Basil posted:I've bought a couple of 5v boards and haven't had an issue, yet, but I haven't run the heck out of them either. I ensure property battery charge before running. MTH made thousands of 5v boards. I don't know what the actual fail rate is and I haven't seen any hard data on fail rate other than anecdotal stories here on the forum. As we all know, anecdotal stories provide no sound evidentiary basis to form a scientific conclusion. While certainly they provide a cautionary tale, they do not tell the whole story about the 5v board. I would imagine more than 100,000 5v boards were produced. How many have failed?
All true, but remember that techs see a lot of locomotives, and the quantity of 5V boards that are dead vs the 3V boards that are dead is telling. I am fairly certain in the ten year run of 3V boards there were a lot more of them produced than 5V boards in their roughly three year run, but I've replaced a bunch of 5V boards, and not that many 3V boards. Also, since the 3V board set is separately replaceable, many times you're only replacing half the boards or individual components.
I have a large box of dead boards, I just toss one in when I get it. It has a few 3V board pieces and about 30 or more 5V boards. That may not tell you anything, but it sure tells me something! I've actually experienced a spontaneous failure of 5V boards twice in my limited selection of 5V locomotives. The only 3V board failures I've personally had on my locomotives had in the same period were easily fixed, usually caused by shorted lighting or coupler wires taking out the associated FET.
You can draw any conclusion from that anecdotal story you like, I know what conclusion I draw from it. 
