Wow, second one that does that. What the heck is up with these Tsunami decoders that Bachmann is using?
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Well well, at least I don't feel like the Lone Ranger. (That's an expression we old guys use.) I thought I might be getting senile.If my measurement are correct top speed is 29.6 scale MPH and there is no increase after step #19. Also we thought removing the resister that's across the motor output leads of the decoder might help. No such luck. The lack of a constant speed increase is what made me think there was something wrong with the decoder.If I can't find a way to get the engine apart for cleaning without chipping the paint I'll run it as is.I do like the look of the engine.
You all have a good day.
Lee
Well if the drive is gummed up then we should be seeing lots of motors frying if for 1/3 of the throttle range there's an increase in power supplied to the motor but it can't turn any faster. Should be easy enough to check and see if the motor gets hot after a minute or two at full throttle.
davidmbedard It isnt the decoder, but rather the drive that is gummed up. The Tsunami isnt looking for motor revolutions for it's chuff, but rather the voltage going to the motor. If you have a situation where the gearing is gummed up (absolutely the case here), then the motor is working very hard, the decoder harder and the result is was the OP has outlined. The only way around this is to remove the gunk from the gears. This is not an easy process, but if you want to free up the loco, it is the only way. David B
It isnt the decoder, but rather the drive that is gummed up. The Tsunami isnt looking for motor revolutions for it's chuff, but rather the voltage going to the motor. If you have a situation where the gearing is gummed up (absolutely the case here), then the motor is working very hard, the decoder harder and the result is was the OP has outlined.
The only way around this is to remove the gunk from the gears. This is not an easy process, but if you want to free up the loco, it is the only way.
David B
David is absolutely right about the electronics aspect of this, both the slow top speed and the chuff problem may be the result of increased amp draw that is not resulting in additional revolutions in the motor.
And he is correct that sometimes Bachmann has been known to over lube a a gear tower or two or even 10,000.
BUT, I have had three earlier production 2-6-6-2's apart and none where over lubed and all three I have had apart, and two others I have tested, all run fine on DC with a top speed of 50 smph at 13.5 volts which is the highest track voltage my system has. And the recent speed tests I did to try to help Lee where done with my train room at only 50 degrees - surely if gear lube was a problem with my locos they would have been slow under those conditions.
So in my mind this problem still remains somewhat of a mystery. Simply a decoder programing issue? - that I can't answer, I don't personally use DCC and have not known anyone personally to have this problem, with this or any other loco, to get their opinion/outcome.
A combination of decoder and gear lube? could well be, there is nothing to say this latest run of locos in not over lubed untill someone takes a few apart.
I'm still waiting/suggesting that someone having his problem unplug their decoder, insert the jumpers and run the loco on DC - still run slow? - than OK its the gear lube, but if it runs 45-55 smph on DC, than Bachmann has a decoder issue with a batch of these.
About disassembly - getting the dome off is the tricky part, it is pretty tight most of the time. After that its pretty easy to do, just involved because all the wiring must be disconnected and removed from its "routing" though loops cast into the boiler weight. Then it must all be carefully reinstalled.
Someone/anyone - if you have one of these and are having this problem - did the loco come with DC jumpers like the non sound/DCC only models do? If so unplug your decoder, install the jumpers per the little instruction paper and try the loco on DC - this may well provide the answer for many.
Sheldon
If it didn't come with the jumper, since the decoder plugs in to an 8 pin socket on the loco you can use the 8-pin dummy plug from most any other loco to convert it to DC only.
ATLANTIC CENTRALI'm still waiting/suggesting that someone having his problem unplug their decoder, insert the jumpers and run the loco on DC - still run slow? - than OK its the gear lube, but if it runs 45-55 smph on DC, than Bachmann has a decoder issue with a batch of these.
Hi I don't have access to DC or the jumpers but I have disabled the BEMF. The factory suggest using 16 or higher for acceleration and deceleration but all this does is make it jump going down grade. I ask Bachmann for a little help to determine if I needed to send the loco back and was kind of ignored. Oh well, it looks good.
yankee flyerI don't have access to DC or the jumpers but I have disabled the BEMF...
yankee flyer...The factory suggest using 16 or higher for acceleration and deceleration but all this does is make it jump going down grade...
Lee, I understand your position, and that you are relatively new to the hobby. We are trying very hard to help here. I also understand your interest in and commitment to DCC.
But I will suggest, that if you expect to progress in your ability to resolve problems in this hobby and/or advance to building/kit bashing or installing your own decoders, that you invest in a basic DC power pack.
Having the ability to test locos without decoders before you install decoders or being able to test motors directly with no electronics in the picture is basic in this hobby, even in these days of high tech DCC. The DCC guys have a saying, if it runs good on DC, it will run good on DCC, if it runs bad on DC, it will run bad on DCC.
Dispite the "desires" and complaints of many new people in this hobby, this hobby is not likley to ever be completely "plug and play" friendly and is always liklely to require some "basic skills" of modeling, electronics, mechanics and construction for the fullest satisfaction for the modeler. I suspect many of "collector/runner" types who are not interested in the "modeling skills" aspect of the hobby will not stay in the hobby long term and their "collections" will become just that - collections on a shelf, not a working layout.
In fact, that's what many of us like - the challenge of actually doing it ourselves, not just buying a bunch of stuff and playing with it.
