I don't think the driver transistor is giving you problems, but, just for reference:
http://www.eevblog.com/forum/projects/looking-for-transistor-data-etd41-035/
I understand that the TCI may be influenced by intermittant safety gadgets. Something to check...
http://www.eevblog.com/forum/projects/looking-for-transistor-data-etd41-035/
I understand that the TCI may be influenced by intermittant safety gadgets. Something to check...