Reminds me of a similar situation. We were working on a device powered by what looked like a 6 pack of 16 Oz cans caps charged to 500V. SCRs controlled the discharge of the capacitors into the device and caps were charged in opposite polarity so that the device could deliver current in opposite polarity depending on which way the mechanism was to move. There was a flaw in the logic that controlled the SCRs and in some circumstances both directions were on resulting in a direct short between the two banks of caps, discharging all stored energy in a fraction of a second (about 300 ms IIRC) That resulted in catastrophic failure of the SCR which propelled pieces of casing across the room and left my ears ringing.<p>I asked that a cardboard box blast shield be placed over the H&#x2F;W before participating in further tests.