Bio-Rad CHEF-DR® III Variable Angle System - Manual (Page 31)

Section 7
Troubleshooting Guide
Problem Solution
Equipment
No power 1. Check fuse at back of power module
2. Check source of A/C power
3. Contact Bio-Rad Laboratories
No voltage across electrodes, 1. Check that lid is on
with AC power light on 2. Check that serial cable is fully inserted at both ends
3. Check that coiled interlock cable is firmly attached
4. Confirm that all leads are properly attached
5. Check HV fuse on front panel (0.5 A FB) and replace
if necessary
6. Check that the unit is not set in pause mode
Gel floats away 1. Pump flow rate is too high. Adjust with Variable
Speed Pump.
No or low buffer flow 1. Look for kink in tubing
2. Check Cooling Module; buffer in the heat exchanger
can freeze if the chiller is cooling, but the pump is not on
3. Check pump connection and if the pump is on
4. Electrophoresis chamber outlet port may be clogged.
Reverse buffer recirculation flow to unclog the ports.
Remove agarose debris from the chamber and restore
the flow to original condition.
Gel band patterns appear very 1. Foreign object in chamber (remove thermometer, etc.)
distorted; lanes very curved, * 2. Insufficient or non-uniform cooling due to low pump
bands sharp, but slanting flow
3. Check that buffer is level with surface of gel. Use
leveling feet.
4. Check that the current is equal for both switch direc-
tions
5. Replace damaged electrode
6. Power module fault; contact Bio-Rad Laboratories
7. Not enough buffer in cell (total should be 2.2 liters)
8. Check to insure the electrophoresis chamber is level
(Section 4.2)
* Slight distortion of the outermost lane is normal
Applications
Bands smeary or fuzzy 1. Excessive heating. Lower the voltage or ionic
strength of the buffer.
2. Improper switch interval. See Section 5.1.
3. Gel percentage too low. Increase.
4. Sample degraded. Impure enzymes, or wash cycles
too short (agarose blocks).
5. Agarose impurities. Consult Bio-Rad.
6. Sample overload. Adjust sample concentration.
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