SLA Problem fixed, cause still unknown

From: ralott@CCGATE.HAC.COM
Date: Fri May 08 1998 - 16:50:31 EEST

     A long long time ago, I posted a message about an SLA250 on which the
     laser would power up without a command during idle time. The laser
     was not fully powered, but the fans came on, the lights on the side
     lit up, as if it were in the cool down cycle.
     After a lot of unfruitful part swapping (power supply, controller, and
     I/O card) the laser was finally brought under control by installing a
     switch in series with the wires connecting the laser to the
     For normal operation, the switch is closed. During idle time, the
     switch is open. As long as the switch was open, the laser did not
     power up on its own.
     This morning, after completing a job, the laser had powered off but
     switch was still open. I did some file maintenance on the PC followed
     with a re-boot, and the laser power came on. This indicates that the
     problem still exists, albeit now under control.
     I've given up on finding out why the laser behaves this way, but
     perhaps if anyone else has this problem they can benefit from my
     Rick Lott
     Hughes Space and Communications
     Los Angeles, Calif.

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