# SD-45 can hardly move itself



## JackM (Jul 29, 2008)

Good thing I have a few other locos, my SD-45 can't make it up a 1.3% grade. By the time I've pushed and nudged it up the hill, it's too tired to go anywhere at all.

Strange. I would think it's a problem with motor CV settings (kick rate, stuff like that). But I don't want to be going in there and just changing things when I'm really clueless with those motor settings. I can get in over my head real quick.

Can anyone point me in the right direction with this problem. I gave it a nice "family" paint job three winters ago, but it's mostly just sat on a shelf since then. Sound and everything is great; it's like it can only go a hundred feet and then it overheats. (As far as I can tell the motors don't actually get hot.)

Your thoughts will be appreciated.

JackM

Yes, I've looked at what's in Greg's website. I don't recall anything like this being mentioned.


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## SD90WLMT (Feb 16, 2010)

Jack...if you feel the motors don't over heat.... what is getting Hot!!?

Did you touch the motors?

Is the battery getting Hot?

Is the battery actually still servicable .. and properly charged?

.... more input please buddy!

Dirk


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## chuck n (Jan 2, 2008)

Jack

Since I don't understand what you are talking about, I assume you are using DCC. Can you try your engine on a DC analog track and see if the problem persists? That might point to an electronic problem or a motor/ engine problem.

Chuck


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## Greg Elmassian (Jan 3, 2008)

measure the current draw on DC... many such situations are caused by faulty motor blocks, either bad motors, binding in the driveline, or something else.

The motor blocks up in the air, no load, should be about 1/2 amp or so each.

Greg


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## Dwight Ennis (Jan 2, 2008)

Is this the motor block that was advertised to "sip power?" Stirrin' it up. LOL!!


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## JackM (Jul 29, 2008)

Argh! I was hoping for a "change CV xx to twelve" solution. Looks like I'll be dismantling the engine today. I will report back asap.

JackM

Dirk - the only batteries I have are in my Tesla.


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## JackM (Jul 29, 2008)

I have made much progress in the search for an answer to the draggin SD-45. What the SD-45 was dragging was the three rear axles. Upon more disassembly than I really wanted to do, application of plain ol' DC power to the rails under the block got nothing. Power to one rail and the motor contacts on the opposite side got a proper response.

Backtracking:

I re-checked Greg E.'s website and found one of Ted Doskaris' Vignettes, about SD-45 problems. You'll find it about halfway down "Ted Doskaris Vignettes P. 4". Unfortunately I can't get the hyperlink to work for the actual address. His SD-45 information will be helpful to understand my description.

It turns out that my SD-45 is a model that pre-dates the model Ted desctibes in his vignette. Mine has no holes that allow re-soldering to be done to fix the factory's soldering. In my case, photo below, none of the contacts are soldered at the factory, nor do I see how they could be soldered at home. These contacts need to be aligned properly in order to pass current from track to motors. These depend on the three "levels" of the block to make correct contact (or any contact at all, for that matter). These levels are, top to bottom in the photo: the Top (seen below my test track), the motors and gears in the Middle, and the Bottom, which mates with the Top.










Notice, in my photo, that the can motors have small brass "hoop" tabs which must make contact with the forks in the black Top piece. Since the cans sit loose between the gears, they can easily rotate. Snapping the top onto the bottom piece at anything but a 90 degree angle can cause a fork to simply push the brass tab away instead of splitting the forks to make good contact. That seems to have been the case in my SD-45.

So the cure to my personal SD-45 is to get everything lined up perfectly and close the unit carefully. And hope.

Sidebar - I confirmed that mine was an earlier model than Ted's by removing one of the wheels. Mine has the older style of axles, which are tapered, not the "D" stubs in Ted's. Unfortuneatly, I had to pull the wheel the old fashioned way: by prying it off. I spent two hours trying to find a puller like Ted used, but neither AdvancedAutoZone nor Sears, nor Harbor Freight had a comparable puller. I did find one at Pep Boys, but it turned out that it couldn't expand wide enough to grab the SD-45 wheels. It will go back tomorrow.

I hope this helps someone someday. Thanks to Ted and Greg for making the information available that helped me solve my mystery.

JackM

And you called it Greg. The no load current on the motor block was .685 amps.


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## Greg Elmassian (Jan 3, 2008)

Yeah, like many of Aristo's ideas, clever ideas, but not well carried out.

So the idea with the "forks" engaging the motor "tabs" was that things were free to "find their neutral position"... sounds good, but since the motors have nothing to keep them from spinning except their location in the "forks", continued operation caused the connection between the forks and the tabs to worsen. Bad enough they are a mechanical connection, but they are also an electrical connection.

So eventually the power connection goes to heck.

