Quartzlock A3-B Instruction Manual

Model A3-B Operation And Service Manual
A3-B Manual 30 November 2005 Page 1 of 5
MODEL A3-B
Quartz Oscillator Frequency Standard
USER’S HANDBOOK
Quartzlock UK Ltd
Gothic,
Plymouth Road,
Totnes,
Devon
TQ9 5LH,
England.
Tel: [phone]
Fax: [phone]
Web: www.quartzlock.com
E-mail: [email protected]

Model A3-B Operation And Service Manual
A3-B Manual 30 November 2005 Page 2 of 5
Contents
Safety Considerations..........................................................................................................3
Voltage, Frequency and Power Characteristics...................................................................4
Environmental Conditions....................................................................................................4
Replaceable Fusing Characteristics.....................................................................................4
Cleaning Instructions ...........................................................................................................4
Model A3-B Quartz Oscillator ..............................................................................................5
Introduction ......................................................................................................................5
Facilities Available............................................................................................................5
Front Panel...................................................................................................................5
Back Panel ...................................................................................................................5
Very Long Term Frequency Adjustments.........................................................................5
Appendix..............................................................................Error! Bookmark not defined.

Model A3-B Operation And Service Manual
A3-B Manual 30 November 2005 Page 3 of 5
Safety Considerations
General
This product and related documentation must be reviewed for familiarisation before operation. If
the equipment is used in a manner not specified by the manufacturer, the protection provided by the
instrument may be impaired.
Before Applying Power
Verify that the product is set to match the available line voltage and the correct fuse is installed.
Before Cleaning
Disconnect the product from operating power before cleaning.
WARNING
Bodily injury or death may result from failure to heed a warning. Do not proceed beyond a warning
until the indicated conditions are fully understood and met.
CAUTION
Damage to equipment, or incorrect measurement data, may result from failure to heed a caution. Do
not proceed beyond a caution until the indicated conditions are fully understood and met.
This equipment must be earthed
An uninterruptible safety earth ground must be maintained from the mains power source to the
product’s ground circuitry.
WARNING
When measuring power line signals, be extremely careful and use a step down isolation transformer
whose output is compatible with the input measurement capabilities of this product. The product’s
front and rear panels are typically at earth ground. Thus, never try to measure AC power line
signals without an isolation transformer.
WARNING
Instructions for adjustments when covers are removed and for servicing are for use by service-
trained personnel only. To avoid dangerous electrical shock, do not perform such adjustments or
servicing unless qualified to do so.
WARNING
Any interruption of the protective grounding conductor (inside or outside the instrument) or
disconnecting of the protective earth terminal will cause a potential shock hazard that could result
in personal injury. Grounding one conductor of a two conductor out-let is not sufficient protection.
Whenever it is likely that the protection has been impaired, the instrument must be made
inoperative and be secured against any unintended operation.
If the instrument is to be energised via an autotransformer (for voltage reduction) make sure the
common terminal is connected to the earthed pole terminal (neutral) of the power source.
Instructions for adjustments while the covers are removed and for servicing are for use by service-
trained personnel only. To avoid dangerous electrical shock, do not perform such adjustments or
servicing unless qualified to do so.

Model A3-B Operation And Service Manual
A3-B Manual 30 November 2005 Page 4 of 5
For continued protections against fire, replace the line fuse(s) with fuses of the same current rating
and type (for example, normal blow time delay). Do not use repaired fuses of short-circuited fuse
holders.
Voltage, Frequency and Power Characteristics
Voltage 220-240V AC
Frequency 40-50Hz
Power characteristics 500mA Max
Environmental Conditions
Temperature
Operating (ambient) -10°C to +55°C (-65 to +65 op)
Storage -40°C to +85°C
Magnetic Field
Sensitivity ≤2x10-11/ Gauss
Atmospheric Pressure -60m to 4000m
<1x10-13/ mbar
Replaceable Fusing Characteristics
800mA time-lag HBC
Cleaning Instructions
To ensure long and trouble operation, keep the unit free from dust and use care with liquids around
the unit.
Be careful not to spill liquids onto the unit. If the unit does get wet, turn the power off immediately
and let the unit dry completely before turning it on again.
Clean with a damp (with water) cloth.
Never spray cleaner directly onto the unit or let liquid run into any part of it. Never use harsh or
caustic products to clean the unit.

Model A3-B Operation And Service Manual
A3-B Manual 30 November 2005 Page 5 of 5
Model A3-B Quartz Oscillator
Introduction
The Model 3 quartz frequency standard is based upon a new design of oven controlled crystal
oscillator and will give excellent service over long time periods. The unit is fed from an external,
switched mode power supply working at 50/60 Hz and supplied from a mains source of between
110 V and 240 V (r.m.s.).
Facilities Available
This equipment is fitted with the following outputs, as standard, all of which have the same
high accuracy as the 10 MHz oscillator itself:
Front Panel
The front panel is fitted with 8 B.N.C sockets on its left hand side, supplying 1, 5 &10MHz sine
wave at a level of +13 dBm into 50Ω; 1, 5, 10MHz square wave at >2V ttl; 1pps sync input; 1
standard optional output.
Back Panel
On the extreme left hand side of the back panel, the XLR power plug should be mated with the
XLR line socket from the external, switched mode power supply. The mains supply should then be
connected to the three pin plug on this switched mode supply. The XLR plug next to it has been
included for the battery backup supply, available as an extra option. If this option is not selected,
then this plug is left unconnected.
Very Long Term Frequency Adjustments
On leaving the factory the unit will have been adjusted against a hydrogen maser frequency
standard, to within 1E-11.
However, it is appreciated that quartz crystal oscillators will tend to drift (upwards) in frequency
over long time periods, due to crystal ageing. Should the customer consider that the drift eventually
renders the unit in need of correction, the following should be carried out:
EITHER
Return the unit to Quartzlock for readjustment against the hydrogen maser there
OR
If a high accuracy frequency standard is locally available, remove the six lid retaining
screws and locate the blue, 10 kR, 20 turn potentiometer, next to the OCXO unit. Very
carefully adjust this potentiometer until the frequency is within acceptable limits. A
comparison frequency standard, whose accuracy is better than 1E-12, is recommended for
this adjustment.