[sane-devel] Scannning trouble with HP 2520A

[Brett (Mare) Henley]

I'm still having trouble with what looks like some kind of
data corruption when I scan wide areas with my scanner using
relatively medium to high scan resolutions.

The problem seems to become worse when I use the higher bit depth
aka 10 bits vs 8 bits per colour. It also gets worse if I increase
the resolution or scan a wider area.

The way this manifests is displayed by lines of what looks like noise or
interrupted data about 2 pixels tall all the way across the scan. The progress
bar also pauses in its progress several times before it completes. The
lines are horizontal. When the scan is done, it seems I can piece the image
back together using gimp if I want.

I posted about this problem last week and didn't get a response so I'm hoping
to hear from someone.  If you like I'll send a sample scan to whoever needs
to see it. Don't really think sending it out on the list would be such a cool
idea.

Below are some specifics for your consideration.

OS: FreeBSD 4.6.2
Proc: 550 Mhz PIII, 512 MB ram
SCSI:
aha0 at port 0x330-0x333 irq 15 drq 6 on isa0
aha0: AHA-1542CF FW Rev. C.0 (ID=45) SCSI Host Adapter, SCSI ID 7, 16 CCBs
(the ATA controller is disabled on the motherboard this is the second IRQ and
drq I've used. Neither had any conflics)

Scanner: HP 2520A (AKA HP scanjet 3C)
scanning res 300 DPI - 1200 DPI (1600 DPI lets me get a clean scan for about
a 1/4" in area. :) )

I've seen this problem with every front end I can find, include hptool etc.
I've checked the scsi controller and cabling and tested the scsi subsystem in
every way that I can.

I'm not against the idea that there's a chance the scanner could have a problem
but it sure seems to work great in every other way I can find.

thanks in advance.

Mare