Running a train (Athearn PA-1 with dumny A pulling a 7uni t Athearn consist )when all of a sudden the overload light came on and the circuit breaker popped.No derailment so it was strange .Waited a bit until the circuit breaker popped back on and no out put at the variable track voltage Tried the direction and momentum switches but no result .I got out my multi testor and moved the throttle dial but still got zero.I tried the fixed voltage which is supposed to be 12 volts but it was putting out 22 volts.Tge fixed A)/C was reading 16 so it does not look good.I took the sheet metal cover off but all wires are connected .I am not tech savvy so I am stumped .Afraid it is only good for powering lights or switches!Any hope?
I've had my share of QC issues with the three C-M 20s I've had over the years. Two had to go back for repairs and in several cases the remote quit working (I had spares of those).
I still have one of the repaired C-M 20s still working on my layout I use for auxiliary power for building lighting. The variable DC still works fine. I really can't say what the problem can be in yours. The rectifier seems OK since you get straight DC out of it. Possibly it could be the overcurrent protector itself. You can get resetable circuit breakers from some of the electronics suppliers and try replacing the auto-reset one?
https://a.co/d/eQbh0HH
[edit] I was mistaking the type of MRC model you have. Mine are the larger Control Master 20s that used the wired remote.
Maybe you can pick something up from this?
Good Luck, Ed
Thanks for the help!Luckily I have a second Control Master ll that I bought in 1986 that still works fine but looks bad because I left it too close to the area that I paint so it has lots of overspray on it. . not pretty but works just fine!
I found some info at:
http://www.sumidacrossing.org/LayoutElectricity/ModelTrainPower/PowerPackTesting/
No internal pictures, unfortunately. Your readings are about the same on the fixed voltage. My guess would be a power transistor is bad. Per that article, look for a TAT wiring diagram and see if that is similar.
Are you testing disconnected from the layout?
Gary
Yes ;thanks for the info!
I found this video. Not well lit, different power supply, but you can see the transistor: