[sane-devel] Medion MD9850: scan range & noise probs?

[Henning Meier-Geinitz]

Hi,

I'm cc'ing sane-devel. Please respond to the list. I'm not a parport
expert :-)

On Thu, Oct 30, 2003 at 12:28:33PM +0100, Wolfgang Fabics wrote:
> Henning Meier-Geinitz wrote:
> 
> > Maybe it's just backtracking? I.e. the scanner is too fast for the
> > parallel port. Does the scan head stop shortly when the noise occurs?
> > Or does it even move backe some milimeters?
> 
> Hmmm... hard to say, the steps are very small, ofc. It doesn't move
> back. I'd say that it... uh... hesitates in a way (maybe sometimes stops
> for a split-second) *after* 2 or 3 consecutive "clanks". I.e. the step
> rate remains the same but the steps get smaller for a while (you can
> hear that by the synchronous "uk-uk-uk-.." sound of the stepping motor).
> It definitely doesn't stop *at* a "clank", anyway.
> 
> The result is that if it "clanks" at a certain line of scanned text, the
> image is vertically stretched a bit at that line.

Does the position of the "clanks" change if you run some programs that
use the processor much, e.g. the compiler? Or just move some windows
while scanning. If that changes the position or number of clanks,
that's a sign for backtracking. At least that would be the case with
SCSI and USB scanners.

> I tried all combos of EPP/ECP on the parport, with both EPP 1.7 and 1.9.
> No change. May I ask a silly question here? How can a 1998 scanner that
> was designed for a 1998 parallel port be too fast for a 2003 AthlonXP
> 1400's parallel port? Any other settings I should try? Sorry, but I'm
> really clueless on those scanner things, as you might have noticed
> already ;-)
> 
> Would you consider that backtracking thing sort of an acceptable (if not
> normal) mode of operation? I mean, that noise is *really* loud... but if
> you think it's by all means not related to any SW/driver issues, I'll
> stop bugging you with this. After all, I am well aware that this is not
> the Medion helpdesk ;-)

I'll leave the answers for the parport developers.

Bye,
  Henning