Hello! First time posting, hopefully this is the right place. I recently got an MTH Alco PA A/B set off Ebay and it seems to be working wonderfully expect one thing...When running togther, the A-unit will accelerate slower and deaccelerate slower than the B-Unit. They seem to be going the same speed once they accelerate or deaccelerate, but they just don't match up slowing down or speeding up.I've tried resetting the CV's with the locomotive with CV 29 and CV 55, but nothing seems to work. All the CV's for Speed control seem to be the same on both units, but the momentum on the A-Unit will not match the B-Unit no matter what I do. They also seem to be locked at a Speed step of 17 out of 28, and I cannot get it to go any faster than that. (I have an ESU CabControl DCC System, and the remote itself will stop rotating at 17 speed step.I want them running together in a consist, and I'm still new to this, so I really need some help.Thank you!
MacKaeAll the CV's for Speed control seem to be the same on both units
Remember that MTH only does DCC by accommodation, and from what I have read, in a piss-poor fashion. Especially if you're using 'legacy' speed steps rather than more modern 127 or 128 or whatever functional steps, this might be a decoder issue... and my unsolicited opinion is that you just take the MTH decoders out and replace them with better ones if you have no reason -- as I would have no reason -- to run DCS.
Not familiar with MTH decoders, but normally CV 3 is starting momentum and CV 4 is stopping momentum. You would increase the amount of CV 3 to make that engine ramp up to speed more slowly, or reduce CV 3 to make an engine get up to speed more quickly.
Two engines of the same make and model by the same manufacturer normally are not 100% identical in their running characteristics, so you need to adjust the CVs on each separately to get them to start, run, and stop together like one unit.
Both diesels must have the same speed tables set, and CV2 for V-Start adjusted individually so that each gets underway barely with a single speed step set on the throttle, CV3 for 'inertia', and CV4 for 'momentum'. They would also need CV5 Top-End Speed and CV6 Mid-range Speed set the same. Assuming the decoders and their firmware/software are the same, and that their slaved drive mechanisms are the same (not from separate runs set years apart, for example), I don't see any other impediment to their working well together except for some other mechanical defect, bad/missing lubes, that kind of thing.
MacKaeI've tried resetting the CV's with the locomotive with CV 29 and CV 55, but nothing seems to work.
My understanding is the CV55 reset only resets the address, not the other concfigurations, and CV29 is not a reset. Try programming CV8 to 8, that should do a factory reset.
MacKaeThey also seem to be locked at a Speed step of 17 out of 28, and I cannot get it to go any faster than that. (I have an ESU CabControl DCC System, and the remote itself will stop rotating at 17 speed step.
If you're controller stops at 17, then that's a setting somewhere on the controller, not the locomotive.
I've tried going through everything and resetting it. Now the engines accelerate and decelerate at the same pace until about speed step 11 out of 28. (No longer stuck at a max of 17, so it turns out it was a decoder issue) Once it goes to 11 or higher the B unit goes faster than the A unit.
I don't think I've tried CV8 to 8, but I will try that next.
Here's a video I made showing my issue:
https://youtu.be/Pr8-tbQ1T_8
MacKaeNo longer stuck at a max of 17, so it turns out it was a decoder issue
I don't know what you did different, but if the controller was not going past 17, it wasn't a decoder issue. The decoder doesn't have any control over what the controller does.
However the controller can be smart enough to react to what the decoder does and doesn't allow. It's not really what's important though.
I also did the CV 8 to 8, and it's still the same as you can see in the linked video.
I think it's the A unit that might have the issue, as once it reaches about speed step 11, I don't notice any increase in site speed on speed steps past that. I've tried making sure the CVs for low, middle, and high voltages are factory default... not sure what else to do.