I have a SW7. Lionel 6-85024. The couplers front and rear stopped working. The sound still comes out of the speaker. I pulled the cab off and checked the couplers on the bench and they open at around 6 volts. I then checked the board out put and it showing around 5.5 volts. Put it back together and neither still do not open. What am I missing here?
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You've tried resetting?
Are you speaking of a master reset or reset on the controller? I have on the controller but not a master
I’m referring to resetting by reprogramming the engine ID.
Yes sir I have tried that also. Changed the number and didn’t change anything. I wasn’t sure how many volts are to come off the RMC board. I know on the bench it takes under 6 for the coupler to open and very quite. Didn’t go past 6 volts on the bench. But the board is only pushing 5.5 volts off the board. Wasn’t sure if that’s where the issue might be and if there’s anyway to turn that higher?
Just out of curiosity are you measuring AC or DC volts off the PCB and are you measuring with the coil plugged in or no load?
I am measuring AC without it plugged in and with no load. With a load would that not measure less?
Well anyone with more experience can correct me if I’m wrong but I believe the RCMC puts out DC voltage to the couplers not AC. And I would definitely measure the voltage with the load in the circuit. Without the load you may read some “capacitive” voltage that when the load is there disappears and what could be going on is that I think the RCMC uses FETs for the couplers and they might’ve failed where you may see some voltage but can’t handle the current and then the voltage goes away.
That’s my first thought. Weather or not my theory is correct or not I don’t know but that’s where I would start
Yes, the RCMC outputs DC to fire the couplers. And yes, you need some kind of load on the coupler output to measure the voltage. Also note that you'll only get about 1/4 second of voltage when the coupler fires, so if you don't have a 'scope it may be hard to actually measure it.
Thanks for answers. I will tear it back down tonight and measure it dc with a load. So the question still remains, what should it be putting out? And if it is low, what can be replaced short of installing a new $120 complete board. When I talked to Lionel yesterday they couldn’t answer that question. There response was to take all the boards out, reassemble everything and make sure all connections are tight going back together. They didn’t think there was an issue with the boards other than something was not making a good connection.
I have never measured one to see what it puts out, and as I pointed out, I suspect you'd need a 'scope to see the pulse anyway.
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