Legacy CP 10 Wheeler Barely Responds to Forward/Rev Commands

It may be the motherboard; I'm dealing with a NOS Atlas RS-1 right now that does everything - except move in reverse. In mine, the radio board is fine; the motherboard is not. No mechanical problems.

Not the same issue exactly, but it rang a bell. I'm going back to it this afternoon.

Actually, come to think of it, why have you (apparently) not e-mailed Lionel tech support? They answer. 

Thanks. Mine runs in both directions...just not controlled well with the SO3 original board. And does not run at all with the SO1 board. The question now first is, are there differences in the R4LC boards which could prevent running the motors at all with the SO1 board? Something to do with the Legacy code over TMCC code? I assume the SO3 board is faulty somehow disallowing absolute command control on running. 

I figured Lionel is out for the weekend.

I had the same issue with a legacy diesel. turn the momentum to L (low) on your 990 remote.

make sure your engine is off.

Hope this helps.

Michael.

Not sure how the momentum affects the engine taking off by itself. Did your diesel do this too?

Hi Chuck,

 If I'm understanding the issue you're having correctly, to me the issue is with the speed control which is attached to the motor in this engine. Did you check and make sure  the flywheel isn't loose and hitting the speed sensor. It also might be a defective sensor board.

 

mine did not have sudden acceleration. it only moved slow and did not respond to throttle response. this was an earlier legacy diesel. once I changes the momentum to low from med, everything worked fine.

Alex, yes that's all snug. What's odd is how it doesn't run at all with the C01 board and takes off slow and rambling to faster irratically with the C03 board.

If I try an R2LC C08 board, it does exactly the same as the R4LC C01 board...won't move at all, but all other functions, programming, sounds, etc. all work. I keep wanting to try a new R4LC C03 board...just holding back from ordering until Monday since nobody is going to mail it before then at Lionel...and I might learn different here.

This engine is from about 2010 or so.

Hi Chuck

This issue does sound  quite odd , I'm interested to see if the a new R4LC does the trick. Please keep us posted. 

Thanks,

Alex 

I'm surprised that nobody mentioned an obvious suspect, one that I've replaced a few times.  The things that control the speed in this locomotive are the sensor board on the motor that Alex posted and the DCDS pictured below.  I seriously doubt that your R4LC is at fault here.

Thanks John. What about when I tried the new R4LC C01 board that I happened to have on the shelf and the self starting rambling down the track stopped? That made me think that the original R4LC C03 was at fault. The odd part to me is that with the C01 board, although the rambling down the track stopped, the engine would not move at all. But all else, sounds, etc. worked.

Do you know if a C01 board should have worked in all respects and should replace a C03 board?

There has to be a reason that the firmware is different, but I don't know what changed.  Do you have another Legacy locomotive of a similar vintage that you could test that C03 board in?  The most common failure I've encountered when I have no speed control is the DCDS.

Question:  Is the symptom that you crack the throttle and the locomotive accelerates independent of the throttle setting and continues to run at full speed?

If the motor encoder is bad, the engine will normally start to take off, but stop after a few feet when it senses the lack of tach pulses.  That can also happen if the DCDS is bad, depending on where the failure is.

No. When you turn on the 18vac track voltage, the engine starts to move in a jerky manner and goes faster and faster. Spinning the throttle on the CAB2 CCW tends to slow it down, but not very well. Pressing the reverse does not work except once in about 10 pushes and the engine reverses and runs backwards just as it did forwards. Basically uncontrolled. All the sounds work, no blinking headlight. I have continuity from the boiler rails to the C1 on the R4LC card as to the antenna.

When I substitute the R4LC C01 or as well an R2LC C08 card they both result in the engine seeming to be controlled, but the throttle does not make the engine move. All other functions, sound, etc. appear to work.

Well, the C01 board doesn't run it at all, and from the sound of it, the C03 is the only one that makes anything as far as motion happen.  Truthfully, it might be the R4LC, but my money is still on the DCDS from that description.  The encoder normally either works or doesn't work, and the fact that reverse isn't recognized has nothing to do with the motor decoder.  I still think finding a R4LC-C03 in another locomotive and testing your suspect one is a good first step.  Why buy something that you may not need, might as well buy the part you do need first.  The fact that all other functions work on the R4LC also suggests to me that it's strictly a motion control issue, that's the DCDS.

Well...First I kept calling the board C03 when it was actually S03 for the R4LC board originally in the engine. And the one I had in stock that kept the engine from taking off by it self is an R4LC S08-S01 board. And I am pretty convinced that the S08-S01 board is different enough not to run this legacy engine throttle wise.

I was checking out the signals on the R4LC S03 board (Rigol scope, eh?) while the engine was running by itself and it appears that the forward and reverse lines out of the board were low mostly with an occasional high pulse or two. Plus there was a lot of noise on +5 and some on other pins. I was using the ground on the heat sink to refer the scope to. Checking the continuity of the ground pins to the outside rail, I got a lot of intermittent resistance. So I suspected a ground issue on the board or engine to be the source of all the problems.

BUT WHILE I WAS CHECKING THINGS...the engine started functioning properly. With the S03 board. Before it fixed itself I tried the S08-S01 board and it still didn't allow me to run the engine with the throttle and the signals out of the forward and reverse pins were high...and the engine did not fault to running by itself. So the ground issue seems to have been on the R4LC S03 board and not in the engine. The mother board seems not to have been the issue since I have had the boards on and off a dozen times without any change in how it behaved with either board. I cannot find any solder joints on the board that look suspicious...no hair line cracks around the pins, etc. The fact that the forward and reverse pins with the S08-S01 board stayed high and the engine never faulted ever with it (even though it would not run with the throttle) makes me pretty sure that the S03 board has, or rather had, the ground issue.

I think the best thing to do here is return the engine to service (belongs to one of the train running friends in our somewhat informal club...I seem to be the guy they say "could you look at this". I say "no time", but I do it anyway and work free trying to avoid starting a new career), and order an R4LC S03 board for stock.

Thanks to all for your patience in reading this, hope it adds to the knowledge base, and thanks for all the comments.

Happiness is a solid bug.  Too bad this isn't happiness!