Odd problem with HP 4P

I had one of those, seems to me that it only went to 300 dpi. Anyways I sold
it and bought an HP 6100 ( pretty much like an HP 4c, only newer ) with ADF
for $40.
These are 600 dpi and are built like a tank, almost as big and heavy too!
This information and $1.25 will get you a coffee somewheres. I guess what
I'm saying is, it's not worth fooling with the 4p, get a 4c or 6100 off
ebay, you'll like it.

Doug

"Gregg E." wrote in message
...
I picked up a used HP 4P scanner, which is very nice, except when
attempting to scan at 300 dpi or higher. (Scans at any lower
resolution are perfect!)

What happens is it appears that one or two of the colors in the
scan sensor randomly cuts out, so I get scans with perfect bands
interspersed with horizontal blue, red, purple, yellow or green
tinted bands. It will also sometimes do this when doing the
preview scan.

I did dig up some info that the 5P uses a completely different
sensor for 300 dpi and higher scanning. Is this also true of the
4P? Does this scanner use a rotating color filter instead of an
RGB sensor?

The two metal rails the scanner head slides on were quite dirty
and it didn't slide smoothly, so I used a paper towel and some
silicone grease to clean them, leaving a very thin coating of
the grease on the rails. The head moves silky smooth now.
Unfortunately that didn't fix the problem.

I'm hoping I can fix this 4P because new legal size scanners that
also have the good depth of field for scanning not-flat items
are not cheap, or they are cheap, cheaply constructed that is and
so thin you can only scan paper because their "depth" of field
is exactly the top surface of the glass.