I think you maybe have a mistake, if Main Chip has problem, the ONT even can't start and set in web.
[12/3/2015 16:23:29] Michael Wei: I discussed with the tech.
Please try follow way.
[12/3/2015 16:24:11] Michael Wei: check the OLT parameter setting.
[12/3/2015 16:24:48] Michael Wei: use one OK ONT and one Problem ONT, compare their parameter same or not.