Ulrich
I think this is worth reporting as well.
We took out assy all the way to 200V but no RUN , we had correct VDD & HVG, REF. THESE COME UP FROM AROUND 18v or so.
We did notice quite a bit of random transitions during the drop in HVG waveform but nothing else.
In order to explore why RUN would not go up, I soldered a stub at Q5 gate.
Lo & behold, the controller died when we applied VBULK & VDD & sws had the marks of the failure we have reported so much so far.
Cannot report by measurement, but it suddenly occurred to me that it is not ESD at the solder tip but surely AC leakage. Any amount directly going to any pin, you are history.
If this is so, it will explain easily why we have seen several mysterious failures.We surely were not paying attention to the sequence of events following soldering- in proto 3, there was ISO7710F failure on the high side & that mystery was at the back of my mind all these days.
Most likely, the leakage of ac is random & of random amplitude. If I devise a test, I will try to measure it.
We ordered new soldering stations. We get them tomorrow- only then we replace with a new controller.
-robin
