9V motor issues - replace or convert to Power Functions?

[Tannerman]

Long time reader, first time poster. So back in 2002 I picked up 4535 LEGO Express Deluxe to run around our Christmas tree. It features a 10205 My Own Train engine and tender with 9V motor and light package.

I typically only run it around the holidays (after cleaning all the track, etc), but over the past few years I've been having issues with the motor. This year I'm noticing that it just runs for awhile... and then stops, almost as if its overheating or something. If I wait a while (5-10 minutes), the motor seems to work once again. My gut is that the motor is giving out on me finally, but wanted to confirm with those in the know.

That said, if my 9V motor is failing, I'm looking at affordable next steps -- and also trying to keep a 4-year-old boy pretty happy. Do I suck up secondary market prices and buy another 9V motor or do I make the jump to Power Functions? If the latter, then I don't know really where to start regarding what I'd need to purchase from BrickLink, etc.

Any help or advice would be appreciated (Also, if anyone has successfully converted this engine/tender combo to PF, I'm all ears).

Thanks in advance!

- Steve

Edited December 1, 2015 by Tannerman

[M_slug357]

Bend Your Knee To The Will Of Power Functions!

[dr_spock]

Sounds like there is a thermsistor stopping the motor when the temperature gets too hot. It is either the motor getting too hot or the old thermsistor is kicking in at a lower temperature. How's your soldering skills?

[zephyr1934]

Indeed, it looks like the new 9v motors are starting to dry up. There have been some good threads about refurbishing a 9v motor using parts from a PF motor and/or renewing the electrical contacts. If you are savvy with a soldering iron that would probably be the best route to go.

If you do go PF, the 10205 locomotive doesn't really offer much room to hide the PF components. The simplest solution might be to build a powered boxcar to house the PF components. You would need a motor, decorative sides (which are different from the 9v), IR receiver, AAA battery box, and PF controller. Since these parts are only available in train sets or directly from lego, the best bricklink prices are usually comparable to lego, so without a lucky sale they'll run you probably around $50 (assuming you do not go the route of the more expensive, rechargeable battery box). At this point, you might be better off just buying a train set, the current passenger train is $125 at Amazon and has all of the PF components with it.

Or instead of a boxcar, you could build another locomotive, e.g., MOD the Emerald Night into a different color... but that is yet another discussion (grin)

[jtlan]

Sounds like there is a thermsistor stopping the motor when the temperature gets too hot. It is either the motor getting too hot or the old thermsistor is kicking in at a lower temperature. How's your soldering skills?

Simply opening up the motor, shaking the thermistor out, and putting it back together should be sufficient.

If you do go PF, the 10205 locomotive doesn't really offer much room to hide the PF components.

Disagree? Battery box should fit in the tender, receiver in the cab, and the PF train motor under either of the two trucks or in the tender.

[Redimus]

At the moment, the difference in the price between a second hand 9v motor and PF motor/receiver/battery box is still in favour of the 9v motor, so I'd stick with that (assuming you can't fix it) for now. For me, the real issue isn't the price though, it's the compromises you have to make to fit PF.

Disagree? Battery box should fit in the tender, receiver in the cab, and the PF train motor under either of the two trucks or in the tender.

I doubt it, the tender on that set is smaller than one of my MoCs which I've tried (and failed) to satisfactorily convert to PF, it won't hide the full sides and there's no chance at all of covering the top of the box without some significant redesigning. You'd need a much taller tender which would look really weird on an engine that size.

[coreyg]

Indeed, it looks like the new 9v motors are starting to dry up. There have been some good threads about refurbishing a 9v motor using parts from a PF motor and/or renewing the electrical contacts. If you are savvy with a soldering iron that would probably be the best route to go.

I've had to refurbish about 8 9v train motors in the past several weeks. Since you have the MoT motor, the good news is that the dc motor itself (almost certainly) can be replaced with the internal PF motor if it's needed but you probably don't need to.

I'd recommend, opening up the 9v train motor, I use an X-Acto to cut the 12 clips on the bottom, (don't worry, what's left will still hold the bottom of the motor), take the thermistor out. The thermistor is a very thin round piece that is smaller than a dime that's in between 2 contacts right next to one of the metal strips on the motor itself. Make sure the contact between motor and the box is still good and close it up and try it out.

There's a couple videos on youtube showing opening the 9v train motor. Don't worry about the rest of the steps since you most likely won't need to replace the dc motor and even if you do, you have (almost certainly) a slightly different 9v train motor than what they are showing. They have the older version which doesn't fit the pf motors.

