I recently updated this F3 set to PS2 5V using the innards from another set. It has the main board in the lead A unit and a slave board in the trailing unit, 10 pin pass-thru cable in the empty B unit. All was well, it was running fine for a couple of days. Lights worked fine, markers, couplers etc. The last time it ran it shutdown normally and was left on the track overnight
Next morning on startup, it would not move. Seemed like the trailing A unit was locked up. Took the trailing A off the track, opened it up, and found the board was quite warm to the touch. The smoke unit was also very hot, even though smoke had been turned off all the while it was running. Put it back on the track, unattached to the lead. As soon as it was powered up it shot ahead uncontrolled. Meanwhile the lead A and the B unit behave normally. They startup on command and run just fine on their own.
The trailing A unit acts like the board is scrambled for some reason. No idea how or why this might have happened. The night before it ran perfectly.
Anyone any ideas what might have happened and what can be done? I am at a loss, first time I have seen this kind of thing happen. 
Thanks, Rod
