Maintenance
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9-3
Cleaning Radioactive or Biohazardous Materials From the Block
When cleaning machines that have been running radioactive or biohazardous reactions,
consult your institution’s radiation safety officer or biosafety officer regarding cleaning
methods, monitoring, and disposing of contaminated materials.
Changing the Fuses
The circuits in the DNA Engine Tetrad 2 cycler are protected by four fuses (6.3A fast-
acting, 5 x 20 mm). When a fuse blows, the cycler immediately shuts down and
cannot be turned back on. The machine records the event as a power loss. If a pro-
tocol is running when a fuse blows, the machine will resume the run when the fuse is
replaced and the power restored.
Warning:
The DNA Engine Tetrad 2 cycler incorporates neutral fusing,
which means that live power may still be available inside the
unit even when a fuse has blown or been removed. Never open
the DNA Engine Tetrad 2 base. You could receive a serious
electrical shock. Opening the base will also void your warranty.
1. Disconnect the power cord from the back of the instrument. Move the power
switch to the “0” (off) position.
2. Insert a small flat-head screwdriver into the slot in the center of the fuse plug
(figure 9-1A), and gently turn. The plug will disengage. Pull the plug straight out
to expose the fuse (figure 9-1B).
3. Remove all fuses and replace them with new ones (it is often impossible to deter-
mine visually which fuse is blown). You can also test the fuses with an ohmmeter
to determine which is defective and replace just that one.
4. Gently press the fuse plug back into place. Turn and secure with the screwdriver.
Reconnect the power cord.
Figure 9-1
A, How to pull out the fuse plug. B, Location of the fuses in the opened plug.
A
B
Fuse Plug
Screwdriver
Fuse Plug
Fuse
