# I might have killed my MTH Steam Engine - Speed & Sound Issue



## CO-Mike (Dec 12, 2020)

I have a MTH O Steam Engine PS2 (3v) I might have killed. Currently I have no sound, and the engine will continue to accelerate uncontrolably when you scroll the speed control to 1 scale mph. I can stop the engine by simply scrolling back down to 0. Lighting, coupler, and smoke operates as it should. Strange happenings when trying to retrieve odometer readings. Will skip between actual reading and 0. Not sure if anyone has experienced anything like this or has any repair advice (other than good luck on trying to buy a replacement control board...)

Background and the woes of my ways... So I dove head first into an upgrade from a previous post, adding a 3rd center rail pickup to a 2-8-0 engine that could not make it through a large turnout (2 tender pickups only 3 1/2" apart). I had previously built my own battery component replacement with the guidence of a particularly knowledgeable member (GunrunnerJohn), but I used a 2 pin connector that was somewhat generic and was not really a "directional plug". (Relevent in a moment) Upon completing the 3rd pickup installation with an in line PPTC fuse, I tested all connections to make sure there was no posibility of a short. Last step, re-connect the super capacitor pack and test it out. Carelessly I had reversed polarity on the super capacitor pack (wires hidden beneath factory zip tie - yes dumb move not checking closely). As soon as I put power to the track I noticed some strange feedback in the speaker and quickly turned everything off. Imediately found the reversed super cap pack, fliped the plug and attempted to power the engine up again. Not this go-round... 

I have since checked every connector, tested continuity from engine to tender on every wire across the wireless draw bar, and between each component and the board. All good, cleaned, and checked the tach sensor gap. Speaker reads 4 ohms when tested. I have completed several factory resets of the engine, and also downloaded and re-installed the PS2 file from the MTH website. 

Thats the history, and my sob story... Any thoughts, suggestions, pointers, other than pay closer attention ding-dong..... ?


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## CTValleyRR (Jul 26, 2014)

Sorry... no help from me, but our moderator, Gunrunnerjohn, is an MTH tech and runs MTH O gauge himself. He might have some ideas.


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## gunrunnerjohn (Nov 10, 2010)

Hard to say what happened, the runaway sounds like the tach reader and wiring or the op-amp on the power supply board (top board of the PS/2 3V board stack). The sound is somewhat if a mystery, that usually happens if the speaker leads get shorted to the frame, takes out the audio amp. Those are fun to replace, they're very small pitch SMT parts!

I suspect the way to start here is to get the board set tested and sort out any issues with that first. Next is to make SURE that there are NO GROUNDED OR CROSSED wires coming and going to the PS/2 board set. The electronics does not take kindly to any kind of chassis short, everything is isolated from the frame except the track power inputs on the 7-pin connector. Once the board set is proven good, if you still have the runaway, it's probably the tach sensor or it's wiring. Check the spacing and also the continuity of the wiring from the sensor all the way back to the 7-pin connector on the PS/2 board. The tach sensor connects to the first three pins, the track power uses the other four pins, sometimes only two of them are wired.


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## CO-Mike (Dec 12, 2020)

Well, I tested every connection again, and checked for any possible shorts, none found and no change in the system. Removed all of my modifications, no change, and have adjusted the tach sensor position numerous times without any change to the runaway engine syndrome. Is there a good way to test the tach sensor with a multimeter?

I guess my next step is to test the boards with known working components? Build myself a testing station? (Any pointers?) I found the TPA2000D1PW, definitely looks like a good time to replace that.. and found an EE-SYS124 but might be an obsolete component, is this the best / recomended component if I have to replace the tach?


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## gunrunnerjohn (Nov 10, 2010)

Building"a test set for PS/2 will be a lot of work, I got mine the easy way from MTH when I went to the school, at the time they were $175. You also have to make complete cable sets to connect the boards. There's lots of manual labor and time involved. Unless you're getting into the service business, that's probably not very practical!

One way to test the board is to drop it into a similar locomotive. No easy way to test tach sensors with a meter, you'd really have to power it and then check the sensor output. I normally just stick another one in. Of course, since I first put the board set on the test-set, I would already know if there was any board issues before I start chasing phantoms in the wiring/sensors.

