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From: bartho@obs.unige.ch (PAUL BARTHOLDI, OBSERVATOIRE DE GENEVE)
Newsgroups: comp.sys.atari.st
Subject: Re: Need help with mouse problem :-(
Message-ID: <714@obs.unige.ch>
Date: 17 Jul 90 09:20:46 GMT
References: <1869@engage.enet.dec.com> <MERTENS@DB0TUI11.BITNET> <907@netmbx.UUCP>
Distribution: comp
Organization: University of Geneva, Switzerland
Lines: 49

In article <907@netmbx.UUCP>, hase@netmbx.UUCP (Hartmut Semken) writes:
> MERTENS@tubvm.cs.tu-berlin.de writes:
> 
>>>>bought used:  the mouse  doesn't work in the horizontal direction.
>>>>It's very strange, but no matter which way I move it, the cursor
>>>>moves to the right.  The vertical axis is OK.  If I move the mouse
> 
> Sounds like "loose cable" to me:
> ...

I have an other interpretation of this problem (based on 25 1040st in my lab
and about half a dozen or more sick mouse ...)  The culprit are the encoders.
The heavy ball drive two wheels that pass through optical 'gates'.  They
each produce two signals that should be dephased by 90 degree.  If this
change too much, then you get your stange observed effects.

Cure :  First clean every thing carefully.  Dust on the axes or the optical
        path can cause the phase error.

	Second, but this is an other story :  with time, i have noticed that
	the optical system performance are changing and this must be readjusted.
	In principle, you find two screews (with red paint ?) at one extremity
	of the optical part, and they should be used to adjust the phase.  Now
	for some reasons, the light emiters and receivers are solidly soldered
	on the printed board, and the screews have no effect any more.  
	The solution we have found is this:  unsolder the four wires going 
	from the printed board to the emiter and receiver, bend them 
	horizontaly, solder on them thin wires that you also solder to the
	printed board at the original place.  They should make some thing like
	a 'Z', in such a way that you can now change the phase with the screews!
	Best try to look at the signals (and phase) with an oscillo !
	If you need a drawing, just ask, the ptt will transmit it.

	If this sounds too much, and the cleaning does'nt works, then I am
	afraid that you better get a new mouse (logitech has one now for the 
	atari for about 60$ [in Switzwerland ...] that should be very
	reliable).

                             Good luck !                 Paul.

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