SERVICE ORGANIZATION GT-19-C-006-E - D - 2628 /4
General information for Calibre 2628
Technical modifications on version «A» and «B»
Hand fitting
To fit the hands, the movement must be placed in a suitable,
well-adjusted movement holder.
Tools Ref.
Hand fitting tool kit 507 0011
Movement holder for hand fitting 507 0017
Mainspring winder 502 150 0009
Timing key 506 0042
Tool for checking the escapement
functions 506 0002
Ball bearing set 502 S03 SET
Key-bolt key for oscillating weight 502 200 0361
Holder for oscillating weight 502 100 0381
Lubricants Ref.
Moebius SYNT-A-LUBE 9010 (2ml) 504 200 0001
Moebius HP-500 504 5012
Moebius SYNT HP-1300 Sans Colorant 504 5013
Moebius 9504 504 5014
Kluber P125 504 100 0071
Lubeta V105 504 5005
Intermediate escape wheel
Old version Risk New version Improvements Notes
7222500C30039
Black residues within
the engagement can
cause low amplitude or
a stop of the watch.
The old version is yellow.
7222500C30039
Improvement of surface
and material.
The new version is grey.
Available since 21/2008
The new version must
automatically be assembled
if black residues within the
engagement are visible.

2628A (4 Hz) 2628B (3.5 Hz)
Mainplate
ref. 72226281002007
Engraving 2628A
ref. 7222628B81002007
Engraving 2628B
Balance bridge
ref. 7222500B10058° ref. 7222500C10058°
Barrel, complete
ref. 7222500B20010 ref. 722112020010
Mainspring
ref. 7222500B20102 ref. 722112020102
Oscillating weight
2628
2628
ref. 72226282201006
2628B
2628B
ref. 7222628B2201006
Second wheel
ref. 722112830027*
96 teeth and eight arms
ref. 7222628B30027*
105 teeth and five arms
Intermediate escape wheel
ref. 7222500B30039
8-leaf pinion
ref. 7222500C30039
10-leaf pinion
Cutout in upper pivot shank
Co-Axial wheel
ref. 7222500B30040
Pinion Ø = 1.999 mm
ref. 7222500C30040
Pinion Ø = 2.119 mm
Pallet fork
Old shape
ref. 7222500B40010
New shape
ref. 7222500C40010
Differences between versions 2628A and 2628B
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Differences between versions 2628A and 2628B
2628A (4 Hz) 2628B (3.5 Hz)
Balance complete with stud
Inertia
Diameter
Balance rim thickness
Pivots
Shock absorber
Rate correction with 1 screw-revolution (on both screws)
ref. 7222500B4005021
7.2 (mgcm2)
8.54 mm
0.37 mm
0.08 mm cylindrical
0.09 mm = pivot hole Ø
57 seconds
ref. 7222500C4005021
9.4 (mgcm2)
8.70 mm
0.45 mm
0.07 mm conical
0.08 mm = pivot hole Ø
86 seconds
Stop lever
ref. 722250056070 ref. 7222500C56070
Shock-absorber, upper
ref. 722112070530 ref. 7222500C70530
Shock-absorber, lower
ref. 722112070531 ref. 7222500C70531
In settings, upper
ref. 722112070640 ref. 7222500C70640
In settings, lower
ref. 722112070641 ref. 7222500C70641
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Parts listed in order of assembly
1 = 31120
2 = 31121
3 = 5101021
4 = 53022
5 = 5108006
6 = 51050
7 = 51091
8 = 3503 (1x)
9 = 31100
9
5
8
7
4
6
3
1
2
Moebius SYNT HP-1300 Sans Colorant
Moebius 9504
Exploded views - Dial side for Calibre 2628
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8
7
6
5
1
3
11
12
18
17
16
15
14
19
920
24
25
10
21
4
23
22
Versions A&B
see page 5
Restrictions:
see page 3
Versions A&B
see page 6
2
13
See page 15
Versions A&B
see page 5
Versions A&B
see page 5
Versions A&B
see page 5
Parts listed in order of assembly
1 = 1004107
2 = 32033
3 = 31023
4 = 31024
5 = 31021
6 = 51120
7 = 81036
8 = 3509 (1x)
9 = 30012
10 = 20010
11 = 31020
12 = 1004107
13 = 3503 (3x)
14 = 30039
15 = 30025
16 = 30027*
17 = 1004807
18 = 3505 (1x)
19 = 30040
20 = 40010
21 = 1005707
22 = 3511 (1x)
23 = 3511 (1x)
24 = 10058°
4005021
Moebius SYNT-A-LUBE 9010
Moebius SYNT HP-1300 Sans Colorant
Moebius SYNT HP-500
Moebius SYNT HP-1300 Sans Colorant
Kluber P125
Exploded views - Movement side for Calibre 2628
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Parts listed in order of assembly
1 = 56070
2 = 1203007
3 = 32032
4 = 32031
5 = 32037
6 = 52040
7 = 1205107
8 = 3504 (1x)
9 = 2201006
10 = 3507 (3x)
11 = 3503 (3x)
12 = 52041
13 = 12124
14 = 3506 (1x)
11
12
14
13
1
2
3
4
5
6
9
7
8
10
11
2628
2628
Versions A&B
see page 6
See CS-Info Calibre no. 26 Lubeta V105
When Lubeta V105 is available, do not
use Moebius 9010
Moebius SYNT-A-LUBE 9010
Moebius SYNT HP-1300 Sans Colorant
OMEGA SA WORLD SERVICE ORGANIZATION GT-19-C-006-E - D - 2628
Exploded views - Movement side for Calibre 2628
/9

