I decided to work on the defective truck to see if I could smooth it out so I set the locomotive up for DC operation and then clamped the frame into my bench vise so I could let it run. Not quite the same as having it running on track but oh well. After several hours of running at reasonably high speeds the problems with the truck went away. I have to conclude that I missed something when I had the gears apart. Either that or something got in there when I was reassembling the trucks.
With the truck apparently fixed I re-installed the decoder and went back to playing with the CVs. I am happy to report that I now have fairly good low speed performance. The engine revs up before the locomotive starts to move on speed step 1 (of 128) which is primarily what I was trying to correct in the first place. The locomotive is still slightly balky at speed step 1 but if I go to speed step 2 as soon as the engine starts to move it runs fairly smoothly and is still very slow. It is not perfect but I hope that some running time will loosen up the gears a bit more and eliminate the problem.
To those of you who suggested various CV settings, I ended up with the following:
I am going to leave the locomotive set up this way for now and once I get a usable track loop set up on my layout I will put it on the track and let it run for several hours and hopefully the gears will smooth out even more.
Keep in mind that AFAIK all sound decoders for diesels are set up to have the engine sound rev up as the engine starts to move. That’s just the way they’re designed. You can delay the start of the engine’s movement so the rev-up sounds start before movement, but it sometimes takes some doing. So it’s not a case that your decoder is faulty, it’s just designed that way. It may be by changing so many CVs to try to get the effect you want, you’ve inadvertently done something that negatively affects the engine’s slow speed operations.
The problem with the engine moving before the revs came up occurred before any changes were made to the CVs. The decoder was new, right out of the box and it did not perform realistically.
I now have it running pretty well the way I want except that it requires some more run time to smooth out the gears. If you are interested in the CV settings they are posted in a previous note in this thread.
What a lot of people don’t realize is that not all engines rev up before they move under all circumstances. On many engines, notch 1 does not incurr any increase in engine rpm - all it does is feed the power from the idling engine / generator to the trucks. The electricity provided by the engine at idle is sufficient to move an unloaded engine in notch 1.
If the engines are pulling a train, notch 1 is not enough to get things moving, so the throttle may be initially put into notch 3 or 4 to get things moving.
Interesting fact … when we did the recordings for the Loksound C630M, we record ten seconds of the engine in each notch. That’s when I noted that when the engine was put into notch 1, there was no change in rpm in the prime mover ! The funny part is the fact when the decoders are programmed, they purposely create an rpm increase for notch 1 because everybody “thinks” it’s supposed to !
That’s why engines have ground lights below the cab windows. If a throttle is inadvertantly left in notch 1, the prime mover may sound the same as it would in idle depending on the load. The ground lights are used as a visual indicator at night if the engines are creeping as they sound like they are idling.
99.99% of modellers have obviously never operated a diesel engine. I can tell you first hand that operating a real engine gives you an entirely different take on how our sound decoders should function. Listening to an engine trackside is totally different than sitting in the cab with your hands on the controls and knowing what happens with each change you make.
There’s a disconnect between what people think some of us are saying and what we are actually saying. No, the prime mover does not rev when a light engine is slipped to notch 1. But neither does notch 1 do anything more than stretch some of the slack from a long freight. I fnially managed to get a cab ride and even during simple switch maneuvers the engineer was opening the throttle to notch 4 or 5 briefly before backing down just to get things moving. I still say Tsunami has this all wrong, you just can;t work it like that without resorting to manual notching which is extremely cumbersome, trying to hit function keys to simulate the throttle positon while simulataneously trunign the actual throttle knob to control train speed. Loksound is one of the ones that gets this, by the use of momentum. Setting some momentum in my locos, I can simulate the light load, no RPM increase by gradually advancing the throttle. Or, with no changes, no button pressing, I can simulate the heavy load, prime mover RPM increase with little movement effect, just by turning the throttle knob faster. It effectively ties the throttle knob to the loco throttle so I can tweak it open then back down to get the train moving without a jackrabbit start, witht he prime mover revving up to take the load and the train just creeping away from a stop. I have yet to see a Tsunami do this, in the automatic notch mode.