The sensor on the tach board is an obsolete component, you will probably not find it available at most parts houses.


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## CO-Mike (Dec 12, 2020)

Thanks again John! Thats a bummer these sensors are obsolete, I'll keep searching around to see if anyone has them or something comperable I can use to fabricate a new tach sensor board. 

I do like the thought of having a board to test engines, especially since I am messing around with them so much. Maybe if I get bored some day I can wire something up with harneses for PS2 and PS3 cables using any components that are interchangable. I suppose I'll leave that discussion for a different day, since I really don't know what all the spec differences are between components yet...


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## gunrunnerjohn (Nov 10, 2010)

CO-Mike said:


> Thanks again John! Thats a bummer these sensors are obsolete, I'll keep searching around to see if anyone has them or something comperable I can use to fabricate a new tach sensor board.


It would actually be pretty easy to substitute a different sensor and lay out a new board, that's my plan if I ever get to where I can't get sensor boards.


CO-Mike said:


> I do like the thought of having a board to test engines, especially since I am messing around with them so much. Maybe if I get bored some day I can wire something up with harneses for PS2 and PS3 cables using any components that are interchangable. I suppose I'll leave that discussion for a different day, since I really don't know what all the spec differences are between components yet...


Forget about trying to make a PS2 & PS3 combined tester, they're as different as night and day! Everything about the boards and interfaces is basically different! The one exception is the PS32 board that is used to replaced failed PS/2 boards and is also used in the PS/3 steam upgrade. That's a PS/3 board but it has a stacker board to convert it's interfaces to match PS/2 signals. I actually work on those using the PS/2 test-set. However, any native PS/3 board will require a real PS/3 test-set.

The PS/3 test set is a totally different animal and works for all scales, it comes with about 20 wiring harnesses of various kinds for the HO/S/O/Std Gauge boards. It has about 20 test connectors around the edge, tons of switches to set options, and a 40 page manual of operations!

In order to test many PS/3 boards, you also have to have a "golden" board set as stuff like PS/3 steam has two boards, one in the boiler and one in the tender. You need to be able to test one and have a known good board connected to the other side. That's where the "golden" boards come into play. I have well over $500 invested in this setup, and I only use it for O-gauge stuff, I have resisted working on HO.


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## CO-Mike (Dec 12, 2020)

Wow, that test board is pretty impressive. I suppose I have to think real hard about investing in something like that, considering it is for PS3 only (If it is even available anymore.) I, like you would only use it for O Gauge trains, and most likely only for personal use. Its not even the right shape to use as a hat rack in between uses... I'm sure it would come in handy though. Thanks for sharing the photo and the thoughts!


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## gunrunnerjohn (Nov 10, 2010)

Yep, and test sets were only sold to ASC's when they have been factory trained, that's when I bought both of these. However, I've seen several change hands over the years. I'd like another set of cables for my PS/2 one, MTH was going to sell those, but it never happened.


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## Zachmodeltrains (10 mo ago)

CO-Mike said:


> I have a MTH O Steam Engine PS2 (3v) I might have killed. Currently I have no sound, and the engine will continue to accelerate uncontrolably when you scroll the speed control to 1 scale mph. I can stop the engine by simply scrolling back down to 0. Lighting, coupler, and smoke operates as it should. Strange happenings when trying to retrieve odometer readings. Will skip between actual reading and 0. Not sure if anyone has experienced anything like this or has any repair advice (other than good luck on trying to buy a replacement control board...)
> 
> Background and the woes of my ways... So I dove head first into an upgrade from a previous post, adding a 3rd center rail pickup to a 2-8-0 engine that could not make it through a large turnout (2 tender pickups only 3 1/2" apart). I had previously built my own battery component replacement with the guidence of a particularly knowledgeable member (GunrunnerJohn), but I used a 2 pin connector that was somewhat generic and was not really a "directional plug". (Relevent in a moment) Upon completing the 3rd pickup installation with an in line PPTC fuse, I tested all connections to make sure there was no posibility of a short. Last step, re-connect the super capacitor pack and test it out. Carelessly I had reversed polarity on the super capacitor pack (wires hidden beneath factory zip tie - yes dumb move not checking closely). As soon as I put power to the track I noticed some strange feedback in the speaker and quickly turned everything off. Imediately found the reversed super cap pack, fliped the plug and attempted to power the engine up again. Not this go-round...
> 
> ...