Parts listed in order of assembly
1 = 31083*
2 = 31041
3 = 31100
4 = 31101
5 = 10062
6 = 3503 (1x)
7 = 31101
8 = 33032
9 = 31046*
10 = 33014
11 = 1601006
12 = 3502 (3x)
13 = 91440
14 = 53080
15 = 13111
16 = 3501 (1x)
17 = 13105 (2x)
18 = 3500 (2x)
19 = 3104706*
Moebius 9010
Moebius SYNT HP-1300 Sans Colorant
Moebius SYNT HP-1300 Sans Colorant
Moebius 9504
OMEGA SA WORLD SERVICE ORGANIZATION GT-19-C-006-E - D - 2628
Exploded views - Dial side for Calibre 2628
/10
*
5
6
2
1
7
3
15
16
18
14
8
10
19
13
17
11
12
4
9
Additional lubrication:
See CS-Info Calibre no. 32
Lubrication spot (Moebius 9010, small quantity)
at the exit of the second wheel axe - centre tube.

Main plate, pre-assembled Version Reference Reverser maintaining plate Version Reference
2628A 72226281002007 2628A
722112012124
2628B 7222628B1002007 2628B
Barrel bridge Version Reference Date indicator maintaining plate Version Reference
2628A
7222500B1004107
2628A
722112813105
2628B 2628B
Wheel train bridge Version Reference Date jumper maintaining plate Version Reference
2628A
7222500B1004807
2628A
722112813111
2628B
2628B
Pallet bridge, pre-assembled Version Reference Display mechanism
platform, assembled Version Reference
2628A
72225001005707
2628A
72226281601006
2628B 2628B
Balance bridge Version Reference Barrel complete Version Reference
2628A 7222500B1005824 2628A 7222500B20010
2628B 7222500C1005824 2628B 722112020010
Minute train bridge Version Reference Barrel drum and cover Version Reference
2628A
722112810062
2628A
722112020030
2628B
2628B
Dial fastener Version Reference Barrel arbor Version Reference
2628A 722112010300 2628A 722112020060
2628B
2628B
Upper automatic bridge Version Reference Mainspring Version Reference
2628A
7222500B1203007
2628A 7222500B20102
2628B 2628B 722112020102
Lower automatic bridge Version Reference Oscillating weight, assembled Version Reference
2628A
72211201205107
2628B
2628B
2628A 72226282201006
2628B 2628B 7222628B2201006
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Spare parts list for Calibre 2628
/11

