Digital BW, The Print

Hello,
I am experiencing thin horizontal lines on my prints.  They are 
horizontal relative to the paper, regardless of the orientation of 
the print (lanscape or portrait).  This has appeared on occasion in 
the past, but always resloved itslef after a few test prints.  The 
lines frequently extend beyond the margin of the print.
All nozzle checks, alignments, etc are good.  These are printed 
lines, not banding.  I am using UT2, but did see some lines like 
these recently when I had OEM inks in trying to clear a clog from 
hell.
I seem to recall reading that lines like this can be due to the 
failure of one of the boards and is the end of the line for the 
printer (ug!)  Does this sound like that problem.  Any hope??
(on to a 4000?)
Thanks to all.