[BioC] Limma function plotDensities question

[Pete]

Hi,
I'm still fairly new to all this so this may be a simple question. I have a 
problem sometimes when using the plotDensities function in Limma, in some 
cases the plot produced is on such a scale that the lines are not 
distinguishable. Usually the intensity axis is in the range of -10 :30, 
however ocassionally after a printtip lowes normalisation, or some 
betweenArrayNormalizations, the scale of the graph is -5000:10000 with the 
density peak being a single spike in the middle of the plot.  Is there a way 
to control the axis scale? or is there an easy way to set a minimum and 
maximums for an MA object?


Many thanks

Pete