Hi Charles, Thank you very much for your reply. Yes, the short is between pin 2 & pin3 of J_SUB. We think we didn't do anything wrong according to the user guider. We've bought all of the main chips on the board. But before we change new chips onto the board, we should find the cause of the damage. Our power sequence was : GND,VSUB(-50V),3.3V,1.8V,+5V,-5V,+10V,-10V,+50V,-50V. 1. Does +50V and -50V need to be powered on simultaneously? 2. Does -50V need to be powered on before +50V? 3. Is any possiblity that the Power Jitter damage the chips when +50V is powerd on? But 3.3V and -5V are short to GND, that's weird. We are stuck by this problem and can not move on. Really need for TI's advice. Yours sincerely, Frank
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