Legacy J class doesn't run right

Same old question, what is the Lionel Product Number?

@gunrunnerjohn posted:

Same old question, what is the Lionel Product Number?

1931340

Check the connection of the antenna to the handrails and also make sure the handrails aren't grounded to the shell.  For the runaway and error, I'd be looking for a loose flywheel or perhaps a broken wire from the encoder to the RCMC board.

@gunrunnerjohn posted:

Check the connection of the antenna to the handrails and also make sure the handrails aren't grounded to the shell.  For the runaway and error, I'd be looking for a loose flywheel or perhaps a broken wire from the encoder to the RCMC board.

I’ll look into those, thanks! What made me think it was a motor board was because I had a CSA challenger that did the exact same thing and it was a motor board problem. I’ll report my findings soon

Well, that sounds like the encoder isn't being recognized.  I always look for the cheap causes before shelling out $150 for an RCMC.

@gunrunnerjohn posted:

Well, that sounds like the encoder isn't being recognized.  I always look for the cheap causes before shelling out $150 for an RCMC.

I completely understand you there! Do you think that would be the issue if there aren’t any loose wires or other cheap fixes?

In that case, my next step would be to test the board, I happen to have a testset for just that purpose.

@gunrunnerjohn posted:

In that case, my next step would be to test the board, I happen to have a testset for just that purpose.

Woah, that’s super cool! Well, since I don’t have one of those nifty custom tools, what method would be best to test the board?

Well, I don't really have any good ideas, that's why I made my RCMC tester!  However, I'd first exhaust all the things you can do with physical inspection, good chance you won't have to figure out how to test the board.

I looked it over, and I think it all looks okay. Do you see anything I’m not?

Is that a disconnected wire in 1st pic?

@tom21pa posted:

Is that a disconnected wire in 1st pic?

It does not appear to be, no. I have pulled on it and it does not move. The handrail antennae’s are connected on the front of the engine above the scale coupler, so it makes me think that wire does something else.. but what?

@Sams Trains posted:

It does not appear to be, no. I have pulled on it and it does not move. The handrail antennae’s are connected on the front of the engine above the scale coupler, so it makes me think that wire does something else.. but what?

Some thing looks off here, like the left side has a wire but not the right and it looks like there was something connected there to me at least.  Not saying there was

@tom21pa posted:

Some thing looks off here, like the left side has a wire but not the right and it looks like there was something connected there to me at least.  Not saying there was

It does look like that, but all the connections have wires going to them, so I’m not sure

@Sams Trains posted:

It does look like that, but all the connections have wires going to them, so I’m not sure

I am pretty sure the things I boxed in red are supposed to be connected

It's pretty likely these two wires were connected, they sure look like the antenna connection.

Note that the location of those two feed-thru's are right where the antenna terminates on the J.

I'll bet money if you check continuity between the two antennas, you will not get a reading.  Also, if you follow those two wires back to the RCMC, they'll both go to the TMCC receiver board connection.

@gunrunnerjohn posted:

It's pretty likely these two wires were connected, they sure look like the antenna connection.

Note that the location of those two feed-thru's are right where the antenna terminates on the J.

I'll bet money if you check continuity between the two antennas, you will not get a reading.  Also, if you follow those two wires back to the RCMC, they'll both go to the TMCC receiver board connection.

I think John nailed it.  The other issue is if that bare end is touching the shell it's shorting out the signal all together.

@MartyE posted:

I think John nailed it.  The other issue is if that bare end is touching the shell it's shorting out the signal all together.

And on an RCMC, if it did short, it’s usually the death knell for it,……they’re not hardy like an old TMCC radio board, ….I’ve zapped more than a few R2’s & R4’s in my time, and did not kill them,…..RCMC’s and LCP2’s have a weak constitution IMO, …..😁

Pat

OOPS! Stupidity wins again! I had accidentally traced the wire connected to the shell to a different point, when in fact it was the other antenna wire as we all speculated. I did not get it unstuck from the shell (it snapped at the heat shrink) but with the antenna no longer grounded to the shell, EVERYTHING works perfectly! Legacy connects, and there's no more motor issues. Thanks @gunrunnerjohn and everyone else for your help! Now to see if I can unstick the piece of metal stuck to the shell

@gunrunnerjohn posted:

Check the connection of the antenna to the handrails and also make sure the handrails aren't grounded to the shell.  For the runaway and error, I'd be looking for a loose flywheel or perhaps a broken wire from the encoder to the RCMC board.

Funny thing, one of my early posts to the thread.

@gunrunnerjohn posted:

Funny thing, one of my early posts to the thread.

Well, I had done just that, except I traced the second wire from the receiver board to going somewhere inside the cab, and the wire that was supposed to be the antenna connection to some other plug on the RCMC thinking it was a ground. A second look this morning changed that thought

@harmonyards posted:

And on an RCMC, if it did short, it’s usually the death knell for it,……they’re not hardy like an old TMCC radio board, ….I’ve zapped more than a few R2’s & R4’s in my time, and did not kill them,…..RCMC’s and LCP2’s have a weak constitution IMO, …..😁

Pat

The Antenna input to the RCMC is capacitor coupled, so shorting the antenna wire to the shell won't damage the RCMC receiver.

I've never had an antenna shorting to the frame damage anything for the  R2LC/R4LC or the RCMC.  Pretty much any other wire from the RCMC shorting to ground is very bad however.

Small update: With the shell off, the engine runs fine, but when I put the shell back on it goes back to not receiving legacy, and having the same motor issue. Maybe I need new antenna wires completely?

Check the insulation from the handrails to the shell, most likely at least one handrail is shorted to the shell.  When you put the shell back on, it's nicely screwed to the frame and grounds the antenna.

@gunrunnerjohn posted:

Check the insulation from the handrails to the shell, most likely at least one handrail is shorted to the shell.  When you put the shell back on, it's nicely screwed to the frame and grounds the antenna.

I think I found the one, although it is still being finicky. That, and now when I try to move it the engine takes off again, then stalls and the cab light flashes

@Sams Trains posted:

I think I found the one, although it is still being finicky. That, and now when I try to move it the engine takes off again, then stalls and the cab light flashes

That's usually problem with the encoder rotation being sensed.  Obviously, that can be the encoder, the flywheel position, the toothed wheel coming loose from the flywheel, the wiring, or the RCMC.

@gunrunnerjohn posted:

That's usually problem with the encoder rotation being sensed.  Obviously, that can be the encoder, the flywheel position, the toothed wheel coming loose from the flywheel, the wiring, or the RCMC.

Yayy, what problems! Looks like I’ll have more digging to do. Are you taking commissions on RCMC testing? I’ll send you this one if you are

Testing is cheap, send it along.

I can attest, John's test fixture is great!

Sam, while you still have your model apart you may want to also check the blue tooth board as I have had to replace a RCMC in this exact model due to a feedback from the BT board.