Once the thermister has overheated once, it does seem to have problems later and just seems to keep getting worse.

If you still have issues after removing the thermister, you can actually remove the motor itself and replace it with a pf motor and since you only have the one train, you can actually solder the contact strips from the old motor to the new motor. The MoT train motor uses the same form factor for the dc motor that the pf motor uses except the leads are reversed. So, if you do this, the motor will go backwards, but you don't care about that with only the one train.

Most likely though, it's the thermistor. Just remove it and everything should be happy.

-Corey

[Tannerman]

Thanks everyone for your feedback so far. Probably the easiest thing for me to start with is the suggestion to remove the thermistor. Before I go down that road, could you help me visually identify the location?

I assume it's the little black item noted accordingly here:

Edited December 2, 2015 by Tannerman

[coreyg]

Thanks everyone for your feedback so far. Probably the easiest thing for me to start with is the suggestion to remove the thermistor. Before I go down that road, could you help me visually identify the location?

I assume it's the little black item noted accordingly here:

The black thing should be a capacitor based on where it is. The thermister is a thin shiny disk that was touching the lower right contact on your motor (based on your second image). In your first picture, it is in the upper right under the axle that the gear is on. It's pretty small.

[Lazarus]

Go though some of my old threds or my youtube account and I have a walkthough on replacing the internal motors.

Good news from the look of the internal motor you have the rare 9v version (from my research this is the my own train replacment motor that came out just before 9v was killed).

This is really good for fixing, that internal motor is a streight swap out for the PF internal motor, not much messing need just solering 2 wires back on.

From what you are saying the fault is removing the thermostat will only help maybe buy for a few more mins run time. the issue is the internal bushes on the internal motor a very common fault and only can be fix by the above.

- Some of the comment from above are a little untrue.

- Both versions of the 9v motor can be fixed with a PF motor (i have 12 of the common type and 1 MoT one all had the internals replaced)

- One just needs work but it is still a very easy job to fix.

Edited December 5, 2015 by Lazarus

[coreyg]

Good news from the look of the internal motor you have the rare 9v version (from my research this is the my own train replacment motor that came out just before 9v was killed).

This is really good for fixing, that internal motor is a streight swap out for the PF internal motor, not much messing need just solering 2 wires back on.

From what you are saying the fault is removing the thermostat will only help maybe buy for a few more mins run time. the issue is the internal bushes on the internal motor a very common fault and only can be fix by the above.

- Some of the comment from above are a little untrue.

- Both versions of the 9v motor can be fixed with a PF motor (i have 12 of the common type and 1 MoT one all had the internals replaced)

- One just needs work but it is still a very easy job to fix.

I have not been successful grinding down the plasic ring to fit the motor body correctly so I've given up on that personally and I'll use those for power pick ups for real pf train motors.

Actually, based on that picture, that's the older 9v train motor which will need the PF motor modified to fit (grind down the outer plastic around the gear). The difference between the 2 types of 9v that I notice is whether the 2 contacts are soldiered at the top (the new one) or have the little punch throughs in the middle (the older one).

I had thought all of the MoT motors were the newer type (what Lazarus calls the rare version), so if this did in fact come from a MoT motor, that is bad news to me since most of mine are MoT (from the small motor set). Although, so far going through about 10 motors, I think 7 of them are the "rare" type and most of my motors came from MoT, but not all.

I had not realized that removing the thermister is a short term solution. Obviously, if the motor overheats, it will have issues, but I had hoped that it was well beyond where the thermister first fails.

I just started removing the thermistor a month ago and so far about half of the failed motors were "fixed" with just removing it and for the other half, it was the dc motor itself.

I've been running a lot of trains in the past 2 months. We had a store front display up for 6 weekends and the trains were running all day Saturday and Sunday (swapping them out mostly every hour). And a lot of these failures happened at previous shows and I didn't pull them out.

Only running the trains for about an hour at a time and then letting them rest has helped prevent failures a lot. Most of the failed motors showed up after a train was running for more than 2 hours at one time.

Go though some of my old threds or my youtube account and I have a walkthough on replacing the internal motors.

Also, I'd like to thank Lazarus for those youtube videos, even though I didn't get the motor grinding worked out, it did help a lot on everything else.

[Lazarus]

Ok the image with the blue arrows i though was the internal motor you had, this is the streight swap one.

The motor grinding is the hard part, i do it with a dremel. you can try with a knife but the plastic is quite hard.

but you could always go the way of buying new 9v motors but i dont have that sort of cash and find ways to save money.

No i just buy busted 9v motors and fix them.