Problem

I don't know much about this equipment. 

I'm not too knowledgeable about this machinery. 

While challenging due to its specific requirements, these efforts showcase human fascination with nature's mysteries and the determination to preserve and understand the wonders of our world.

Replace lamp , If absorbance out of limits on all filters , if not , absorbance out of limit for one particular filter change the filter , Most probably the this problem will arise for 340nm (trhe filter has become opaque). 

2. Clean the Flow cell , throughly,  The absorbance of  Flow cell with  distilled water , shall not exceed 0.3 in 340 nm