High background noise

[SeeDawg]

We are having problems with excessively high background noise on our ESA coulochem III HPLC system. Our background current is now about 2.3 nanoamps (should be around 1) and has been as high as 5 on certain days. Our standards look okay but once we start running samples the noise gets worse and we lose our signal. We have exhaused the suggested troubleshooting tips in the manual (e.g. Methanol washes, changing MP, buying brand new components of MP, double checking that pH is correct, doing 1000mv stim for 15 min, etc.) and have replaced the MD cell, pulse dampner, and precolumn filter. We are about to try replacing the column and guard cell but are not sure if this is the problem or will help. Does anyone have any suggestions? Thanks!

[unmgvar]

what are your samples made of?
is there a difference between the mobile phase and the diluent used for the samples?

[Ricobachtiar]

i have the same problem like yours. The background noise was very terrible. i lost my signal... . Is there any solution?