4pcs M402SD07GS VFD VACUUM FLUORESCENT DISPLAY MODULE

4pcs M402SD07GS VFD VACUUM FLUORESCENT DISPLAY MODULE , all are in working condition ,  2 work but are very dim

please read this before buying as 2 are very dim compare to the other 2.  with no power , no pixle burning is visable. but power on the 2 dim units have some very dim pixles. all have some pixles burned which are dimmer that others.