Just like you, I find it frustrating when products don't perform as expected. And, since DCC came on the scene I have had a number of such problems because products where designed for DCC first and my DC system was not fully considered in those designs - so I feel your pain - in reverse.
But there is an answer to this problem - be it too much gear lube, defective decoders, or simply the need for a BETTER decoder - but again, based on the three I own and two others I have worked with for a friend, it is not the motor or the driveline of the loco - aside from the gear lube possiblity, which of course is an assembly issue, not a design issue.
CSX Robertyankee flyerI don't have access to DC or the jumpers but I have disabled the BEMF... So was there any change when you disabled Bemf? Did the loco still max out at speed step 19? Just to be clear, I'm not asking if the top speed is any faster, but whether or not it still reaches the top speed by step 19. yankee flyer...The factory suggest using 16 or higher for acceleration and deceleration but all this does is make it jump going down grade... I'm not sure what you mean about making it "jump" going downgrade, but acceleration and deceleration settings should not have any effect on how it operates on grades.
I have never been able to get the loco to respond any differently. It always max's out at around step 19 and is flat from there on. The acel. decel. Makes the throttle respond faster or slower. Slower throttle response smooths out the locos response to gravity pushing it down grade. Gravity wants to speed up the loco, decoder reduces power, loco slows too much, decoder adds power, endlessly.I've tried so many combination that i'm getting tired of looking at it.
ATLANTIC CENTRALLee, I understand your position, and that you are relatively new to the hobby. We are trying very hard to help here. I also understand your interest in and commitment to DCC.
I realize and do appreciate the help. I also like the challenge of learning new things, but sometimes budget constraints override wants and desires. I do think there is a design flaw some where in this unit. Since I have sent it back to the factory once with no real change I don't think sending it back again will improve anything. I shall ponder the dilemma some more.
yankee flyer I do think there is a design flaw some where in this unit.
If there is a design flaw, it is completely contained within that part known as the sound decoder, simply because there are likely ten thousand of these things out there already WITHOUT sound decoders and not one of those owners has reported here or on the Bachmann Forum (which I follow pretty close) any similar problem with a non sound version of this loco, DC or DCC.
Straight DC and DCC non sound versions do not seem to be effected - seems pretty clear to me. Prior to the DCC/sound version this loco has been on the market in DC and DCC versions starting in 2004.
Surely if there was some cronic flaw it would have been discovered by now and been all over these forums. Only with the appearance of the onboard sound version has this problem been reported. And, there have been some second hand reports from others on this forum about sound versions having similar problems to yours.
Having some idea of the size of a Bachmann production run, there may well be even more than the ten thousand I suggested earlier out there. Just betweem me and two other C&O modelers I know, we have over a dozen, they all run fine - BUT non of them came with sound.
yankee flyerI have never been able to get the loco to respond any differently. It always max's out at around step 19 and is flat from there on. The acel. decel. Makes the throttle respond faster or slower. Slower throttle response smooths out the locos response to gravity pushing it down grade. Gravity wants to speed up the loco, decoder reduces power, loco slows too much, decoder adds power, endlessly.I've tried so many combination that i'm getting tired of looking at it.
My DCC knowledge is more book learned than hands on, but this sounds like the motor and decoder are not properly matched - again, suggesting a different/better decoder may well fix the problem.
yankee flyerThe acel. decel. Makes the throttle respond faster or slower. Slower throttle response smooths out the locos response to gravity pushing it down grade. Gravity wants to speed up the loco, decoder reduces power, loco slows too much, decoder adds power, endlessly.
RobertI have used so many different configuration that I no longer remember clearly what did what. I have had the loco run down grade with almost no jerking. this was probably without the BEMF or momentum. I need to clear my head and not think about it for a few days and then sit down and plot the different responses.I've had the tender unplugged so many times I broke a wire and had to take the connector apart to resolder a pin. That was fun. Most of my local hobby shops aren't into DCC so they are no help. The local train club is just starting DCC.
I shall overcome!!!
Well just to further add to the confusion, it actually can make bucking on downgrades WORSE with BEMF turned on - if what's causing the bucking and surging in the first place is a sloppy drive train, the BEMF can cause it to overcompensate when things tighten up, then when they break loose the motor voltage is way too high for the current speed so it surges until the BEMF can back off. Over and over. That's apurely mechanical fix - if the work moves back and forth too much you can add thrust washers to reduce the amount of free play. This is common in diesels, too.
There really isn't any "matching" decoders to motors like trying to match amplifier outputs to speaker impedences, or antennas to radios. As long as the decoder can handle the maximum motor current, you're good - except in one special case, high precision coreless can motors. These require a decoder with high frequency PWM motor drives - so those cheap buzzy Bachmann DC On Board decoders are out - and will quickly destroy a coreless motor. That's not in play here - the Bachmann model in question does not have a coreless motor.
In the other thread are some suggested CV settings - worth a shot, and since the Tsunami is so complex it may very well be more than one CV interacting in a way that does not produce optimal results. I would do a reset and then try those suggested values and see how it runs - don't bother changing the address, leave it at 3 to test. If it works, then set the correct address. There are preset speed tables in the Tsuunami - not sure how those are actually set, you could try it with no speed table by setting CV29 to 2 for a short address or 34 for a long address instead of the 50 suggested. And set the PowerCab to 128SS instead of 28, see if that makes a difference. It's entirely possible the decoder doesn't actually work properly with 28SS.