The ALS1300 and 600 has had some issues with the 12 volt sections of the switching supply.
This is nearly all of the field problems in the 1300. Once transistors are changed with replacement parts, those that do fail seem to stay OK. There have been a few revisions of the 12 volt supplies, and I think the final revision of the 12 volt module should be a keeper. It has been a real tough problem to catch, because they don't fail often enough to actually see it happen.
I think the 12V problem in the ALS600/1300 Power Supplies is more prevalent than you might believe. I had mine fail 3 times before Ameritron finally swapped out the PS with one that has the improved 12V modules. With yourself and W7AIT, that's 3 of us just on this forum thread. I've had a couple of people email me also noting issues with their power supplies.
As to Ameritron notifying people of possible problems with the Power Supply 12V sections, I haven't seen anything posted by them. More the "If it breaks, we will fix it" approach to a possible design problem
By the way, my power supply was swapped out in mid December and the ALS-1300 has been running great since then.