TheRailwire
General Discussion => N and Z Scales => Topic started by: TVRR on November 15, 2020, 04:00:15 PM
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HI, I have a second run loco that has developed an issue that I do not know how to diagnose- motor vs DCC chip. While running at a moderate speed it suddenly stopped, all sound continued as if the loco was still in motion. I cut power and the motor restarted, ran maybe 5 min., and stopped. I have reset the decoder several times and restored original CVs without any effect. As soon as power is reapplied sound starts and continues at the same rate and volume as the instant the motor stopped. I strongly suspect the DCC chip but how do I tell for sure? I liked this loco's performance and wonder if replacement decoders are still available?
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I assume you have already inspected the connector from the engine where it plugs into the tender? It is easy to pull on the wires when disconnecting the engine from the tender, which can lead to poor connections.
I think you can run it with the tender shell off, which should make it easier to find the culprit when the symptoms occur.
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Wires and connections are OK to visual inspection. Just on a whim I took the tender loose and removed the loco. When power was applied the tender went through the start up cycle then immediately reverted to the previous sound pattern. This would seem to indicate that the problem is in the decoder to me. Almost everything else I have is ESU lok sound or Digitrax.
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Just to be clear, is this the Life-Like/Walthers Mallet loco with the factory installed QSI Revolution decoder?
Which DCC system are you using?
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Yes this is a second run loco with the QSI system from the factory. I'm using a Digitrax DC50 & a DC 51 and have been for 12 years. The system has worked perfectly with this loco for years and continues to do so with everything else I own.
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Yes this is a second run loco with the QSI system from the factory. I'm using a Digitrax DC50 & a DC 51 and have been for 12 years. The system has worked perfectly with this loco for years and continues to do so with everything else I own.
Not trying to blame the DCC system - I just wanted to know what it is for troubleshooting purposes.
Just to clarify "sound pattern", do you mean it is chuffing as if it was running at some speed (not stopped)?
What was the reset procedure you used? QSI decoders do not use CV8 for resetting the decoder.
After a decoder reset, did it revert to short address 03?
Can you control any functions using that address? Like headlights, or bell, or whistle?
Can you read back any CV values on the programming track?
Here is the reset procedure I found at https://dccwiki.com/Decoder_reset (https://dccwiki.com/Decoder_reset)
QSI also has a user software reset using the following multi step procedure:
Place engine on main track if it is still responding to its address. If not responding you may need to use the program track.
Set CV49 to 128
Set CV50 to 255
Set CV56 to 113
As the decoder in the engine resets you will hear an audible response, the horn may sound three times, or it may talk to you. Test the locomotive using address 3.
You can then go ahead and set the loco number as you desire and/or reprogram other CV’s.
An irritating issue with QSI decoders is when they do get corrupted by a short, the locomotive can exhibit very erratic operation. Resetting it back to default will put you back in control of its performance.
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I have pretty much the same issue with mine. It's a second run but I had the decoder installed by a pro shop. Soundtraxx Tsunami 2. I ran great but then suddenly decided to stall and hardly get out of it's own way. Then it doesn't want to move anymore and the sound works as if it's moving when power is applied. Also as soon as I put it on the track the sound comes on. There no longer is a start up, hummm.
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QSI Revolution and Soundtraxx Tsunami decoders are like a apples and oranges. The only thing they have in common is that they are sound decoders. I'm really surprised if some problem causes them both to behave same way.
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Thank you for the useful tutorial Peteski. The sound starts immediately @ 4chuffs/sec. and continues without change no matter the throttle setting. You can silence it with f8. Yes I reset it to 3 with no issues, reads back correctly when changed to 5 also. I attempted to reset with your procedure on the program track, CVS 49 and 50 reset without issue but CV 56 will not read or write, nr appears in the display. Yes I can control bell, whistle sound functions and the lights without problems. Your thoughts?
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If you can control the decoder on whatever address you have it programmed to (you can control bell, whistle, and the lights) then try the reset procedure by doing the same reset procedure but writing to the CVs on the main track. Just make sure that the throttle is set to whatever the address the decoder is responding to.
Set CV49 to 128
Set CV50 to 255
Set CV56 to 113
After the last step do you hear any audiable response?
