Possible dead PDA?

[itspip]

I have a Dionex UVD340U PDA that I was using for analysis of phthalates. I noticed a massive jump in noise (+/- 100 mAU) that removed all peaks in my chromatogram. I cleaned the flow cell with IPA, water, and dilute nitric acid to no avail. I have checked the solvents for potential purity issues. I finally removed the column and ran water through and did a gradient check from 100% water to a 1% Acetone solution. I can see the peaks I should with acetone, but the noise is too high to do any work with it.

I am wondering if there is something to check in the PDA, like a photomultiplier tube going bad, or is the detector dead?

Thanks

[vmu]

Maybe it's time to change the lamp. There is no photomultiplier tube in a PDA detector.

[itspip]

Lamp was replaced. Same issue.