I’m having the same problem I have a mth dash-9 diesel ho scale and It will have sounds at first then I run it then the sounds stop then I turn off my digitrax remote turn it back on the some sounds come on then it stops


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## Hamilton (9 mo ago)

gunrunnerjohn said:


> Yep, and test sets were only sold to ASC's when they have been factory trained, that's when I bought both of these. However, I've seen several change hands over the years. I'd like another set of cables for my PS/2 one, MTH was going to sell those, but it never happened.



Hello, John

This is Hamilton, I am a o gauge modeller from China. 
(Sorry for my poor English, you may find lots grammar mistakes in my words, I’ve been graduate from school for over 10 years.)

I’ve got a MTH European engine, a French 141p (20-3487-2 | MTH ELECTRIC TRAINS), and it got an speed control problem pretty much as the same.

When I turn the throttle, the engine speeds up rapidly and reaching max speed in very short time.

The light functions are fine, but the sound wasn’t, I still got most of the sound like whistles and background sound, but not “chuffing” sound when the engine starts accelerating.

There is no smoke function.

Most of my locos are European models with ESU decoder so I am really unfamiliar with MTH Proto sound 3.0 system.

I wonder if you could help me with this engine please.

Regards
Hamilton


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## gunrunnerjohn (Nov 10, 2010)

Well, I can certainly tell you where to look. Your issue is a classic sign of a problem with the tach reader or wiring between the tach reader and the boiler board in the locomotive. Start with a physical inspection of the tach reader to see if there are any broken wires, or the board is loose in the holder on the motor.


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## 2cool (25 d ago)

Hello
My name is casey and I have a question about MTH 30-1444-1 steam engine.
It has the ps2 board 3v. When I turn on my smoke unit and run the train, the engine will speed up and down on its own and then the smoke unit will quit working. Once the engine slow back down to the speed that I set it at, the smoke will start working again. Any help would be greatly appreciated.


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## 2cool (25 d ago)

Forgot to tell you. With the smoke unit off the train runs fine. This only happens when the smoke unit is on.


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## 2cool (25 d ago)

2cool said:


> Hello
> My name is casey and I have a question about MTH 30-1444-1 steam engine.
> It has the ps2 board 3v. When I turn on my smoke unit and run the train, the engine will speed up and down on its own and then the smoke unit will quit working. Once the engine slow back down to the speed that I set it at, the smoke will start working again. Any help would be greatly appreciated.


Also, i did unplug the blower motor and the heater elements and it still does the samething


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## CO-Mike (Dec 12, 2020)

You'll hear from some more seasoned members, but just a place to start... Have you reflashed the sound / control file to the engine?


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## 2cool (25 d ago)

No ideal on how to do that


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## gunrunnerjohn (Nov 10, 2010)

This is a pretty simple locomotive inside, I'd first check for any pinched wiring that could be causing the issue in the locomotive. If all of that looks good, Mike probably has the right idea. The sound file is available on the MTH site: MTH Railking Royal Hudson, you load it with the DCS Consumer Loader Program - Version 5.0.


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## 2cool (25 d ago)

This is a dum question but, how do you load the sound file into the train. Is there something special you need to tranfer the file. I don't have the remote control
Thanks


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## gunrunnerjohn (Nov 10, 2010)

2cool said:


> This is a dum question but, how do you load the sound file into the train. Is there something special you need to tranfer the file. I don't have the remote control
> Thanks


You do need the DCS system and a WIndows PC to load sound files. You're significantly limited if you just run conventional as to what fixes you can apply.


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## 2cool (25 d ago)

Thanks for all of the input. As of now, I will just leave it alone. Everything works, I just won't use the smoke. Its werd that when you turn on the smoke unit, the engine speeds up and slows down on it owns. Thanks


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## gunrunnerjohn (Nov 10, 2010)

2cool said:


> Its werd that when you turn on the smoke unit, the engine speeds up and slows down on it own.


