Subject:
Re: I killed my Epson perfection 1260 photo. Twice.
From:
Gene Heskett ####@####.####
Date:
24 Oct 2002 09:35:01 -0000
Message-Id: <200210240531.01207.gene_heskett@iolinc.net>
On Thursday 24 October 2002 03:46, Gerhard Jaeger wrote:
>Hi there,
>
>now that we have some reports on damaged EPSON devices,
>we should try and find out what is common to them except
>that the scanners are dead. Although I cannot believe that
>the plustek-backend has killed them, we should find out what
>happens.
>Here are some points:
>- scanner stopps, backend segfaults:
> --> what comes first?
> --> syslog messages?
> --> scan settings (area, resolution, color-depth)?
>
>- scanner does not work anymore:
> --> what part has been killed (motor, lamp, sensor)?
>
>To be honest, I think that during the development of
>the driver quite a lot of my test-devices had reached some
>states that were not good for the hardware, but they never
>stopped working! I'm not sure if it is possible to kill the motor
>by setting some strange PWM settings - at least the motor
>won't move.
>
>The other point is, that I do not have any EPSON device,
>so I live from the feedback and settings I got from you out
>there.
>
>Anyway, I hope that we can find out what's going on there,
>but I don't believe, that EPSON will ever admit that they have
>problems with a device...
Of course not Gerhard, it would be bad publicity, so they quietly
honor the warranty up till the last day its valid, & possibly a bit
beyond. Its called damage control.
As to the PWM settings killing a motor, I have my own doubts. I
suspect that motor is capable of gobbling up everything that puny
little PSU can muster up. And a mis-setting of the PWM can
probably run the total motor milliamps up by about an order of
magnitude by introducing a poor duty cycle thats not properly phase
matched from winding to winding. Someone like me, looking at that
on a scope, might find it very educational, but unforch, its not
readily accessable to do so.
>From the clues here, where most have reported it went dead in the
middle of a scan, no light, no motor, no nothing and the carriage
is left sitting in mid-scan, darned near the only thing this old
troubleshooter with 50 years of experience in electronics can
believe is that the PSU died. Virtually nothing else fits the "if
it walks like a duck" etc test anywhere near as well.
I do know that my scanner makes a lot more noise in some modes using
the plustek backend compared to the noise it makes when using the
epson GT-7200 backend from iscan, which BTW I've yet to be able to
fully compile, it always barfs on the iscan gui here. Anyway, the
increased noise level would tend to make me think the motor is
being driven both harder, and possibly a bit out of phase. Could
that increase in current to the motor kill the PSU? Since this
stuff is often designed down to the last 50 milliamps for enough
power to run it and no more, my 'educated' guess, also known as a
SWAG, for Scientific Wild Assed Guess, is a definite maybe.
But lets first see if we can manage to find out a few things, the
most important of which (to confirm my SWAG theory) is what mode in
terms of the instant dpi setting, was it in when it died? Here,
some modes are much noisier than others. If its a mode known to be
noisey, then, uh, its a possibility and we may have to sacrifice
one to look at those waveforms. The LM9832 docs I have are
certainly much less than concise regarding those settings.
--
Cheers, Gene
AMD K6-III@500mhz 320M
Athlon1600XP@1400mhz 512M
99.18% setiathome rank, not too shabby for a WV hillbilly
