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I have an MTH Proto-Sound 1 263e blue comet with a stripped drive gear. I have acquired a replacement gear which I am confident will work with this engine.  However, there seems to be no easy way to remove the old one and replace it with the new one. The two sides of the chassis are permanently attached, and the shaft which is attached to the damaged gear is also attached to a spur gear on the outside of the chassis, holding it in place. Any suggestions for what to do would be greatly appreciated. I've included some images to better illustrate the issue.

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Images (4)
  • Closeup of damaged gear
  • Replacement gear
  • top view
  • side view
Original Post

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Can either the worm and/or the spur gear be removed on your new set, if so I would drill out the old shaft to removed the old spur gear and then cut the old gear shaft out.

Once the bearing are clear and clean, I would slide the new shaft into place and reinstall the gears.

Otherwise you will have to cut the frame to release the bearing and shaft.

Good luck

Last edited by totrainyard

Totrainyard, I might end up doing that. The only problem is that the gears seem to be permanently attached to the shafts. I have heard that metal gears can be removed from the shaft if you heat them up with a blowtorch, which I unfortunately don't have access to at this time. I tried using a soldering iron instead, but that didn't work. I'll have to find another way to heat them up. Anyway, thank you for the suggestion! 

Jon G, do you know where I can buy one of those replacement gear assemblies? The MTH website has a parts search, but I can't find the option to buy a specific part. I was able to find this part, which appears to be similar to what you described, but the sizes of the gears don't look like they match the ones on my blue comet. Is there a different part I should be looking for?

Jon G, do you know where I can buy one of those replacement gear assemblies? The MTH website has a parts search, but I can't find the option to buy a specific part. I was able to find this part, which appears to be similar to what you described, but the sizes of the gears don't look like they match the ones on my blue comet. Is there a different part I should be looking for?

The part you identified is for Std Gauge ProtoDrive motors.  They have both the individual O-gauge worm driven gears and the whole assembly.  Once you replace it with the new version, the worm driven gear will be easily replaceable.  Deb had a bag with those new gear assemblies and there is a part number assigned, but it may not have been posted yet.  Still furloughed, so I can't help with the part number, but Midge can check with Deb if you email her.

As for why it wore out, it's sacrificial so the worm gear on the motor doesn't wear out.  But, it's Chinese brass, so don't pull heavy loads, don't run it in a museum setting and keep it lubricated (not the easiest thing to do).

Roy, I'm not exactly sure what happened, but my theory is that the grease that was on the gears got old and started to harden, thus damaging the gear. When I took the locomotive apart, the motor's worm gear was almost completely submerged in thick grease which had turned green. I've removed almost all of the old grease, and I plan on doing a more thorough cleaning before I put in the new gear, so hopefully this doesn't happen again.  Jon, I had a feeling that the gear I was looking at was for standard gauge. I'm glad I didn't buy it right away! I contacted Midge about this a while ago, but I don't think I ever got a response. I'll definitely contact her again, now that I have a better understanding of what to do.   

So I went back and looked at my notes.  First, you can press the shaft off.  Gears are pressed onto a splined/swaged shaft.  I have replace gears on diesel trucks and other engines.  The key in reassembly is location of the new gear and using spacers to ensure it gets positioned correctly during installation.

The new part assembly MTH came up with is now TP-OE00147.  This is a complete shaft and gear assembly that will not require pressing.  I have one in stock if you needed it. 

To get the old shaft off, you could press out on the side opposite of the idler.  Use a spacer to keep the damaged worm gear from moving as the shaft is driven out.  G

@GGG posted:

So I went back and looked at my notes.  First, you can press the shaft off.  Gears are pressed onto a splined/swaged shaft.  I have replace gears on diesel trucks and other engines.  The key in reassembly is location of the new gear and using spacers to ensure it gets positioned correctly during installation.

The new part assembly MTH came up with is now TP-OE00147.  This is a complete shaft and gear assembly that will not require pressing.  I have one in stock if you needed it. 

To get the old shaft off, you could press out on the side opposite of the idler.  Use a spacer to keep the damaged worm gear from moving as the shaft is driven out.  G

G, thank you for the information. Do you think I could remove the old shaft with a hammer and punch instead? I don't think I have access to a press of any kind.

