Redback Q 2003 User manual

www.altronics.com.au
Operating Manual
Q 2003 Impedance Meter
FEATURES:
• 16 x 2 LCD shows impedance, 100V and 70V load value.
• 1Ω to 19KΩ test range
• Single push button operation.
• Auto ranging.
• Inbuilt Battery charger circuit.
• Display accuracy +/-10%.
• Low battery indication.
• Backlit display.
• Rugged yet easy to hold hand held case.
• Easy battery replacement.
• System test mode.
INTRODUCTION:
Measuring a transformer with a regular ohm meter or
multimeter is very difcult and provides inaccurate results.
This is because an ohm meter or multimeter uses DC to
measure the resistance.
Consider a transformer, which is basically a coil of wire, the
DC resistance will be fairly low. If an AC signal is passed
through the winding the impedance will be much higher,
unless the winding is shorted. In this case the reading will
be very low.
In the case of a short circuit the inductance of the transformer
tries to impede the current ow through the winding. The
nature of transformers will result in the impedance being
reected into other windings on the transformer being
tested. This means a shorted turn on any winding will show
up on the other windings.
An impedance meter is also critical for accurately measuring
low impedance loudspeaker systems, incorporating multiple
speakers and crossovers, and for measuring commercial 100V
line speaker systems, which may include many speakers with
line transformers and several hundred meters of cable. Trying
to measure this type of load is virtually impossible with a
standard multimeter.
For example a short circuit on several hundred metres of cable
will not show up as a short circuit on a standard multimeter.
You will actually measure the DC resistance of the cable
which will be around 22 ohms for 500 meters of 24/0.2
cable.
Using an impedance meter, measuring the AC resistance will
read a short circuit. A short circuit located remotely in a
speaker line is the major cause for ampliers overheating
and blowing DC fuses.
Shorted turns on mains transformers primary windings can
also be measured with this meter. If this meter displays
a value of less than 100 ohms, this will indicate that the
transformer has a shorted turn.
OPERATION:
TO MEASURE IMPEDANCE
Make sure the amplier has been completely disconnected
from the line to be measured.
Connect the test leads to the Q 2003.
Connect the test leads to the speaker line.
Once your meter is connected press the TEST button for
approximately 1 second (or 2 seconds if the LCD backlight
is required). The impedance meter will display “CHECKING
LOAD” for approximately 3 seconds while it checks the
speaker load. You will be able to hear a tone from the speaker
load that is under test. After 3 seconds the load impedance
will be displayed on the LCD along with the 100V load value.
After 8 seconds the 70V load value will replace the 100V
load value on the LCD.
User manual revision number 1.0 04/01/2017

www.altronics.com.au
Redback® Proudly Made In Australia
2
* Specications subject to change without notice.
Distributed by Altronic Distributors Pty. Ltd. Perth. Western Australia. Phone: [phone] Fax: [phone]
SYSTEM CHECK MODE
System check Mode is included for audible testing of
larger speaker installations. It allows the Q 2003 to run at
full output for a period of approximately 6 minutes so the
installer can walk around the install to check sound is present
on all speakers.
To activate this mode connect the test leads to the load to be
checked, ensure that an amplier is not connected. Make
sure the Q 2003 is OFF then press the TEST button and hold
for 5 seconds. “SYSTEM CHECK” will display on the LCD
and a 1kHz tone will be put out the test leads.
SWITCHING OFF
To switch off the Q 2003 all you need to do is press the TEST
button again. The LCD will display “OFF” for a short time
then the unit will power down. The Q 2003 is also equipped
with an auto power off function. The unit will automatically
power down after a period of 20 seconds in Single test
mode and 6 minutes in System check mode, saving precious
battery life.
BATTERY INSTALLATION AND OR CHARGING
“LOW BATTERY” will display on the LCD when the battery
requires replacing or if a rechargeable 9V Nicad/Nimh battery
(such as the Altronics S 4740C, not supplied) needs charging.
To replace or install the 9V (type 216) battery required to
power the Impedance Meter, simply slide off the battery
compartment on the back of the unit. Remove and unclip
the old battery from the connector and replace it with a fresh
battery. Slide the cover back until it locks into place.
To recharge an installed Nicad/Nimh battery connect a
12VDC source (car battery, cigarette lighter socket or plug
pack) >300mA with a 2.1mm centre positive plug to the
charging socket located on the top of the Q 2003.
“CHARGING” will display on the LCD along with the charge
%. When the charge % reaches 100%, the unit will stop
charging and display “CHARGE FINISHED” on the LCD. The
charger can then be unplugged. The inbuilt charging circuit
is a slow charger and will take up to 12 hours to charge a
completely at battery.
NOTE:
1) The Q 2003 will not function as an Impedance meter when
charging.
2) The charger can be removed at anytime during charging
though battery life will suffer.
3) The Q 2003 will still function when “LOW BATTERY” is
being shown on the LCD but the measured results may be
out by as much as 10%.
IMPORTANT GUIDELINES:
Don’t connect the meter to a line that has an amplier
attached to it. The impedance of the output transformer
of an amplier is extremely low and you could be easily
be looking for a non-existing short.
Don’t connect the meter to an active line. You will
damage the meter with the applied voltage.
Don’t continue to use a battery once the “LOW
BATTERY” is being shown on the LCD. The readings
you will get will be incorrect.
i
Wiring speakers in parallel for 70/100V line: Where several speakers are to
be used at one time, on one circuit, it becomes necessary to use speakers tted
with line-matching transformers. This is to overcome the effects of connecting
speakers in parallel and cable losses. The amplier generally has an output
voltage of 100 volts (70 volts is typically used in North America, however
operation is similar). In this conguration the total wattage load on the amplier
is derived from adding all the line transformer primary tap ratings together. For
example, 70 one watt speakers will have a total speaker load of 70 watts. Or
alternatively, it is conceivable to connect 100 one watt speakers to a 100 watt,
100 volt line amplier.
Measuring 70/100V Line Speaker Impedance: To measure amplier system
load, you must use an impedance meter in order to measure the ac resistance
of the connected speaker network. Impedance cannot be measured with a
standard multimeter, as this measures the dc resistance. Use the Altronics
Q 2001 or similar impedance meter.
About 70V & 100V Line Speaker SystemsLoad 70V 100V
0.5W 9.4kΩ 20kΩ
0.66W 7.12kΩ 15kΩ
1W 4.7kΩ 10kΩ
1.25W 3.76kΩ 8kΩ
2W 2.35kΩ 5kΩ
2.5W 1.88kΩ 4kΩ
3W 1.56kΩ 3.3kΩ
5W 940Ω 2kΩ
7.5W 626Ω 1.3kΩ
10W 470Ω 1kΩ
15W 313Ω 666Ω
20W 235Ω 500Ω
30W 156Ω 333Ω
40W 117Ω 250Ω
60W 78Ω 166Ω
100W 47Ω 100Ω
125W 37Ω 80Ω
250W 19Ω 40Ω
500W 9.4Ω 20Ω