Bio-Rad CHEF-DR® III Variable Angle System - Manual (Page 30)

Section 6
Maintenance of Equipment
6.1 Replacing Electrodes
The gel chamber requires little maintenance except rinsing after every run. Dirt and other
build-up can be removed with laboratory detergent and a fine cloth. Do not bend or break the
electrodes.
Fast switch times (<2 seconds) with high voltage gradients (6-9 V/cm) may lead to
increased electrode failure If one of the electrodes should break, or leak at the O-ring, it may
be replaced. Additional electrodes (catalog number 170-3648) are available from Bio-Rad
Laboratories.
To replace an electrode, turn the gel chamber upside down and remove the six screws. Lift
off the base plate. Remove the hexagonal nut on the wire of the broken electrode, then remove
the hexagonal nut on the electrode to be replaced. Push down firmly on the post to remove the
old electrode. Turn the box over, insert the new electrode, pack with self-leveling silicone
sealant (RTV-type silicone sealer available at most hardware stores), and replace the nut.
Replace the wire and base plate.
If one of the pins to the serial cable bends, use tweezers to carefully straighten it.
Replacement cables may be ordered from Bio-Rad.
6.2 Fuses
If the DC current during a run exceeds 500 mA entering the gel chamber, the 0.5 ampere
FB (fast blow) fuse will blow, and error code F2 will be displayed. Replace the fuse by
unscrewing the cartridge at the front of the drive module. Replace with 0.5 ampere FB fuse
(2 replacement fuses are provided). Make sure the external power supply is off when replac-
ing a fuse.
A power surge may cause the SB (slow blow) line fuse to blow. The LED lights on the
power module will go off. The fuse is at the rear of the drive module. Replace the fuse with
a 3.15 A SB if your line voltage is 100 or 120 VAC, or a 1.6 A SB if your line voltage is 220
or 240 VAC. A 10 Amp fuse is used on the neutral side for 100 and 120 VAC.
Replacement fuses are available from a variety of sources, including Radio Shack ® (Tandy
Corporation). The 0.5 A FB fuse can be obtained as catalog number 270-1241, and the 3.15
A SB as catalog number 270-1173 from Radio Shack.
If the unit still does not operate, contact Bio-Rad Laboratories. Do not attempt to open and
repair the power module, or the warranty may be voided.
6.3 Maintenance of the Electrophoresis Cell
When the cell is not in use, even for short periods, all buffer should be removed to pre-
vent damage to the plastics. In addition, the lid should be left slightly opened to minimize
possible warpage.
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