MJ Research PTC-0200, Operation Manual

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Operation
ever possible, use high-quality thin-wall tubes intended for thermal cycling
(see chapter appendix 4-A for a tube and plate selection chart).
Using the Optional Probe
The probe consists of a precision thermistor mounted in a thin-walled
plastic tube. A thin wire, encased in a small plastic tube, runs from the
thermistor to the probe’s plug, which is inserted into a slot at the back of
the Alpha unit (fig. 4-3). A small amount of oil is added to the probe tube
to serve as the representative sample. The tube is loaded into the block,
where it can serve as the control reference for any programmed target
temperature between 0˚ and 100˚C.
When a probe-control protocol is run, the DNA Engine controls block
temperature to keep the probe vessel at the programmed temperature,
using feedback information from the thermistor. (See chapters 5 and 6
for information on programming protocols for probe control.)
Note: Note:
Note: Note:
Note: Because the thermal characteristics of a probe can never precisely
match those of a sample, calculated control is often a better choice than
probe control.
Customizing the Probe Vessel
For the most precise control of sample temperatures, install the probe’s
thermistor in the same type of tube that the samples will be placed in.
This is particularly important when the sample tubes have much thicker
walls than the probe’s tube.
Follow these steps to customize the probe vessel:
1. Cut the hinge to the probe tube’s lid, if there is one. Remove the lid
and the attached the amber-colored thermistor.
2. Remove the lid from the new probe tube. Add oil to the probe tube as
described below under “Adding the Oil.”
3. Gently place the thermistor in the new tube, and snap the lid closed.
Make sure that the lid from the original probe tube fits the new tube
tightly . The probe wire may touch the sides of the tube. The ther-
mistor should rest on the bottom of the tube.
Caution: Caution:
Caution: Caution:
Caution: The thermistor is extremely fragile. Handle it with great care.