The "fix" from Aristo was to solder them in place... well, now the electrical connection is fine, but many times when soldered in place, there was a mechanical bind since the motors can no longer "adjust" to their position.

So often you get binding, and you have to reposition the motor by pressing on it and heating the 2 connections... which is really difficult since you really need to heat both forks at the same time... unless you have 3 hands and 2 soldering irons, pretty much impossible.

Greg


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## JackM (Jul 29, 2008)

Well, back to the drawing boards.

Playin' around with the rear block did nothing at all, so I pulled out the front block for a thorough inspection and I can't find a thing wrong. Today's run around the track was just as it's always been: starts out looking promising, then top speed _sounds_ good, but soon starts to look like not such a top speed. After about 200 feet it's looking pretty pathetic, and by 300 feet it's at the end of it's run.

By this point, it just stops, starts up and advances an inch or two, then stops, starts up and advances another inch or two, ad infinitum. Pretty discouraging because this is my best unit. My paint job is very nice, my wiring inside is the neatest I've ever done. The weights I added put it at a hefty 13 pounds. It would be a real puller if it could only pull itself.

Oh yeah, we're running a QSI Titan PnP board plus Phoenix remote coupler controller with Kadee remote coupler on the front (no use working on the rear if it's just going to be a Mantle Queen). I think I tried the QSI reset, but nothing. On the off chance this could mean anything, it has some confusion about forward and reverse. Three toots of the horn as it begins to move forward. I'm inclined to worry about that once it can go any direction for more that once around the loop. And, no discernable heat on the blocks, etc.

I'm stumped, Any ideas would be welcome. Any solution would be REALLY APPRECIATED.

JackM


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## Paul Burch (Jan 2, 2008)

Jack,
Just curious. Are the connectors on the drive between the motors and the gear boxes plastic or metal? The very first SD45's were plastic. Didn't work out so well so Aristo offered free brass replacements. All production after that were brass. Greg probably knows more about it.


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## Michael Glavin (Jan 2, 2009)

Jack

Sounds suspiciously like a wiring anomaly or perhaps even a BAD decoder. 

Can you power the trucks independent of the decoder and associated ancillary wiring? 

Track power or battery power? 

Michael


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## Greg Elmassian (Jan 3, 2008)

Jack... step by step.

You stated that the rear truck was not turning at all... but you neglected to state how you fixed it.

You should get a set of rollers so you don't have to chase it.

The behavior you are now describing sounds like the polyswitches tripping. If the loco is pulling itself with only one motor block, then that might be too much current through those polyswitches.

So back to basics:

1. did one truck indeed stop turning, if so what did you do to fix it and have you verified that this problem is gone.

Let's go step by step... not jump ahead yet.

Greg


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## SD90WLMT (Feb 16, 2010)

Another important consideration might be worth checking while this is all going on..
Ensure all wheels turn in the same direction... on both power blocks....if they don't .. a large load will be the result!
Usually in this case.. all wheels turn... yet the loco sits still.. all else being equal.... and dips into overload of the circuit....

But follow the step by step Greg is outlining.. 

D


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## Greg Elmassian (Jan 3, 2008)

Dirk, it runs fine for a while, so that rules out one truck permanently wired backwards.

Greg


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## JackM (Jul 29, 2008)

I won't be able to do any actual testing on the SD-45 until later today so let me cover the things that I already know.

- It is sitting on rollers,
- track power, not batteries,
- if it was a bad board, would it run ok at first?
- if I had a spare board, I'd definitely do a swap
- it runs well forever on the rollers, maybe I should remove the extra weights
- wheels all run in the same dirrection
- none of the electrical contacts are brass
- the only brass I recall is between motor and gearbox
- on rollers, I have been able to hold the middle wheel of the front truck stationary while everything else turned (up to half power DC - on the rollers)
- I don't know if I did much to the rear black other than to re-assemble it such that I'm sure proper contacts were made

Does any of t this information help?

JackM


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## SLemcke (Jun 3, 2008)

To me it sounds like one of the two motors on the rear block is bad. Good enough to run on rollers, but when put on the track with resistance from the weight it causes the motor to bog down. Steve


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## SD90WLMT (Feb 16, 2010)

Your comment about "holding" the middle wheels/axle should be a red flag.. indicating a gear train issue...
.... bad or worn gears... miss-alinged .... or. !

Should not affect your diminished power problem. . But will affect pulling power here...

Seems you have more than a single issue to shift thru .. and resolve!

Keep after it ....

D


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## Michael Glavin (Jan 2, 2009)

Jack,

"_on rollers, I have been able to hold the middle wheel of the front truck stationary while everything else turned (up to half power DC - on the rollers)"_

Are you suggesting the center axle is NOT moving while the rest of the drivers are? If so something is amiss in the gearbox I suspect. 

