If you have an N Scale Model POwer 4-6-2 Pacific with a Soundtraxx Tsunami DCC sound decoder in it, please let me know the CV settings you use. The slowest this thing will run on speed step 1 out of 28 is actually pretty fast.
I don’t use 128 speed steps, but I tried it just now, and this thing would not start moving until speed step 24.
I tried setting CVs 2, 3, and 4 (Vstart, Acc and decel, respectively) to all 0 and then set CVs 209 and 210 to 0 and then adjust CV 209 upwards in OPS mode until it started moving, but it would not move, even when CV 209 (Kp) was set at 255 (same with CV210 - Ki).
Ultimately, I’m trying to get the CV116 chuff rate of 4 chuffs per driver revolution to match at speeds at which I can count them, up to about speed step 10 out of 28. I used the formula in the manual, and it was spot on at speed step 3, but off for all other speed steps.
I suppose I could adjust each speed step to match the driving chuffs, but that might result in a lot of uneven speeds and throttle increases.
Thoughts on how to get this locomotive to go slower and be able to match chuffs per driver revolution?
With all the issues you are experiencing with sound decoders in N scale, perhaps you should take a step back and allow a professional to look at it and perhaps do a reinstall of the decoder.
Just cramming a decoder and speaker into a tender does NOT mean that the loco will work as you think it will. There are steps taken before the decoder install that are critical before you even think about investing time and lots of money.
In particular, this loco has a few issues that are critical to its operation before you install a decoder. The first is the pickup scheme…the wipers on the rear of the drivers tend to misalign and bind in reverse. There is no fix for this as it is a flaw in the design from Model power. The result is a stiff mechanism that will run for a time under stress…then fail. Meter testing should be completed before installing a decoder.
Im not trying to rain on your N scale sound parade, but I have performed dozens of sound installs in N scale steam locos for my customers. In N scale there is a delicate balancing act between quality sound and reliable operation.
In N scale, electrical pickup is severly hampered by removing the weight in the tender to accomidate a sound decoder and speaker. There are only 2 steam locos on the market that have metal tender chassis to accomidate a sound decoder with no loss of weight…those are the Spectrum Bachmann J class and the Concor 2-10-2. Every other steamer uses a plastic chassis for the tender with weight added to help electrical contact.
Your particular loco is a POOR choice for sound. Even if you will be able to get it to run slower, it is only a matter of time before it fails completely…and fries your decoder with an amp spike. It has just t
Per the review in MR, April 2003, their sample had a minimum speed of about 10 smph. That’s kind of high compared to modern locos, even in N scale. It’s pretty good compared to the junk N scale stuff I had way back when.
Can’t win for losing - the Kato has a MUCH better mechanism, but worse pickups. This one has better pickup but a worse mechanism.
Facts of life. And that’s a steam loco with a realtively large tender space. Look at an N scale diesel - it’s basically a solid chunk of metal with a motor and gears buried inside. No room for speakers, barely room for decoders - there didn;t used to be room even for a motor only decoder until they started making them with a circuit board for directional lighting on DC, as long as the decoder is no bigger than the factory board, they swap out. But older loocs you needed to mill the frame, or have iot milled, to make a space for a small decoder and try to ahrd wire it in. No thanks. N scale is a departure from my concept of using a standard decoder in everything - unless your loco fleet is very restricted, not every decoder maker has a replacement decoder for every brand of N scale loco, so you need to use whichever brand makes a suitable replacement.
N scale sound - considering the biggest speaker you can possibly use is going to be 9mm or smaller, you aren’t going to get much sound out. Untertable is probably the best option for N and smaller.
Dave, thanks for the advice. I guess I should have noted that I replaced the Model Power tender on this with a Bachmann Spectrum all-wheel pickup tender. It has a metal floor, so it’s actually heavier than the old Model Power tender with the weight. It performs beautifully.
I did do a meter testing, and you assumed that I did not. That’s why I replaced the tender. The axle wiper pickup method was not satisfactory to me.
Oh, this locomotive has never been in reverse, so I’m not worried about that.
Unless this was the era of misprinting all the current draw tests, in the MR review, STALLED, it pulled only 0.09 amps. There was a period when the printed current draws were off by a factor of 10, so it might be .9 amps, which would be not good.