Not that weird, that's not that uncommon an issue, typically it's something like a bad ground or the PV line has a poor connection. It can also be the smoke fan motor, if it draws excessive current, it whacks the +5V line and all sorts of odd behavior can result.


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## 2cool (25 d ago)

ok but, i did unhook the smoke fan and the smoke heater and still had the same problem with it speeding up and slowing down but, not for sure if I had both unpluged at the same time. Now that you mention that about the smoke fan, I did notice when I had the top off the engine I notice that the fan would not spin like it should. Sometimes it does and sometimes it won't. I'm going to unplug the smoke fan again and see whats happens. I will let you know.


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## 2cool (25 d ago)

What do you mean PV line (Battery line)


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## gunrunnerjohn (Nov 10, 2010)

2cool said:


> What do you mean PV line (Battery line)


PV is the unregulated positive voltage from the Board.


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## TJSmith (Nov 16, 2015)

*Try to find one of the Lionel test sets along with the documentation. I know of one set that might be avalible.*


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## 2cool (25 d ago)

TJSmith said:


> * Try to find one of the Lionel test sets along with the documentation. I know of one set that might be avalible.*





gunrunnerjohn said:


> PV is the unregulated positive voltage from the Board.


 I unpluged the smoke unit and heater unit. It still did the same thing.


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## gunrunnerjohn (Nov 10, 2010)

Well, it's likely the wiring or the board. This is one of those things that is MUCH easier to diagnose when you have the proper test equipment.


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## 2cool (25 d ago)

I agree, something in the tender went bad. This all started when the battery went bad. I had to turn the power onto the track for 15 minutes before I good even get it to move in foward. I did replace it with a BCR-2. Like I said, everything works until you turn on the smoke and the issue is with the speed. I check the wiring on the engine and everything looks good. A friend of mine is a retired electronic guy, I will have him check out the board. Thanks


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## 2cool (25 d ago)

How do you tell the difference between the ps2 and ps3 board


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## 2cool (25 d ago)

The owner manual states ps2 but mth web site show ps3 unless the ps3 was an upgrade from the ps2


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## 2cool (25 d ago)

I have the MTH 30-1444-1 (4-6-4) steam engine


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## gunrunnerjohn (Nov 10, 2010)

2cool said:


> I have the MTH 30-1444-1 (4-6-4) steam engine


From 2007, it's clearly a PS/2 engine.

 MTH 30-1444-1 4-6-4 Imperial Royal Hudson Steam Engine w/Proto-Sound 2.0


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## 2cool (25 d ago)

Does anyone know what this component is. Also, what are the specs. Its the one with the blue ring around it


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## gunrunnerjohn (Nov 10, 2010)

Well, it's a shielded inductor, I'm guessing 470uh would be the value based on the markings. Why the question about that component? FWIW, I have a couple of the power boards for the 3V PS/2 stuff still in stock.


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## 2cool (25 d ago)

I had it tested and I was told it was bad. Do you have photos of the power boards that you have. I might be interested in them.


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## 2cool (25 d ago)

I also was told that, this is a battery capacitor. I really don't know 
John if you don't mind could you call me. 
Thanks Casey 1-660-853-1900


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## 2cool (25 d ago)

Are you still around


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## gunrunnerjohn (Nov 10, 2010)

Yep, I'm still around. I have no idea who told you that this inductor was a battery capacitor, whatever that is. I would recommend you stop taking electronic advice from that person as he clearly has no idea what he's looking at!

This







is clearly a shielded inductor, the 470 indicates the value I suspect, probably 470uh. Given the fact that the person you mentioned has no idea what the component is, I doubt I'd take his word for it that it's bad. 😲 

My take at this point is to start eliminating possibilities, my first step is usually testing the PS/2 board separately from the engine and eliminating that as a failure. Then you move on to the wiring, tach reader, smoke unit, etc.


