I'm posting this in the hope that someone else has had this problem and maybe can give me something to suggest to GCC and/or Synrad to get it fixed.
I have a 30W GCC Mercury III machine that I've owned since 2013. For some time, it has not made a mark on the first few passes of a raster job or the first few inches of a vector job. It was happening intermittently - maybe once very few weeks or so and always at the beginning of the day. I contacted my California rep and his first reaction was that the tube was bad. I asked him if there was some troubleshooting we could do before I spent $2K and he said that wasn't necessary - it was the tube. I spoke to someone at Jorlink who gave me some things to try - tickle adjustment and firmware update as I recall - but then he decided that it probably was the tube. GCC techs also concurred with that diagnosis. So, I spoke to 3 different people all of whom said it was the tube that need repair.
Since it only happened occasionally, as a workaround until I was ready to shell out, I would put a dummy line of text at the bottom of my art so if the laser didn't fire at first (I run it from bottom to top) it would only partially mark that line of text and would be fully marking by the time it got to the real job.
In anticipation of the May - June busy season, I broke down and I sent my tube to Synrad in April of this year and paid extra to have it expedited so I had it back within 2 weeks. That cost $2300 if you were wondering.
When I got the tube back and reinstalled it, the problem was still there but still only occasionally and Synrad - since the repair was under warranty - took it back. This time it took almost a month to get it returned. Funny how they didn't attack it with the same enthusiasm as when I paid them extra the first time. Synrad claimed that they took longer because they bench tested it for extra long and they sent me the results that showed that they left it firing for 24 hours at a time on one test. Problem is, the problem occurs when the tube was just started for the day and I think they may have missed that part of my explanation of the problem. That issue seems now to be moot - read on.
I reinstalled the tube and now the problem happens on every job but instead of always not marking or cutting the first few passes of a job it also stops marking in the middle of the job and then restarts after several passes.
I thought it was maybe something I did when reinstalling the tube the last time and I checked that the cables, etc were all seated and to be honest, there's not a whole lot that is involved in reinstalling the tube.
I'm basically out of business now and waiting to hear back from both GCC and Synrad. GCC was at some tradeshow and gone all last week.
I suspect that I'll be in the middle of the 2 companies each blaming the other but if anyone has had and successfully solved this issue, I could use some ammo.
(Cross-posted on Sawmill Creek and Engravers, etc forums)