After a hot day of running trains with my MRC 6200, the trains stopped suddenly. A quick check revealed no power going to the track. There was power to the accessory terminals, however. It was hot and the end of the day, so I decided to let it cool down overnight and check it out the next morning.
Overnight didn't fix anything, so I opened up the pack. A quick glance at the tangle of wires was daunting. But I looked at the transformer first and noticed two glass tubes connecting between one side of both the track connections and the accessory connections. One was clear, the other blackened. The clear one was to the AC. I made a jumper around the blackened one. Power returned to the track connection. These are thermal circuit breakers which should reset after they cool down.
I checked on the internet to find replacements for the original Sylvania breakers. Not surprisingly, I couldn't find any, so decided to replace them with re-settable breakers. I found some 3 amp NTE breakers. I bought two to replace them both, figuring if one was bad, the other wasn't far behind!
I had to drill two holes in the case. I located them above the terminal strip. Using progressively larger drills, I made the holes as large as I could, but needed a ream to get them up to the needed size.
Then I soldered wires to the breakers before installing them in the pack. Finally, I wired them into where the original breakers had been. Afterward, I tested both breakers by shorting them out. Both worked fine, and now the pack is back in business, powering the Red Mountain Loop. I ran it yesterday (August 2, 2016) for about five hours with no problems.