GE UV-1 6. Trouble-shooting

6. Trouble-shooting

The UV-1 Monitor has been designed for trouble-free use. If good chromatographic practice is followed, very little difficulty should be experienced. Clean optical surfaces are essential if low noise levels are to be maintained. The following check list of the most frequent problems is meant to be a guide in trouble-shooting. If the checks in this section are executed and the UV-1 still does not work properly, consult your local GE Healthcare representative.

Symptom	Cause			Remedy
Pilot light does not light	1. Mains cord not plugged in			Check that mains cord is plugged in
	2.		Fuse blown	Replace fuse. If fuse blows again
				immediately consult GE Healthcare representative
	3. No voltage at mains socket			Check by plugging table lamp in

Pilot light on, no recorder 1.			Optical unit not connected	Check that connecting cable is
response			to control unit	plugged in
	2.		Control unit not connected	Check connection between output
			to recorder	terminals and recorder
	3.		Recorder not operating	Check recorder function
	4.		Recorder zero not set correctly	Zero recorder
	5.		Recorder range incorrect	Set recorder range to 10 mV
	6.		Wrong filter	Check that the filter corresponds to
				converter or aperture
	7.		Filter not pushed in fully	Push in filter
	8.		Shutter in place	Remove shutter and insert converter
				or aperture as appropriate

Excessive noise	1.		Poor ground contact	Check contact to ground
	2.		Excess noise on mains supply	Use alternative power source or
				remove source of disturbance
	3.		Recorder connections	Check connection between
			incorrect	output terminals and recorder
	4.		Recorder range incorrect	Set recorder on 10 mV range
	5.		Dirty cell	Clean cell
	6.		Deposits on optical surfaces	Clean filter and converter
				Relocate optical unit in a clean environment
	7.		Solvent with high UV absorption	Change to a more suitable solvent
	8.		Lamp not warmed up	2 h warm-up, in cold room 12 h
	8.	Bubbles passing through the cell		De-gas solvent. Check for leaks
	9.		Aging lamp	Check lamp and replace if necessary

Excessive baseline drift	1.		Variable absorbance gradient	Compensate by use of reference cell
	2.		Contaminated solvent	Use fresh solvent. Check that plastic tubing
				does not leak UV absorbing substances
	3.		Large variation in ambient	Relocate optical unit or remove
			temperature	source of temperature change
	4.		Instrument warm-up	Allow 2 hours warm-up
	5.		Condensation forming in	Flush reference cell with dry gas or
			empty reference	fill it with the appropriate solvent

Long term noise,	1. Variations in ambient temperature			Relocate optical unit or protect
often regular waves in			especially in cold room	from draught
recorder reponse	2. Flow rate variations			Check pump system and column packing
	3. Poor ground contact			Check contact to ground
	4. Bubbles passing cell			De-gas solvent. Check for leaks
	5.		Dirty cell	Clean cell
	6. Deposits on optical surfaces			Clean filter and converter
				Relocate optical unit in a clean environment