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No audible response detected. Decoder will not program CV 56 on mainline with OPS programing either.
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I lost track of the motor behavior after the initial description of the problem. Is it still the case that if you cut power and wait a little bit, you can turn it back on and the motor will run for a few minutes before it quits again? Or is the motor not running at all now?
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Hi Mike, The lack of motor function is full time now. It restarted after it's first motor shutdown ,no response since. When attempting to reset, CV 56 will not read or accept changes on either the main in OPS or the program track.
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No audible response detected. Decoder will not program CV 56 on mainline with OPS programing either.
Since in OPS mode you can only write CVs (no readback), do you really know that the decoder is not accepting write to CV 56? Or are you hearing the value of the other 2 CVs spoken in human voice as you are programming in OPS mode (but when you write CV 56 there is no announcement)?
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Placing it back on the Prog track and attempting to read CV 56 still shows "nr", so I'm making the assumption it did not take. BTW, it reads every other CV I've checked.
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Assuming that the decoder is still addressable (you can control sound functions) and it is emitting sounds, in the OPS model write value of lets' say 29 to CV 64. I human voice should speak the CV number (29) and its value (whatever CV29 is set to). In the OPS mode, writing a value to CV64 will have the decoder speak the value of that CV.
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Hi Mike, The lack of motor function is full time now. It restarted after it's first motor shutdown ,no response since. When attempting to reset, CV 56 will not read or accept changes on either the main in OPS or the program track.
I would suggest disconnecting the motor leads, hooking the motor up to some plain DC to see that it runs. Make sure the motor itself doesn't have a problem. I know you're seeing some weird behavior with setting the CV's too, but maybe the motor shorted, shut down the decoder, and was the root cause of this. It would be important to at least know the motor is okay.
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Peteski, I changed CV 64 to 9 and got a voice confirmation in OPS mode. Attempt to write to CV 56 gives a "busy" response. Max, I'm afraid that taking the loco apart enough to check the motor leads is beyond my level of competence and confidence.
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Peteski, I changed CV 64 to 9 and got a voice confirmation in OPS mode. Attempt to write to CV 56 gives a "busy" response. Mike, I'm afraid that taking the loco apart enough to check the motor leads is beyond my level of competence and confidence.
Hi (and it's Max, by the way... no problem)...
Have you gotten in to where the decoder is? You could also disconnect the motor at that end and put power to the leads. Or does this strictly have to be an "outside the engine, don't take anything apart" kind of diagnosis?
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Max, All the goodies are in the tender so I think I can get it open (ha!). How would I identify the motor leads? The less disassembly required the better, since having my cataracts removed I am leery of small stuff.
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Well, the standard says that the orange and gray wires from the decoder should be the motor leads. But looking at photos of the inside of the 2-8-8-2 tender on the Spookshow website, it's all done with nice neat DCC plug/socket, so all the wires are black. You could unplug the decoder, and then if you could figure out which two wires on the plug go to the motor, you could hook power to those.
However, the boiler shell should just lift off after removing a couple of screws. I think it would be a easier to lift the boiler off and disconnect at the motor itself. Once you disconnect the motor leads, you'd be safe to touch some leads directly to the motor to see if it runs okay.
I'm not trying to beat a dead horse about this. It just seems to me that in addition to checking all sorts of possibilities with a decoder, it's important to back up a minute and make sure the fundamentals of the engine actually work. Even if you decide to replace the decoder, it really would be best to make sure everthing works before putting another decoder in there.
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Sounds like a plan, I'll try it and see what happens.
Later this PM Looked at Spookshow's invaluable site and was delighted to see that one screw under the cab and one in the smokestack are all that holds the body on. I had visions of taking apart a body like the Kat Mikes as I did a few years back, in pieces. In the morning when I've got good light and coffee I will try this. Thanks again guys.
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Here is the tender of that loco. But it has a new wire harness I built after the original one melted (I was fixing that loco for someone). I used the correct color codes for my harness (not all black). :) But as you can see, there is no good way to tap inot the motor leads. The connectors are very small.
(https://www.therailwire.net/forum/gallery/2/2700-301017184451-2801718.jpeg)
Maybe inserting pieces of solid wire into the connector unplugged from the decoder, then attaching some alligator clips? But one has to be careful not to spread out the female connector contacts.
