Peck,
I have not seen a schematic for the design and therefore cannot speak with authority, but shouldn't a proper design take a failed motor into account? Driver chips typically have high-temp shutdown feature, and I would think a proper design would add in short-circuit sensing and protection.
To me, a proper design would separate the main control electronics from the driver board, particularly if the driver components are the most prone to going belly up when something bad eventually happens. As I mentioned before, though, I would think the driver board should handle a bad motor gracefully, shut it down, and warn the user (even with something as simple as a blinking LED on the same board). A proper design would also reduce the cost associated with losing a particular component... if you can cut replacement costs in half by splitting the motherboard into two pieces (at little extra cost), it's a worthwhile investment. $1,300 to receive a refurb'd board is pretty steep (I can't imagine what a new board costs), particularly when it's something that should have been a $200 driver board (and that $200 has a LOT of profit cushion built in). A proper design takes maintenance into account, not just proper operation.
When things go <pfzzt>, it means two things... a protection component itself has gone bad (like losing a driver chip due to failed over-temp protection circuit), or the circuit was not properly protected in the first place. Since I can't see the circuit, I cannot make that kind of determination, but I think any reasonable person would agree with the two possibilities mentioned before being the only valid ones.
Components do go bad, I've been the victim of many in my own designs, so here's to hoping a driver chip just went belly up.
Agreed Dan. Let's remember that this is all based on speculation from the information we've been told.
There's no factual data telling us that the rotary motor was shorted; caused the rotary drive chip to blow, bypassing any safety features built into the MB of Pat's machine; possibly causing other components to fry.
One of Pat's questions was if others have seen such problem. I can honestly say yes, others have probably seen "similar" failures like in Kim's case. When you look at the big picture, thousands of Mini/Helix's sold with an overall very minimal failure rate (I'd guess a small fraction of 1%) then my statement regarding our electrical engineering capacity holds water.
The creek is a great place with great members but what I beleive most tend to forget is that members of such great forums are a small community/percentage of overall laser owners so when one says it's a bad design/common problem; overall, does it make it a true statement?
I can't comment on whether our design is the best possible one available and that every single electrical component is bullet proof to the 5th degree. I can only assure Epilog owners and prospects that we do our very best to provide the best quality laser engraving system in the industry.
So where does this leave Pat? To save money, he'll have to do some trouble-shooting, possibly some parts locating and attempt to repair the board himself.
If unrepairable, I'm still offering to see what our service department can do to limit the costs. If the time involved is a factor (big jobs, orders due, etc.) then as a business owner, he'll have to decide whether the cost of a replacement board is worth the jobs and revenue lost from the down time.
Another thing to consider is that there's no guarantee that he can repair or have the board repaired locally w/out coming across other issues (no one has seen the board but himself). There's also no guarantee that our tech support group can repair his board.
There's just no easy answer/solution here.