>Our MRC 600 opens the laser shutter spontaneously when, or shortly
>after, the scan head is turned on.  Sometimes it will do this again
>if the scanning is stopped (though the software).  This only happens
>in the first 5 minutes after switch-on - after that everything is fine.
>It's a trivial matter - *except* that if someone happened to do the
>wrong thing with the sliders on the microscope they could get a
>proportion of the laser beam coming out of the eyepieces, and this
>worries our safety officer.
>
>BioRad initially advised us that replacement of a particular ic with
>a different one (details of which I have somewhere) would fix the
>problem - it didn't.  Neither did a visit from a BioRad engineer who
>changed some boards.
>
>Do other BioRad users have this problem?  It doesn't affect everyday
>operation, and I'm not really too worried about it, since we drum in
>to all users not to put the sliders so that laser light could reach the
>eye, but it would keep our Safety Officer happier if we could find a
>fix.
>                        Guy Cox
>                        [log in to unmask]
>
 
Our MRC-600 experiences the same problem. We have all of the equipment used
for the confocal microscope (Scanhead and computer workstation) on a power
strip supply so that all that is needed to power the scan head and boot the
computer is to turn on the power strip. Many times as soon as power is
supplied to the scan head, the shutter opens and the scanning LED truns on.
If the laser happens to be powered up which is not always the case, you can
see the laser emitting through the objectives. This doesn't happen every
time, and to stop it when it does happen, requires you to go into COMOS. As
soon as COMOS boots up, the shutter is reset, and we don't see the problem
again unless the whole power strip is shut off and then turned on again some
time later.
 
I asked a Bio-Rad Rep. about it once and he told me that it was a power
spike problem to the shutter electronics when the scan head gets an initial
surge of power. Other than that, I have received no other explanantion.
 
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+ Brett Schroeder                            8701 Watertown Plank Road +
+ Dept. of Cellular Biology & Anatomy     Milwaukee, WI 53226-4801 USA +
+ Medical College of Wisconsin                          (414) 456-8504 +
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