5.0 Operating the Colony Counter
To count directly on the surface of the nutrient medium, place the
uncovered culture plate on the culture plate holder. Loosen the two
thumbscrews on the holder to center the culture plate on the count-
ing plate.
Plug the ground contact and the counting probe into either electric
receptacle on the back of the instrument Position the ground con-
tact with magnetic base near the culture plate so that the L-shaped
tip makes contact with the surface of the agar.
Counts are automatically registered by simply touching each colony
with the needle point of the counting probe (Figure 2). To prevent
the possibility of spurious registration resulting from the “entry”
and “exit” of the probe tip into the medium, a pulsed delay circuit
will admit only one count over a short time period. This feature
does not interfere with the maximum counting speed of a skilled
operator.
6.0 Bulb Replacement
The REICHERT DARKFIELD QUEBEC
®
Colony Counter illumina-
tion source is a standard 40watt soft white-type incandescent bulb.
(50Wfor 230V operation)
7.0 Cleaning the Counting Plate
Remove the screw on the left side of the instrument face. Swing
the magnification lens aside and open the black front section at-
tached to the lower hinge. The counting plate is held in place with
four screws attached to the back of the front panel. Loosen the
screws and slip the plate out of the retainer.
Clean the counting plate with a solution of mild detergent and
water. DO NOT USE AN ABRASIVE CLEANSER. It will damage
the white grid on the counting plate.
Dry the counting plate with a lint-free cloth. Place the counting
plate back into the retainer until it is firmly seated. Avoid leaving
fingerprints on the surfaces, they may cause inaccurate readings.
Ensure plate is installed with rulings facing bulb to avoid damage.
Tighten the four screws and return the front section to the operat-
ing position. Replace the screw on the front of the instrument.
The REICHERT DARKFIELD QUEBEC
®
Colony Counter is de-
signed to insure reliability, long life and minimal maintenance.
Contact your local Reichert representative for additional operating
or service information.
7.0 Fuses
The REICHERT DARKFIELD QUEBEC® Colony Counter has two
fuses located in a fuse drawer next to the power switch on the rear
panel. The instrument must be unplugged to allow access to the
fuse drawer.
8.0 Specifications
The REICHERT DARKFIELD QUEBEC® Colony Counter bears
the following marks: UL, cUL • Models 3325 and 3327 are rated
120VAC, 40 watts
• Models 3326 and 3328 are rated 230VAC, 50 watts
Operating Conditions
• Indoor use only
• RH 80% up to 31°C decreasing linearly to 50% RH at 40°C
• Pollution degree 2
• Altitude up to 2,000m
• Temperature 5°C to 40°C
• Main supply voltage ±10%
• Installation CAT II