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Thanks, Peteski! Excellent photo. (And very neat wiring on that repair!)
That's what I thought when I saw the Spookshow photos. It just seems to me that the motor is pretty accessible on top once you get the boiler off, and it should be possible to disconnect the wires from it and test it.
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In looking at your rewiring job it appears that the motor leads occupy the outer L & R positions of the tender plug. If so, can I apply power through the corresponding engine plug slots via the conveniently located bare strips on the bottom of the connector? With little probes?
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In looking at your rewiring job it appears that the motor leads occupy the outer L & R positions of the tender plug. If so, can I apply power through the corresponding engine plug slots via the conveniently located bare strips on the bottom of the connector? With little probes?
No, not outer. Those are rail pickups (red and black) Motor connections are 2nd in from each side (orange and gray). Yes, if you have some probles small enough to make contact, that should do the trick.
The tender connector pintout is as follows:
RED - right (+) rail pickup
ORANGE - right (+) motor lead
BLUE - common positve for the headligth
WHITE - F0F headlight negative lead
GRAY - left (-) motor connection
BLACK - left (-) rail pickup
Thanks Max! :D
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Meanwhile back at the ranch, I found some 0.010 bronze phosphor wire and made tiny probes. The motor does run smoothly as ever (whew). BTW the 0.010 wire fits neatly into the engine plug. Since this is now apparently a decoder issue, are replacement decoders available anywhere? Are there reset possibilities we have not looked at yet? I really appreciate ya'll helping.
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Meanwhile back at the ranch, I found some 0.010 bronze phosphor wire and made tiny probes. The motor does run smoothly as ever (whew). BTW the 0.010 wire fits neatly into the engine plug.
Since this is now apparently a decoder issue, are replacement decoders available anywhere? Are there reset possibilities we have not looked at yet? I really appreciate ya'll helping.
That's a tough one. Yes, it sure seems like the decoder has lost its "brains". These decoders were specifically made for that model (although I think it was also used in some Walthers H0 switcher). QSI Solutions is also not really selling decoders. Well, there is still QSI. There were 2 parts of the company - I don't remember the details, and one part is still in business. But that decoder board was custom-made for Walthers. Of course Walthers sold all their N scale (ex Life-Like) locos to Atlas. You could contact Customer Service/Repair at Walthers and at Atlas t see if they still have some leftover decoder boards.
I'll PM you some Walthers info, and maybe @EmdFan would have some info about parts availability for this loco from Atlas side.
If all else fails, and you want it, I could take a look at it. I have fixed one of those decoders for a TRW member few years ago. But that was a hardware failure (burned out transistor). Yours might not be as easy to fix. I have the QSI Quantum Programmer (used for uploading sound files to those decoders), but not sure if that will help here.
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QSI decoders get "stupid" after a long period of non use. There is a way to reset them. Essentially they read, but don't do anything else. I do not have enough experience with QSI decoders to guide through this one, but this link seems to be helpful: https://tonystrains.com/news/how-to-rescue-a-faulty-decoder/#:~:text=QSI%20Decoders&text=Some%20use%20a%20magnetic%20%E2%80%9Cwand,of%20the%20whistle%2Fhorn).
If any of this has been stated already, my bad for posting duplicate information.
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Glad your motor is good.
So now I am puzzled. Is it really critical to put that exact same decoder in there as a replacement? Couldn't you just put in any sound decoder that will fit? After all, if this decoder isn't really available anymore, why not just bite the bullet and get a new one that is still supported?
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Max I was thinking that I liked what I had and would buy another if I could. I have ESU loksound in 9 locos and like it too. Meanwhile I just out to cussedness tried to reload CV 56 and it TOOK IT. I have no idea why this time it worked but not the previous 50. I'm going to let it run and see what happens, many thanks to you and Peteski for his generous offer.
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Well that didn't last long, 2 min and it stopped again, sound just keeps on chugging. Sigh.
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I checked and CV 56 remains set & readable @ 113. Sigh.
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In the event that this chip is just corrupted, what sound decoder would you recommend? I'd like to keep the speakers and the honking big capacitors if I could. ESU by preference.
