HP 450C Plotter Help

We have 2 different HP 450C plotters in our office. The problem I am having is one of the engineers plotted out a MS Project file on one of the plotters and ever since it plots the color we use for our title blocks (164) as grayscale instead of in color. I compared the pc3 file with the one for the other plotter and the settings seem identical but I am obviously missing something. We use ctb files and both plotters use the same one and the second plotter is printing color 164 in color. Am I missing something simple here?? Thanks in advance for any help.

 

Don't have a 450, but we do have an HP600 here.

If your plotter allows for customizing settings via a panel on the plotter (which the 600 does), then check the Pen Settings (just follow the menu tree) and make sure that it is set to somthing like "Software" rather than a plotter controlled pallete.

 

The 450C doesn't have that front panel where you can check the pen settings. I have tried about everything I know and can't figure it out. We use a plot style table for both of our plotters and the other plotter works fine, so I assume that's not the problem. The pc3 file is set to "Automatic" for the "Color" option on the Options tab. Any more help would be greatly appreciated, I will keep working on it.