The other thing I’ve noticed is that steam people rave about Tsunami more than diesel people - the capabilities to alter the sounds based on BEMF load sensing seem to all be there in the steam versions, but severely lacking in diesels. Almost as if the diesel versions were afterthoughts. If they can sense the light load of a downgrade and quiet the chuffs and amplify the rod clank, why can;t they use that same load sensing to adjust the diesel prime mover mased on load rather than absolute speed, since there is rarely any direct correlation between the train speed and the prime mover? That sort o
I think this is a case of “its my railroad and I will do what I want”, no offense intended. I understand the logic of the real engines not reving in response to throttle notch 1 but to my uninformed eyes and ears it didn’t just didn’t look right. I will just have to pretend that my engineer is a little heavy handed on the throttle and doesn’t bother with notch 1![swg] I’ll have to turn up the volume on the coupler clank.[(-D]
Exactly, that was my point. All sound decoders come from the factory set that way, they aren’t intended to work like you want (the engine revs up before the locomotive moves). Just wanted to be sure you understood the decoder wasn’t ‘defective’, it was just designed to work that way.
The hesitation you mentioned may be because the engine isn’t picking up power from both trucks. The Bachmann engine uses a split weight, similar to many N scale engines. It can be very tricky to balance everything and keep things the way they should be when reassembling it after isolating the motor…especially the brass wipers that pick up track power.
What is this ‘all’ you keep referring to? My Loksound and QSI decoders don;t move before the motor reves, even with stock CV settings. What the OP is referring to is the way Tsunamis do their startup on speed step 1 - in a GOOD loco it’s MOVING on step 1. What you end up with is the loco moving while it’s playign the ‘dieel engine starting’ sound, which is HUGELY annoying and most definitely incorrect behavior. That’s Tsunami default out of the box, before any tweaks. The other brands of sound decoders do NOT do this as their default behavior.
Gratned thsi can be fixed by adjusting CVs - but why is it liek this as the default? And then the use of the e-stop to do the shutdown sounds? There’s 29 functions, can’t you just use one of those liek everyone else does for their startup/shutdown? Starting a real loco is a specific process, so having to hit a function key to start up your loco isn;t out of line. That should also be tied to moving it - so if you don’t start the engine, you can’t move it. Then I guess you need a ‘cut out’ for a dead in tow unit since our models don;t coast.
So many possibilities for more prototypical operation with no more than the existing technology…
Wow, I love how my post was just disregarded by the OP. Anyways, if it were my loco, and I really wanted to have an H liner, then I would purchase an atlas H liner and put the bachmann shell on top. Install the tsunami in the atlas unit to see if the bachmann 3 pole/split frame is to blame or the decoder is. A close fried of mine has done this swap with spectacular results. Remember that the bachmann unit “wiper on the back of the wheels” scheme will accumulate gunk eventually causing your loco to run poorer and poorer as you go. Wipers are bad, very bad when it comes to a sound decoder that requires perfect electrical pickup. FYI, I am a pro decoder installer. The only sound decoder I should consider for the bachmann h liner is a loksound unit, as it deals with dirty pickups better than the tsunami does. Anyways, you will probably discount this post as well. Good day. David B
I did not disregard your post. You obviously have a great deal of knowledge about DCC. However I did choose to continue to work with the engine that I have instead of scrapping the drive unit.
Right now I have the engine running acceptably and with a little run in time I hope the very minor hesitation in notch 1 will work itself out.
By the way, the first thing I did was to do away with the frame contacts and wire the trucks directly to the decoder.
Thank you for the education regarding the potential problems with the wheel wipers. I also did not know that the motor was only three poles when I bought it or I would have passed it over. Live and learn! I won’t buy another older Bachmann.
Dave
EDIT: David, your tone bothers me. In the future, if you can’t be more polite, please restrain yourself from posting to my threads.
Tone can not be derived from Internet postings. Tone is produced by how you percieved read my posts, not how I have intended them. My solutions are spot on. I do not post when I can’t help with the question. Nor am I going to blow sunshine when it is not warranted. David B