OMEGA SA WORLD SERVICE ORGANIZATION GT-19-C-006-E - D - 2628
Spare parts list for Calibre 2628
/12
Ball bearing Version Reference Hour wheel Version Reference
2628A
722112022040
2628A
722112831046*
2628B 2628B
Oscillating weight bolt Version Reference Hour wheel, 24 hours Version Reference
2628A
722112022042
2628A
72211203104706*
2628B 2628B
Intermediate wheel Version Reference Cannon pinion with driving wheel Version Reference
2628A
722112030012
2628A
722112831083*
2628B 2628B
Third wheel Version Reference Setting wheel Version Reference
2628A
722112030025
2628A
722112831100
2628B 2628B
Second wheel Version Reference Intermediate setting wheel Version Reference
2628A 722112830027* 2628A
722112831101
2628B 7222628B30027* 2628B
Intermediate escape wheel Version Reference Winding pinion Version Reference
2628A 7222500B30039 2628A
722112831120
2628B 7222500C30039 2628B
Co-Axial wheel Version Reference Sliding pinion Version Reference
2628A 7222500B30040 2628A
722112831121
2628B 7222500C30040 2628B
Ratchet wheel Version Reference Reduction wheel Version Reference
2628A
722112031020
2628A
722112032031
2628B 2628B
Intermediate ratchet wheel Version Reference Intermediate reduction wheel Version Reference
2628A
722112031021
2628A
722112032032
2628B 2628B
Crown wheel Version Reference Ratchet wheel driving wheel Version Reference
2628A
722112031023
2628A
722112032033
2628B 2628B
Intermediate crown wheel Version Reference Reversing wheel Version Reference
2628A
722112031024
2628A
722112032037
2628B 2628B
Minute wheel Version Reference Intermediate date wheel Version Reference
2628A
722112831041
2628A
722112833014
2628B 2628B

OMEGA SA WORLD SERVICE ORGANIZATION GT-19-C-006-E - D - 2628
Spare parts list for Calibre 2628
/13
Date wheel Version Reference Stop lever Version Reference
2628A
722112833032
2628A 722250056070
2628B 2628B 7222500C56070
Pallet fork Version Reference Shock-absorber, upper Version Reference
2628A 7222500B40010 2628A 722112070530
2628B 7222500C40010 2628B 7222500C70530
Balance complete with stud Version Reference Shock-absorber, lower Version Reference
2628A 7222500B4005021 2628A 722112070640
2628B 7222500C4005021 2628B 7222500C70640
Stud support Version Reference In settings, upper Version Reference
2628A 7222500B40200 2628A 722112070531
2628B 2628B 7222500C70531
Winding stem Version Reference In settings, lower Version Reference
2628A 72211285101021 2628A 722112070641
2628B 2628B 7222500C70641
Yoke Version Reference Cap jewel, upper Version Reference
2628A 722112051050 2628A 722112070900
2628B 2628B
Setting lever Version Reference Cap jewel, lower Version Reference
2628A 72211285108006 2628A 722112070901
2628B 2628B
Setting lever jumper Version Reference Shock-absorber spring, upper Version Reference
2628A 722112051091 2628A 722112078004
2628B 2628B
Click Version Reference Shock-absorber spring, lower Version Reference
2628A 722112051120 2628A 722112078005
2628B 2628B
Reverser Version Reference Centre tube Version Reference
2628A 722112052040 2628A 722112880400
2628B 2628B
Auxiliary reverser Version Reference Click plate Version Reference
2628A 722112052041 2628A 722112081036
2628B 2628B
Date corrector
operating lever Version Reference Date indicator Version Reference
2628A
722112853022
2628A
722262891440*
2628B 2628B
Date jumper Version Reference Screw for date indicator
maintaining plate Version Reference
2628A 722262853080 2628A 72211283500
2628B 2628B

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Spare parts list for Calibre 2628
/14
Screw for date jumper
maintaining plate Version Reference
2628A 72211283501
2628B
Screw for display
mechanism platform Version Reference
2628A 72211283502
2628B
Screw for setting lever jumper Version Reference
2628A 72211203503
2628B
Screw for minute train bridge Version Reference
2628A 72211203503
2628B
Screw for automatice device Version Reference
2628A 72211203503
2628B
Screw for barrel bridge Version Reference
2628A 72211203503
2628B
Screw for balance bridge Version Reference
2628A 72211203503
2628B
Screw for lower automatic
device bridge Version Reference
2628A 72211203504
2628B
Screw for wheel train bridge Version Reference
2628A 72211203505
2628B
Screw for reverser
maintaining plate Version Reference
2628A 72211203506
2628B
Screw for ball bearing Version Reference
2628A 72211203507
2628B
Screw for click plate Version Reference
2628A 72211203509
2628B
Screw for pallet bridge Version Reference
2628A 72225003511
2628B
Screw for stud Version Reference
2628A
2628B 72225003512