Some of the Aristo blocks have been reported to have issue with the drivers slipping on the driver-axle taper. That said, herein doesn't sound like that is your problem. Perhaps the center gearbox is binding up after it warms up.

If you had known working trucks, perhaps swapping them into the engine would point you in the right direction.

Michael


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## Cougar Rock Rail (Jan 2, 2008)

If I was a betting man, I'd say you might have one of the early motor blocks that had plastic worm gears on the motors. When the motors heat up, they transfer heat down the shaft then it makes the worm slip on the shaft. That would explain why it will run under no load, but not under load, and you can hold one axle while the other still goes. If it does have the plastic worms, you might be able to just remove them and press on an LGB brass worm if they are similar enough.


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## Michael Glavin (Jan 2, 2009)

Perhaps the shared plastic worm of the center gearbox is slipping as Cougar suggests (center gearbox is coupled to both motors), in this circumstance initially the truck is working, later center worm warms up and slips, which in turn causes the center axle to be drug down the rail eventually over heating the decoder with excessive current draw.

Or all the three worms eventually warm up and slip, causing the entire truck to be dragged by the operating truck, again causing excessive current draw and overload of the decoder.

Michael


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## JackM (Jul 29, 2008)

Maybe I should detail this particular situation more clearly. I think I may have sent you down the wrong path.

Testing the SD-45 up on rollers on the bench in the garage, powered by the same NCE equipment that normally runs the layout (I pull out the track plug and connect the track output to the test track via jumpers). Thus, I have full power to the test track (and rollers) less voltage loss due to the thin wires. They never get hot so it shouldn't be an issue.

In the case in question, the SD-45 is a six axle unit sitting on four roller units; the middle axle of each motor block is hanging free, giving me an easy way to check whether or not the wheels are turning, in which direction, etc. I press my finger upward onto the two free-running wheels, the middle wheel of each block. I do not touch the distant wheel of each of these two axles, only the wheel closest to me.

When I increase the Power Cab speed, I am able to hold the middle wheel of the _front_ block steady - not rotating. I can keep that wheel stopped until the Cab is up to, maybe, 10 or 12, at which time I cannot press my finger into the flange enough to keep the wheel stopped. At no time during this test can I stop or even slow down the middle wheel of the rear block. I have not thought to reverse the position of the SD-45 on the rollers in order to do a similar test on the middle wheels of the other side.

I'm not sure that stopping the middle wheel as described shows any problem; it seems to me it shows that that wheel will exhibit wheel slip once the Cab power is high enough. Wheel slip isn't the problem; I should be so lucky.

The problem is that stop, start, stop, start, that it does after traveling only a few hundred feet. That distance would be far shorter if the unit was pulling any rolling stock at all. (All my cars have metal wheels.)

Also, could I expect to feel at least some heat in the area of the wheel/axle/body with my finger pressed there? I would think this sort of issue would create a fair amount of heat.

Perhaps I should run the unit with the body off. I haven't thought to do that since there are so many wires running between the "chassis" and the body. My garage bench is shared with automobile tools and parts. Hard not to lose those teeny screws, etc. But maybe I'd see the QSI unit all aglow. I'll try to do that tonight or tomorrow.

JackM


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## Randy Stone (Jan 2, 2008)

When I thought I was having a problem with my Dash 9 which uses the same motor block, I pulled the motor blocks out, jumpered the contact strips on the top and ran them with power direct from the track to the motors. 

https://www.youtube.com/edit?o=U&video_id=SDZTXqAdPrk


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## Michael Glavin (Jan 2, 2009)

Jack,

While the suspended center axle is held in place, power applied do the other drivers rotate and the center does not?

I wouldn't expect to feel heat from the exterior of the motor block if worms were slipping, especially in the short time it appears to run.

You alluded to the engine being mostly on the shelve for several years, has this engine every operated correctly since you added the decoder, auto coupler and lighting?

There are issues with Aristo's PnP sockets, wiring pin-outs have been known to be inconsistent, and or incorrectly wired at the least. And there is the power pick-up problem Greg describes on his site too.

Michael


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## Greg Elmassian (Jan 3, 2008)

Jack, you say you ran it on rollers, and you say it quits after 300 feet.

Can you make it fail on rollers?

Also, you say you have a PowerCab.. A stock NCE PowerCab system is only 3 amps, could you be overloading it? You will know by looking at panel the cab plugs into, the red led is on when track power is on...

Greg


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## JackM (Jul 29, 2008)

Randy - sorry, I don't have a Google account so I can't access YourTube. At this point, I no longer think either block has a wiring problem. Think, that is. I don't KNOW nothin'.

Michael - when pressure is applied to the middle wheel of the front block, all other DO spin, appropriate to the power applied. The loco has never run properly; I recall it never seemed to have much power, although I can't recall details after a few days, much less years.

