Bio-Rad Helios® Gene Gun System - Manual (Page 29)

c. Pull back and hold the cylinder advance lever to retract the inner barrel sleeve into the
gun barrel (Figure 13).
d. Place the empty cartridge holder into the Gene Gun with the position 12 label facing up
and the numbered side of the cartridge holder facing the exit nozzle of the barrel
(Figure 12).
e. When the cartridge holder is in its correct position, the knob on the backside of the car-
tridge holder will slip into the notch on the barrel plate and the cartridge holder will
be flush with the barrel plate.
f. Release the cylinder advance lever; the O-ring on the inner barrel sleeve should hold the
cartridge holder in position.
g. Unlatch the cylinder lock; it should snap into position and the barrel pin should be
inserted into the center hole in the cartridge holder.
h. Push the push bar in; it should snap back into position and engage the cartridge holder
in one of the deep crevices (see Figure 14).
Fig. 14. Correct assembly of the cartridge holder in the Gene Gun in preparation for discharge.
Releasing the cylinder advance lever moves the barrel liner backward, bringing the O-ring on the back
of the liner in contact with the cartridge holder. Releasing the cylinder lock inserts the locking pin into the
center hole in the cartridge holder.
i. Push in and release the cylinder advance lever to ratchet the cartridge holder one position,
bringing the first cartridge into firing position. The number 12 should be seen at the top
point of the cartridge holder. The Gene Gun is now ready for pressurizing with helium.
Note: do not wiggle the cartridge holder after the cartridge is in firing position. The
Helios Gene Gun has a self-centering mechanism which places the cartridge in the proper
position for firing.
2. Set up the Helios Gene Gun and connect to a helium source as described in Section 4.2.
Refer to Section 3.2 for identification of controls on the Gene Gun.
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