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1
2
3
4
5
Fig. 1.0 1.0 Assembling of the escapement system
Key points
The order of assembly must be respected (See page 11).
After assembling, the escapement functions must be
checked accurately with the corresponding tool.
The pallet bridge positions the co-axial wheel and the pal-
let fork. To ensure the functioning of the escapement it is
necessary to respect the following order of assembly:
1. Position the co-axial wheel.
2. Position the pallet fork.
3. Position the pallet bridge, screw no (4) must be correctly
placed in their beds.
4. To position the pallet bridge, screw no (4) must be fixed
first.
5. The second screw (5) fixes the bridge.
2.1 Assembling of the balance bridge
As the table roller is under the pallet fork, the
balance must be assembled carefully.
1. Position the complete balance bridge
(with balance). The bridge is pointing
towards the center of the movement.
2. Check the position of the balance. The pivot of the
balance-staff must be correctly placed in its bed.
3. Carefully turn the bridge to its normal position.
4. Fix the bridge with its screw.
2.2 Disassembling of the balance bridge
The balance bridge must be disassembled by removing the
parts in the opposite order of procedure 2.2. To avoid any
risk of damaging the balance, the bridge has to be turned
towards the center of the movement. In this position the
bridge may be removed without any risk.
Specific information for Calibre 2628
4
1
2
3
Fig. 2.1
Fig. 2.2

Specific information for Calibre 2628
OMEGA SA WORLD SERVICE ORGANIZATION GT-19-C-006-E - D - 2628
Description Movement holder Nbr. of runners for
hand setting
Minimum force
(N)
Maximum force
(N)
Support
(jewel)
GMT hand
507 0017
710 50 no
Hour hand 510 50 no
Minute hand 210 30 no
Second hand 110 30 yes
3.0 Runners for hand setting and hand
setting force
/16
2628
2628 A
VBXH2 H5
Calibre Ω + version
Hauteur aiguillage (H5)
Code de fabrication
2628
2628
2628 A
VBAH2 H5
Fig. 3.2
3.2 Height of hands
The star next to a supply reference in the part list means
that there are several heights of hands.
e.g.: 722112831083*.
To order movement parts, you must enter the order as fol-
lows:
e.g. : 7221128310835.
The last figure indicates the wheel height.

OMEGA SA WORLD SERVICE ORGANIZATION GT-19-C-006-E - D - 2628
Specific information for Calibre 2628
/17
Description Reference
Balance assembled on the balance bridge * 40055 + 10058°
Complete balance 40055
Pallet fork 40010
In-setting, upper *
In-setting, lower *
70640
70641
Pallet fork bridge 1005707
Barrel complete**
Mainspring
20010
20102
Reversing wheel 32037
* Do not treat the shock-absorber settings with epilam; the cap jewels should however be treated
** Do not treat the complete barrel with epilam, only the drum, cover and arbour separately.
4.0 Components that must not be
epilam-treated after cleaning

Fig. 5.1
REF. 506 0042
Fig. 5.0
Fig. 5.2
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Special parameter settings
Instrument type Co-Axial
4 Hz calibres
Co-Axial
3.5 Hz calibres Comments
Former Witschi instruments
- Watch Expert (red case)
- Wicometer Professional
- Chronoscope M1 (old version)
Lift angle
set to 30°
Lift angle
set to 38° 3.5 Hz calibres:
The frequency parameters
(25’200 A/h) should be
set manually so that the
instantaneous rate is
All measurements
are correct
The amplitude
is not measured
correctly
New Witschi instruments
- Watch Expert II (white case)
- Chronoscope M1 (up-dated version)
- Chronoscope S1
Lift angle
set to 38°
Lift angle
set to 38° Test mode:
Parameters must be set
for «Spe1»!
All measurements
are correct
All measurements
are correct
5.0 Timing key
A special timing key tool has been developed to adjust
the rate even when the movement is cased in. The rate
can be corrected according to the table below by turning
the two balance screws a complete turn. A scale is found
on the outside of the tool. A division corresponds to a rate
correction of 1 second. (according to the table below).
One screw is located between two arms on the balance
which are specially marked by points (see Figure 5.2) for
easy identification of each screw during the correction
process.
Balance
The annular balance has two adjusting micro-screws. A
slow rate deviation is corrected by tightening the micro-
screws (towards the centre of the balance), which redu-
ces its moment of inertia and makes it run faster. A fast
rate deviation is corrected by loosening the micro-screws
(away from the centre of the balance). This increases its
moment of inertia and makes it run slower.
Important:
The rate is always corrected using both adjustment
screws to prevent an unbalance of the balance.
Demagnetise the movement according to Working
Instruction 34.
Values to be checked
Please consult Working Instructions 5 and 28 for
instructions and tolerances.
Version A Version B
One correction turn = 57 seconds One correction turn = 86 seconds
One division = 1 second One division = 1.5 seconds
Specific information for Calibre 2628