Troubleshooting  ELECTRICAL  IMAGE QUALITY  MECHANICAL  -12-  PROBLEM CAUSE SOLUTIÓN Bulb does not work.  Plug outlet does not work  Cable not connected  Bulb burned out.  Fuse blown.  Wrong bulb.  Repair by a qualified specialised  technician.  Connect cable.  Replace bulb.  Replace fuse.  Replace by the correct bulb.  Bulb burns out in short  time.  Voltage too high.  Reduce light intensity to a minimum  before turning the microscope on or  off. Bulb burns out immediately. Wrong bulb.  Replace with the correct bulb.  Bulb flickers.  The bulb is not correctly inserted into  the socket.  Bulb about to burn out. Fuse holder not locked into proper  position.  Loose connection at plug outlet.  Insert correctly.  Replace bulb.  Close correctly.  Repair by a qualified specialised  technician.  Fuse blows in short time.  Wrong fuse.  Replace with the appropriate fuse.  Fuse blows immediately.  Short circuit  Repair by a qualified technician.  PROBLEM CAUSE SOLUTIÓN No image.  Nosepiece not positioned properly.  Image too bright.  Turn until clicks into place. Reduce the intensity of the light.  Poor resolution.  Dirty objective.  Dirty eyepiece.  Slide upside down.  Wrong cover slip used with slide. Light too bright.  Dirty condenser.  Clean objective.  Clean eyepiece.  Replace the slide with the cover slip  facing upwards.  Use 0.17mm thick cover slips.  Reduce light intensity or adjust the  diaphragm aperture.  Clean condenser.  Spots in field of view  Dirty eyepiece.  Dirty slide.  Dirty condenser.  Clean eyepiece.  Clean preparation.  Clean condenser.  Uneven illumination of field. Nosepiece not positioned properly.  Diaphragm aperture not sufficiently  open.  Turn until it clicks into place.  Adjust appropriately.  PROBLEM CAUSE SOLUTIÓN It does not stay in focus.  The stage is sliding down on its own. Adjust the tension of the coarse focus  knob. It does not focus. The stopper on the ascending  movement of the stage needs  adjusting.  Readjust the stopper. 