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## 2cool (25 d ago)

I might be interested in those boards that you have. Are they new of used. How much do you want for them


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## 2cool (25 d ago)

If you look real close there are 2 wires that stick out on each side. Is it a possibility that, it is a coil choke. That is what digikey told me


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## gunrunnerjohn (Nov 10, 2010)

2cool said:


> I might be interested in those boards that you have. Are they new of used. How much do you want for them


There aren't any "new" PS/2 boards available, they haven't been produced since around 2010.


2cool said:


> If you look real close there are 2 wires that stick out on each side. Is it a possibility that, it is a coil choke. That is what digikey told me


Yes, it's an inductor, aka _choke_. I dug out my inductance meter, it's a 58uH inductor, don't know what the 470 stands for, most likely a part designation. I decided it was too small to be 470uH, that's why I measured it. FWIW, it's actually pretty unlikely that part is bad.

Maybe you should start by why you suspect that part or even the power board of the PS/2 board set. Shotgunning a repair by randomly replacing parts can get expensive.


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## 2cool (25 d ago)

ok how much for the boards that you have. are they new


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## gunrunnerjohn (Nov 10, 2010)

2cool said:


> ok how much for the boards that you have. are they new


Did you read my previous post? There are no new PS/2 boards. I'm a MTH ASC, I repair boards if possible. Normally, I keep them together as a set for 3V boards, but I have several extra repaired PS/2 power supply boards that I don't have matching processor boards for. However, I'm still wondering how you know it's the power supply board you need?


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## 2cool (25 d ago)

ok now I have no control over the speed. It has a mind of its own. I'm guessing that its the speed controller chip. if so, do you have a part #


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## 2cool (25 d ago)

Is there anyway that you would call me. Here is my number 1-660-853-1900 Casey


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## 2cool (25 d ago)

Lets start over. I only use the train for christmas. I put it around the tree. It all started when I went to turn it on, It would not go into forward or reverse unless I charged the battery for about 15 minutes and then it would work until you let it sit there awhile. Had to charge it everything before I could run it. After reading some blogs, I decided that I would replace the battery pack. That fixed the issue. Then one day I went to turn on the smoke unit and the train speed up and slow down on its own. I did unplug the smoke unit and the fan and still did the same thing. I did clean off the tac unit and flywheel but, continue doing the same thing. This is why I wanted to have the boards look at. I was assuming that was the issue. Now I'm back to the tac board. I assume that it controls the RPM'S. I did check all of the connectors and grounds and found no issues. Now, it has a mind of its own. It pretty much does what it wants now on speed. Not much control on the transformer.
Is it a good chance the the tac board went bad.
Thanks Casey


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## 2cool (25 d ago)

FHD0026.MOV


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## gunrunnerjohn (Nov 10, 2010)

It could be the tach reader and/or tape, the wiring between the engine and tender, or the PS/2 board stack. There is an op-amp on the PS/2 boards that sometimes gets toasted..


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## 2cool (25 d ago)

Is that op-amp available


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## gunrunnerjohn (Nov 10, 2010)

As long as you don't need more than 30,000 of them.

TI LMV358M/NOPB


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## 2cool (25 d ago)

Stupid question. Is this a chip that needs to be programmed?


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## gunrunnerjohn (Nov 10, 2010)

Nope, it's just a dual opamp.


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## 2cool (25 d ago)

I ordered a new tac board. I will let you know if that fixed it. Also, is the tac tape just a black vinyl or is it magnetic
Once again thanks for you help on this matter


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## gunrunnerjohn (Nov 10, 2010)

The tach tape is just paper, I print my own as needed.


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## 2cool (25 d ago)

Hey, I just wanted to say thanks for all of your help. I got it fixed. I found a broken orange wire in the pig tail that goes to the tac reader I temporary by passed the tac reader orange wire from the steam engine to the tender and it ran great. Everything is working now. I will get a new pig tail. 
Thanks Again


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## gunrunnerjohn (Nov 10, 2010)

Glad it was an easy fix.


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## 2cool (25 d ago)

thanks again
Casey


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## 2cool (25 d ago)

2cool said:


> thanks again
> Casey


Got the new pigtail on it today, and all is good. Thanks again for all your help.


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