Midas Board Power Supply

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Harold Weiss" <hweiss-at-new.rr-dot-com> 

Hi All,

I had a bit of fun recently on a show.  The show just got back to the 
states from Japan, and had their electronics and set flown air cargo.  Once 
we got sound up and running we started smelling smoke.  We tracked it down 
to the main console's power supply.  Upon opening we found that a board 
containing a pair of toroidial xfmrs similar to gate drive xfmrs had burnt 
to the point where the ferite actually was burnt partially away. The 
regulators seemed to be laid out similar to what I have seen in SSTCs and 
used a IFR140 (mosfet?) and a large stud diode for each.  The supply also 
took down the backup supply which should have taken over when the main 
supply died.  The xfmrs on the backup supply were magnet wire, and may have 
had insulation failure due to vibration.  Any other ideas on what may have 
taken it out electrically?

Luckily we found this on day one of the two day load in and were able to 
get new supplies overnighted to us.

David E Weiss