The SE-40 I repaired a few years ago had had several rectifiers replaced, so evidently there was an issue, and I seem to remember in the information I gathered from the GTA Web group, which admittedly was little better than folklore in quality, that rectifier ratings weren't adequate.
The unloaded heater voltage isn't relevant. You should measure it fully loaded.
The unloaded heater voltage isn't relevant. You should measure it fully loaded.