Teledyne 3290 - OEM percent oxygen analyzer - Manual (Page 40)

Maintenance Model 3290
Teledyne Analytical Instruments 30
3. Insert a small flat-blade screwdriver into the slot in the receptacle
wall nearest the fuse and gently pry open the fuse receptacle. The
fuse holder will slide out. The fuse in use is visible in the clip.
To open the spare fuse compartment, push on one end until it
slides out.
4. Remove the bad fuse and replace it with a 5 20 mm 0.5 A,
250 VAC, time lag (T) fuse (P/N F1128) for AC units.
5. Replace the fuse holder into its receptacle, pushing in firmly
until it clicks.
6. Restore power to the analyzer.
5.1.2 DC Powered Units
In units with DC power, the fuse is located on the rear panel above
the ON/OFF switch.
1. Place the power switch on the rear panel to the O position.
2. Open the fuse holder by unscrewing and removing the cap
marked FUSE.
3. The fuse is located inside the receptacle, not inside the cap. Both
terminals are on the same end of the fuse. Pull straight out
without twisting to remove the old fuse from the receptacle, and
replace it with a 0.5 A, 125 VDC, very quick acting (FF)
microfuse (P/N F51).
4. Replace the cap by screwing it back into the receptacle.
5. Turn the instrument back on.
5.2 Sensor Installation or Replacement
5.2.1 When to Replace a Sensor
The characteristics of the oxygen sensor show an almost constant
output through their useful life, and then fall off sharply towards zero at
the end. Normally, very little adjustment will be required to keep the
analyzer calibrated properly during the duration of a cell’s useful life.
If the sample being analyzed has a low oxygen concentration, cell
failure will probably be indicated by the inability to properly calibrate
the analyzer. If large adjustments are required to calibrate the