laser-lovers@uw-beaver (10/09/85)
From: MRL%PFCVAX@MC We've had a strange intermittent problem with our QMS 1200 printer which no one has been able to track down. The problem is that certain tektronix plot files will produce glitches and the glitches are not always in the same place on the plot. Also, downloaded fonts (for TeX) will intermittently not download properly. Certain characters, i.e. lower case z's for several of the fonts will not be loaded. We have a QMS controller with a DATA PRODUCTS interface connected to a VAX with an ABLE VMZ/LP controller. The line length between the two is 75', although we have been told the longest recommended length is 50'. (Is anyone else using longer, and have you had problems?) We suspect the problem is syncronization related. After several months of sending down dumps and tapes to the QMS engineers, they finally believed me when I said the problem was not in the software. They attempted to replace the controller and update all the firmware. The symptoms did somewhat change after this, but it was never solved. Recently, I reviewed the Able controller manual, and it seemed to indicate that we had it set up for a Centronics interface! I changed the switch position, and our problems appeared to go away. However, after a few weeks it became apparent that the problem had only decreased a great deal, but had not totally disappeared. Another look at the Able manual showed a conflict as to which dip switch setting was proper. It turned out that the first reading was wrong, and that the orginal dip switch setting we had was correct! (For those of you with an Able controller, the mistake is on the first page of Appendix F.) Our next step is probably to order a smaller cable length and see if that helps. Has anybody else heard of such a problem? We've had this problem for over 8 months, so any help would be much appreciated! Mark London (P.s. I'm not on the mailing list as yet, so please send mail to MRL%PFCVAX@MC).