And looking at other reviews in the same issue - it might be misreported. Although if it’s 10x off, then the Athearn N F59PH draws 1.9 amps stalled - that doesn’t seem right. But the printed measurements for the Bachmann On30 Shay is like 5 mA. That seems ridiculously low.
It doesn’t matter what a review says. He mentioned that the loco doesn’t start until speed step …whatever…hence the question about its stall current. To me, I wouldn’t install a decoder until tests are done.
That was when the speed steps were set at 128 instead of 28. If I do it at 28 speed steps, it start’s rather fast at speed step 1, close to 8-10 Smph. No amount of changing CVs 209 or 210 could change that.
Hence, why don’t care for Soundtraxx decoders. Given a choice between sound and good, low-speed motor control, I’ll take low-speed motor control hands down everytime.
So, I must have missed it, Jim. You weren’t able to install the Loksound decoder you purchased earlier? Also, why do you prefer 28 speed steps to the finer control of 128 speed steps?
I’ve always had a Soundtraxx decoder in this engine. The LokSound was planned for the Kato Mikado, but I could just not reliably get that thing to work (worked very well with the Digitrax decoder I had but I changed it because I wanted sound in that thing). Yes I’ve heard of good motor control with Loksound decoder, however, when it won’t work in the engine you’ve put it in, then something’s wrong.
I gave the Loksound to my friend and put it into his Model Power N scale Pacific, and it ran beautifully. No hiccups, stalls or anything like that. The starting speed was still a bit high, maybe 6-7smph, on speed step 1 with the Loksound.
I just never really liked the 128 speed steps. Just a personal preference I suppose.
I’m still debating over whether I want to try my hand at Loksound again for my N scale 2-8-8-4 EM-1, or if I want to do Soundtraxx. Or possibly even try TCS Wow sound decoders.
Getting back to the subject, I think what I’m going to do is to set each speed step individually according to chuff rate. Unfortunately, there’s no way to set the chuff rate for each speed step.
[D)] That’s right, Jim. Thanks for straightening that out.
That is surprising that that Loksound decoder had a starting speed that high. I have three and they have all had a starting speed of <1 sMPH. The WOWSound decoders may be worth a try. Not sure right offhand if TCS makes any small enough to fit in a N-scale steamer though.
Well that’s right on with the review sample 10 years ago - just under 10smph starting speed. It should do a little better with PWM and BEMF, the tests in MR are all with pure filtered DC. Doubt anything you can do outside of major replacements will make this a tie to tie creeper.
So I’ve decided to match the speed to the chuffs. This is what I did for anyone else who has an N scale Model Power 4-6-2 Pacific with Tsunami.
I set the chuff rate, CV 116, to 115 to match with speed step 1. Then I enabled the speed tables using CV 25 and CV 29. I set CV 25 to 16, and CV 29 to 50 (this also enables 28 speed steps, and enables function 0). Then I individually set CV 67 through 94. This is what I set them as:
CV67 (speed step 1): 2 (would not start moving any slower than that)
CV68: 7
CV69: 12
CV70: 17
CV71: 22
CV72: 28
CV73: 33
CV74: 39
CV75: 44
CV76: 50
CV77: 55
CV78: 61
CV79: 66
CV80: 72
CV81: 79
I then left all the other CVs (CVs 82 through 94) alone and at the default values. I would never run the Pacific this fast anyways because 1. I cannot count that fast for the chuff rate, and 2. Those speeds seem highly unrealistic (to me at least).
The bad news is 2-fold. Firstly, once your locomotive breaks in, the motor efficiency will change and your chuffs will be off. Secondly, as your DCC system voltage changes (bringing it to a friends house or or variability with the DCC system), the chuffs will be off again.
Thanks for the advice David. I plan on using this Pacific mostly at my house using the NCE PowerCab that I have. I actually have never used this thing on another DCC system, yet.
The locomotive is already broken in, so I’m not worried about that either.
This is the best way to get the chuffs to match with the speeds that it will see, as the equation that Soundtraxx uses to determine the chuff rate worked for speed step 2 and 3, but anything faster it was off.