<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Dear all,<div><br></div><div>yesterday I had the Beckman service on my XL-I ( in 2007 upgraded to Proteom Lab). He had to replace the piece on which the Monochromator is screwed. After screwing for more than 13 years the thread on the XL-I side was damaged. </div><div><br></div><div>Today we wanted to run velocity to characterize a polysaccharide using interference. After having started the run with usual settings, the fringe display remained completely dark. Only when increasing the laser duration the fringe picture became brighter but very heterogeneously, bright on the top but dark for the lower fringes. I thought there could be something with the samples. I stopped the run and put in a cell only filled with water. The same problem continued. I took a screen/window print, see below in the word file. You see the heterogeneous picture.</div><div><br></div><div>Note, to have this figure I already had to increase the laser duration to 4.0 (222 ms) at best laser delay (8 hole rotor, cell with water in hole 4). Normally, I scan at laser durations below 1, preferably 0.2-0.6. Note also, with the upgraded software one cannot adjust brightness. </div><div>Usually I use interference at 1000 rpm for absorbance experiments to be run at high speed to check precise cell filling. I never saw this problem before.</div><div><br></div><div>Thank you in advance for your advice.</div><div>Best,</div><div>Christine</div><div>Note, the picture was a bit deformed to make the problem more visible.</div><div><br></div><div></div></body></html>