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I really like QSI decoders and I wish they would have continued making them. They sound simulation of the steam enigne is excellent. The chuffs get louder and heaver under load, and much quieter when coasting. The chuff synchronization with the drivers is also superb. Then there is rod clang noise. It was a great decoder, ahead of its time. They still make some large scale decoders, but nothing that would comfortably fit in N scale loco.
The repeated failures might be indicating that there is a short somewhere. Maybe between the circuit board and the metal tender frame causing this odd behavior. When I serviced that Mallet few years back I noticed that some of the circuit traces on the decoder were in paces that if the solder mask was scratched off, the could contact the metal tender frame.
Maybe you could remove the screws holding down the decoder and let it sit slightly above the metal frame, then if you get it to reset again, see if it will run more reliably with the decoder away from the frame.
If you do decide to replace it with another decoder, I would be interested in buying that decoder from you.
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In the event that this chip is just corrupted, what sound decoder would you recommend? I'd like to keep the speakers and the honking big capacitors if I could. ESU by preference.
While they sure look impressive, those honking capacitors aren't really all that large (capacitance wise). You can get some polymer tantalum caps which will fit the same volume, and give you more capacitance. Also, those caps are not the typical keep-alive caps. I don't have the decoder handy, but IIRC, one of them is rated 6.3V and it is not used in the typical keep-alive sense. Also, aluminum electrolytic caps are dollar a dozen. :D
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Peteski, I'd like to take you up on your kind offer to look this thing over. It's plain that I am not going to solve this problem. Please PM me mailing instructions at your convenience and thank you again for your generous offer.
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Sure, I'll take a stab at it. The worst thing that can happen is that you will end up installing another decoder in it. PM sent.
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That's a tough one. Yes, it sure seems like the decoder has lost its "brains". These decoders were specifically made for that model (although I think it was also used in some Walthers H0 switcher). QSI Solutions is also not really selling decoders. Well, there is still QSI. There were 2 parts of the company - I don't remember the details, and one part is still in business. But that decoder board was custom-made for Walthers. Of course Walthers sold all their N scale (ex Life-Like) locos to Atlas. You could contact Customer Service/Repair at Walthers and at Atlas t see if they still have some leftover decoder boards.
I'll PM you some Walthers info, and maybe @EmdFan would have some info about parts availability for this loco from Atlas side.
If all else fails, and you want it, I could take a look at it. I have fixed one of those decoders for a TRW member few years ago. But that was a hardware failure (burned out transistor). Yours might not be as easy to fix. I have the QSI Quantum Programmer (used for uploading sound files to those decoders), but not sure if that will help here.
We did acquire the 2-8-8-2 and will eventually run it, and update the decoder obviously. But to be honest it may take some time. We did not get any parts in the deal, just a few samples.
Steve W
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We did acquire the 2-8-8-2 and will eventually run it, and update the decoder obviously. But to be honest it may take some time. We did not get any parts in the deal, just a few samples.
Steve W
Thanks for the info Steve. While not immediately helpful in this problem, it is still helpful to know that Atlas does own the tooling for this loco and plans to eventually produce another run of these models. And we now also know that Atlas has no spare parts.
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That is wonderful news Steve! It is a great loco and I can see a 3rd one in my future.
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Well good holiday news, my 2-8-8-2 is back from Peteski and it works just great. At this point I have no idea what he did, but he did it well. Many thanks friend!
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Well good holiday news, my 2-8-8-2 is back from Peteski and it works just great. At this point I have no idea what he did, but he did it well. Many thanks friend!
That was good timing! I mailed the package (2-Day) Priority Mail back on December 11 and it looks like it arrived just in time for Christmas! Merry Christmas TVRR!
Looking at the tracking info, the package took some time to get into your neighborhood, then it was further delayed. Looks like you had some nasty weather in your neck of the woods!
Delivery Exception, Local Weather Delay
*******, TN 378**
We were unable to attempt delivery of your item on December 24, 2020 at 4:50 pm in ********, TN 378** due to hazardous or unsafe weather conditions. Your item will go out for delivery on the next business day as conditions permit.
I'm working on an illustrated write-up of my troubleshooting. I was an unusual problem. When ready, I'll post it here.