Greg - On the rollers it seems to run just fine, although I can't say I've run it long enough to be comparable to the time it takes to run it about 300 feet on the layout. On the layout it is down to start-stop mode by the time it's run about 300 feet.

Are you asking about the red light while the loco is on the rollers or on the layout? The red light is continually ON when it is on the rollers; but I've never thought to check when on the layout. I should be able to take a look at that today.

Guys - I seriously appreciate this question & answer back and forth. I know we'll find the problem. (I'll try to spend some time today scouring Greg's website to see if there's info I missed.)

JackM


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## Michael Glavin (Jan 2, 2009)

Jack,

Sounds like its undisputable that you have an issue with the center gearbox at the very least. All three axles are coupled to both motors, if one axle is not moving an the latter are you got problems therein.

The rollers do NOT emulate real time use, each roller is independent and offers no resistance makes sense the engine can run on rollers without dropping out to me.

Michael


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## JackM (Jul 29, 2008)

I just did some "testing" to make sure I'm giving you the real facts.

Greg - the NCE lights are keeping steady thruout. On rollers, running on the layout or bogged down on the layout, the lights indicate everything is fine.

Michael (everybody, actually) - I got serious on the rollers and pressed harder on the middle wheel (either side) and put some better light on it (garage workbench lighting isn't designed for shadowy subtleties like this). I was surprised to find that stopping _either_ wheel on middle axle stopped all six on that particular block! <--exclamation mark to indicate surprise.

Stopping either middle wheel on either block, up to speed number 15, enabled me to stop that block. Actually, I could stop the rear block up to speed number 20. Above those numbers my skin got "hot" enough to not care to press any further. I don't have another three-axle engine to compare that with. I suppose I could attempt to stop a wheel using something less dainty than my fingers, but hopefully this gives us sufficiently useful information.

So, between this and my previous posting, whadaya think? 

JackM

It's such a nice engine. More graceful and well-balanced than the SD-70, IMHO. Seems a shame to not use it.


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## Michael Glavin (Jan 2, 2009)

Jack,

With this new understanding it now sounds like the motor block center axle is NOT a problem. 

I'd consider going back to the basics, disconnect Kadee coupler mechanism and see what happens. Verify the PnP socket pin-out and wiring harness are correctly configured. If nothing else remove the decoder and test the engine on the rail.

Michael


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## Greg Elmassian (Jan 3, 2008)

OK, cutting out, and the red light on, means track power is fine, and not being interrupted.

I suspect the polyswitches in the loco itself, although they normally do not trip except under very heavy loads, very high ambient temperatures, or defective motor blocks drawing excessive currrent.

So, you need to monitor the current drawn when the loco starts out running fine, and what that current goes to when it cuts out. This will narrow the problem down.

If you are using a PowerCab, set the cab so it shows you current. Also, are you using the stock power supply? If so you have 3 amps and about 16 volts, neither of them is sufficient for good operation.

I'd like verification of your setup.

Greg


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## Totalwrecker (Feb 26, 2009)

Sounds to me like the blocks are running at different speeds causing one block to over heat and trip the polys. On the track resistance is physical, free wheeling, no bind..
Best,
John


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## SD90WLMT (Feb 16, 2010)

Jack.... not to derail here.. but I'm guessing your SD70 may not be of equal weight to the SD45, @ 13 #'s...

They run near 10 1/2 #'s out'a the box...

My unit... @ over 19#'s is all I think your looking for... incredibly slow when needed... terribly smooth both pulling and running a train..!! Short ... or .. very long! It just feels like a real loco...... ;-)

Dirk


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## Greg Elmassian (Jan 3, 2008)

Dirk, unless I'm nuts he's been talking about an SD-45 the entire time. 

Greg


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## SD90WLMT (Feb 16, 2010)

Got'ta take it "alll in" Greg....!!

Last sentence.. #27....

....slow down buddy!!!..


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## JackM (Jul 29, 2008)

My postscript in #27 might have been stated more clearly. That is my opinion of the _visual_ qualities of the SD-45.

My dance card is rather full this weekend. I'll take the 45 down to the basement workbench next week and open it up and see if I see anything amiss in there. 

JackM


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## Greg Elmassian (Jan 3, 2008)

Ahh.... so focused on solving the problem, must have filtered out the distractions.

So Jack,

1. Are you really using a PowerCab, and if so, what voltage do you have on the rails, and what amperage is the cab reading?

2. You can also measure the amps by measuring the DC input current, the amount of power used by the powercab electronics is negligible.

Greg


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## SD90WLMT (Feb 16, 2010)

I may have been quick to pick up on Jack's "curve ball", his own comparative derail.. since it was somethin' I'm a little familiar with in my own world!!

D


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