I started this as a post in the ToM club thread but have decided to give it its own thread. Let me start by saying that I have this mental disorder where I think I need to buy up repair parts for games that I think are unobtainium. When I first purchased ToM I started researching what parts are hard to come by. The biggest concern was the gearbox/motor part number 14-8018. Add an MC at the end for just the motor. The entire assembly can still be had for 269.99 at Marco's site. Another different style can be had for 230.00 from the pinball resource. I believe this was probably made in China based off of the stock original. Just the motor can be had for 85.00 from Kimball's pinballs. I bought the one from PBR to save a few bucks I also bought the Kimballs motor for 50.00 at the time. I liked the idea of having a complete assembly and a ready service spare to minimize downtime. I figured once the original died I could refurb with the motor and be all set. I played and enjoyed my game for a few years before I finally decided to do a full tear down resto. At the completion of the restore I had issues with the trunk. I did some troubleshooting and narrowed it down to the motor. It is 22 years old and has degraded over time in performance and also got loaded with coil dust and what appears to be a oily residue from the super lube i used to regrease the gearbox. I disassembled at cleaned the motor with Lectra Clean 2, then alcohol to get rid of the residue. No that I know what the problem was I likely could have just cleaned without taking it apart.

IMG_0035 (resized).JPG

IMG_0026 (resized).JPG

IMG_0044 (resized).JPG

IMG_0028 (resized).JPG

When the issue originally occurred I replaced with the PBR gearbox and noticed the trunk spins noticeably faster than what I was used to. I don't know if this is on purpose or was it just that the stock motor was tired. So because this is what I do for a living, I tested it. And I found that the complete stock setup powered up the bench produced on average 13.5 rpm in both directions. Tested it several times for repeatability. Here's the specs. You need a 12 vdc motor with a 2.3mm output shaft. The mounting holes need to be 16 mm center to center. The stock nameplate ECM 6332 12 vdc. 4/95 20 rpm 14-8018 POS/POS CCW rotation.

I decided to refurb my original gearbox with th motor I bought from kimballs as I had originally planned only to find out that the gear pitch is wrong. The gear had a smaller OD so it lacked the appropriate tooth engagement. So installed in the game the teeth just partially worked but skipped a lot. Otherwise a nice replacement. The output shaft is smooth so the original gear will not press fit like the original so it's useless. Unless of course you have a way "dimple" the shaft in order to deform it to allow a press fit. Maybe smash it in a vice to make it work? Essentially the shaft OD is smaller that the stock hardened gears ID. Too sloppy. $85.00 for a motor that you cannot use. I made no attempt to get any kind of refund, as I purchased the motor years ago and didn't try to use it till now. No hard feelings.

So I decided to set out to find a commercial off the shelf one for one replacement that requires no modification to work in an existing gearbox. I also wanted it to be affordable because everything pinball cost too much. ToM is junk without the trunk and it shouldn't cost $300.00 to fix it for who knows how much longer. And I wanted to pay forward for all the great people in the hobby who have helped me. So I'm doing this for free. You know who you are because you do it for the love of pinball and I'm sure I'm not the only one who you've helped over the years.

This is the stock, tired, old, motor in the gearbox.

<iframe width="560" height="315" src="https://www.youtube.com/embed/fEDXWebjtvA" frameborder="0" allowfullscreen></iframe>

Can't get it to just show up in the thread sorry.

Ok so I'm better at electronics than I am at internet. Here is the replacement that can be had for less than $10 on eBay shipped. It is a Mabuchi RS-385SH. This is apparently a replacement motor for a roomba. If you have the ability to pull your original gear off of the existing shaft and then press it on a new shaft, you are in business. Direct one for one replacement that requires no modification to fit.

This averages 20 to 21 rpm in both directions with numerous retests for repeatability. The search continues for the appropriate replacement output shaft gear. I don't really need it, but I like to horde spares.

Here are the only special tools I used to remove and install the gear.

IMG_1233 (resized).JPG

IMG_1234 (resized).JPG

More for anybody who's listening. Did some research on the 12T gear that is attached to the motor. I figured out that it is a 48 pitch gear. I've found that a Traxxas #2428 gear for RC cars will fit perfectly with the exception that shaft is 3.2 mm instead of the required 2.3 mm. I was able to get a spacer to make up the difference. I was able to get this stuff at my local neighborhood hobby store. So if you don't have the ability to pull and press gears. This is a viable option. The new gear has a set screw to hold it in place so no need for a press. One small mod I had to do to make it work was grind down the collar a bit so the first gear could slip on.

IMG_0108 (resized).JPG

IMG_0120 (resized).JPG

IMG_0121 (resized).JPG

IMG_0122 (resized).JPG

IMG_0123 (resized).JPG

More data collected. I calculated that approximate rpm you need to get 20 rpm on the trunk shaft is 12,000. That works out to a 600 to 1 gear ratio. So with a Mabuchi RS-385SH motor, a Traxxas #2428 gear, and the brass spacer listed here, you can repair your original gearbox to its original performance (nameplate). All for less than $15.00.

Yeah at first glance his motor looked good. Had the whole machine back together and you can hear the gear slipping. Definitely the wrong pitch. Here is the teeth per inch just to see the difference.

IMG_0118 (resized).JPG

Left mark 14 teeth per inch. 12.5 teeth per inch for the stock gear. Either way 15 bucks or 85 bucks. You can press the original gear on a new motor for less than 10. I didn't have the same luck. Maybe you got a different gear than I did. I didn't talk Kimball's about it because I had made the purchase so long ago. I wasn't going to try to get a refund at this point. Again no hard feelings it just didn't work in my gearbox.

I think I know what your problem is and I don't think it's motor related. If you watch closely when the opto interupter goes past each opto it actually goes past the switch. When you are testing the light comes on then goes off because the motor kept spinning after it "sees" the switch. Then you try to push it to go in the other direction but none of the switch lights are lit. So the CPU doesn't know where the trunk is and does nothing. You hit the button again and the trunk spins until it "sees" the next switch. How close to the opto board is your opto interupter? Is it barely breaking the plane of the opto transmit receive LED's?

That was just my first guess. I wasn't sure but after thinking about it it seems to register pretty consistently. For some reason the motor continues to spin after it registers the switch. It is a very short duration. I think next guess would be to repin the connectors for the motor control board. I think it's at least a possibility that you have a poor connection somewhere causing this issue. Could be the connections from the opto board to the motor. Could be the opto board itself. Is the stock opto board still good? Can it still be used?

I would swap boards and if that doesn't fix it repin all connectors between opto and motor controller.

I would consider doing this but I don't have a traveling shop. If you wanted to send it to me I could replace the motor and clean and regrease the gearbox and then send it back.

I believe you would have stood behind it. I didn't think it fair to bother you with it since I purchased it years ago. My recollection of the transaction was I received just a motor/gear with no instructions, but it was years ago so I'm not sure. I could not get it to work properly so I made a little project out of coming up with a low cost solution. I hope you do not feel I was bad mouthing your product, that was not my intent. I am not selling anything to anyone so this is not an attempt to undercut your business, all I did was provide some information from some data I collected.

Did you wire the motor backwards? A guy earlier in this thread had the same symptoms you just described and he had the motor wired backwards.

Based on original ToM motor nameplate it should be 20 RPM. With my old motor I was getting 13. Did you watch the videos the guy posted above? Do your symptoms look like this? The final fix was swapping the motor leads for this guy after changing opto boards.