Sockets and vise.  While I had a lionel press I never used it.  I do all my work with the bench vise and various sockets and broken drill bit to press wheels, and gears.  Punching is not the method to use.  I do use the flywheel and wheel puller that Timko makes, but the internal gear swaps and such are just basic tools and the vise.  C clips and flat steel can be used as spacer if needed.  G

I don't pound things out unless there's no other way.  I do have a press, and I use it for stuff like this is there's a way to brace the surface to avoid bending anything that I don't want bent.  Looking at this one, I'd probably go with Jon's method and chop it out with the Dremel.  Since the replacement doesn't need any pressing, that avoids any possible damage to the motor frame.

Thanks to GGG and the parts he provided, I was able to get the engine running perfectly again! I've held off on completely reassembling the engine though, because I just remembered that I need to replace the smoke unit. I talked to Midge about a replacement, and the only one she has at the moment has a brass funnel which does not match the one on my engine. Is it possible to remove the funnels and swap them?

Why do you think you need to replace the smoke unit?  Typically, unless they've run away and cooked the PCB, a simple rebuild is all that's required.

As for removing the funnels, some screw in, some are permanently mounted.  If you have one that's permanently mounted, it was pressed in, and removing it will leave it loose forevermore.

I brought this engine to an authorized service center back in November because there were problems with the sound system. The guy was able to fix it, but he said that the smoke unit also broke. He gave the engine back to me and said he would call me when he found a replacement smoke unit. I decided that, since it's been so long, I should try to fix it on my own. I disconnected the smoke unit and tested it, and I couldn't hear the fan spinning. The funnel on this smoke unit seems to be pressed and glued into place. 

PS-1 smoke boards can be repaired.  As long as you did cook the PCB so bad that traces disappeared or burned the fiber.  If you put a picture up, may have the top board assembly.  Worst case is the stack can be removed from the bad PCB if it is damaged.  Swedged and reinstalled in another.  Epoxy is your friend, if really damaged.  Normally though, just rebuild the unit.  I can do it if your not sure what is wrong and some of the electronic parts are damaged.  G

@GGG posted:

PS-1 smoke boards can be repaired.  As long as you did cook the PCB so bad that traces disappeared or burned the fiber.  If you put a picture up, may have the top board assembly.  Worst case is the stack can be removed from the bad PCB if it is damaged.  Swedged and reinstalled in another.  Epoxy is your friend, if really damaged.  Normally though, just rebuild the unit.  I can do it if your not sure what is wrong and some of the electronic parts are damaged.  G

The motor works fine when tested independently of the board, so the board has to be the issue. I can't tell which component

of the board failed, but some of the solder points in the right picture look burned. Maybe that has something to do with it.

 

IMG_4663IMG_4664

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Images (2)
  • IMG_4663
  • IMG_4664

I just replaced the voltage regulator circled in my last reply, but nothing happened. I then removed the plug with the red and black wire and attached it to the other socket, and I put the plug with the motor wires in the other socket. I did this because the socket that originally had the red and black wires was labeled "motor", so I thought I had the wires wrong spots. When I tried it again, the voltage regulator under the one I replaced started burning. Can this smoke unit still be salvaged, or am I better off just buying a new one?

@GGG posted:

Yes, but looking at your picture you are correct AC was plugged into the wrong spot so possible several of the transistors and cap are shot.  If you wan to send to me I can look at it.  I may also have that specific top board in my parts.  G

I have a feeling it's the cap. I tested the 2sb772 transistor with my multimeter and was getting readings, so I assume that one's ok. I'm going to replace the cap, the KTA1266 transistor (which was the one that burned up), and the 5v voltage regulator since I still have a few left over.

@Mallard4468 posted:

A tremendous amount of work - congrats on getting it running.

I hate to mention it, but it looks like the headlight was on at idle and went off when it started moving forward.

Thank you! The headlight only went out because I cut the power for a second to get it moving, and only brought the power back up a little bit so that it would start slow. These Proto-Sound 1 engines are conventionally controlled only, so the brightness of the lights will fluctuate. 

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