Dapol 122 running issue - wheels spinning?

[Matt]

I had one driveshaft go exactly as described- repaired it and really pleased with myself that all back together and working and a few laps later other shaft has gone same way.  It’s now on the round tuit shelf…

[Pteremy]

I have one to repair but I am planning to remove one of the shafts when doing so (as others have done).

 

Interesting to note that these 'duds' still go for over £50 on eBay - must be a lot of repair work going on.

[atom3624]

Does it have a plastic drive cup inside the brass balance weight - perhaps it's just spinning inside the weight - not a snug fit?

Apologies if already mentioned.

Al.

[LittleRedTrain]

Just hit similar problems.
Received a pre-owned Chiltern 121 and after running about 6ft on the test track, one of the bogies locked up. I'd normally just have sent it straight back to the retailer, but it turns out that it had DCC sound fitted (not advertised by the seller as such), so was even better value for the bargain price I'd paid for it believing it to be analogue!

Thought I'd get my Regional Railways one out to compare (bought new, has had very little running and was fine when I put it away), only to find that the motor spins but none of the wheels turn.

Have just ordered enough replacement driveshafts to cover both (plus a third one which is still working for now), so looks like I'll be doing some surgery this weekend. Wish me luck!

 

[LittleRedTrain]

On 02/11/2022 at 00:17, LittleRedTrain said:

Have just ordered enough replacement driveshafts to cover both (plus a third one which is still working for now), so looks like I'll be doing some surgery this weekend. Wish me luck!

Parts from DCC Supplies arrived at the weekend and I had some time tonight to look at the Regional Railways unit:

Discovered that the motor ends of both driveshafts were completely knackered, and the bogie ends weren't much better (plastic bit came off t as I pulled them out). Not great given how little time the model had on the clock!

Replacing them was a bit of a fiddly affair. In the end, I ended up unsoldering the pickups from both ends of the PCB to give me more flexibility to work. I also unscrewed the motor which gave me more play to get the new shafts back in. In hindsight, I might have been able to get away with just doing that in the first place without having to disconnect the bogies.

Finally got it all back together and seems to be running nicely with both bogies powered. Fingers crossed it stays that way!

The Chiltern one (with the seized bogie) will have to wait for another day, but at least I've got a good idea of what I'm facing now.

[Damo666]

On 02/09/2022 at 10:28, dj_crisp said:

I'm kinda expecting every Dapol 121/122 to eventually have the spinning problem.

 

Replacement drive shafts or burring the existing drive shaft and superglue the knuckle on will help sort this. I think this part of the design is the weak link due to a really powerful motor, slightly stiff gears and the close proximity of grease.

 

It's not a difficult fix but still a bit of a pain.

 

 

For my 122s I've used a Dapol body on a Bachmann Chassis. A bit of hacking to the 122 body is needed but other than that it turned out OK.

Hi @dj_crisp

 

Thanks for your post, it's been helpful.

 

I got the Dapol 121 as a present last year, and only got around to looking at it this weekend, and found that one of the bogies isn’t running.

 

The motor rotates, and the shaft to the bogie under the DCC chip rotates, but the opposite shaft is stationary. It seems to be slipping  or not connected at the black connection beside the brass flywheel.

 

Is this the same issue you’ve experienced?

 

Could you kindly advise how to take out the motor. I’ve removed the 4 screws but it’s still kept in place by the two wires and the 2 driveshafts. If I desolder the wires I still cannot see how to remove the motor as the drive shafts are ‘wedging’ it in.

 

Appreciate any guidance.

[LittleRedTrain]

I did this repair to one of mine just this afternoon. 

If you unscrew the PCB (one screw each end) you can lift it up and then lift the motor. That should then give you enough play to disconnect the drive shafts between motor and bogie to carry out the repairs. (i just replaced mine with new spares).

If that doesn't give enough access, you may want to try disconnecting the wires from one bogie at the PCB end and/or removing the bogie retaining screw. 

 

Note that the drive shafts do click into the bogies so need a bit of force to remove. 

If the plastic end has come off either end, you may need to remove the remains with tweezers or a small screwdriver. 

Just take care to avoid putting too much tension on the motor or bogie wires as the connections are not very strong. 

 

Hope this helps. 

Edited March 11, 2023 by LittleRedTrain

[dj_crisp]

1 hour ago, Damo666 said:

Hi @dj_crisp

 

Thanks for your post, it's been helpful.

 

I got the Dapol 121 as a present last year, and only got around to looking at it this weekend, and found that one of the bogies isn’t running.

 

The motor rotates, and the shaft to the bogie under the DCC chip rotates, but the opposite shaft is stationary. It seems to be slipping  or not connected at the black connection beside the brass flywheel.

 

Is this the same issue you’ve experienced?

 

Could you kindly advise how to take out the motor. I’ve removed the 4 screws but it’s still kept in place by the two wires and the 2 driveshafts. If I desolder the wires I still cannot see how to remove the motor as the drive shafts are ‘wedging’ it in.

 

Appreciate any guidance.

 

Sounds like exactly the same experience I've had with them. Littleredtrain gives an excellent description on how to slip the drive shafts out and I didn't need to remove the motor to do mine. 

 

Good luck!

 

Will

 

[Damo666]

2 hours ago, LittleRedTrain said:

I did this repair to one of mine just this afternoon. 

If you unscrew the PCB (one screw each end) you can lift it up and then lift the motor. That should then give you enough play to disconnect the drive shafts between motor and bogie to carry out the repairs. (i just replaced mine with new spares).

If that doesn't give enough access, you may want to try disconnecting the wires from one bogie at the PCB end and/or removing the bogie retaining screw. 

 

Note that the drive shafts do click into the bogies so need a bit of force to remove. 

If the plastic end has come off either end, you may need to remove the remains with tweezers or a small screwdriver. 

Just take care to avoid putting too much tension on the motor or bogie wires as the connections are not very strong. 

 

Hope this helps. 

Thank you LRT.

 

I had wondered if the 4 screws below the motor was needed to lift the motor up, from what you are saying this is not the case.

 

I'll order two drive shafts from DCC Supplies and tackle it when they arrive.

 

Once other little problem I've got. When I opened the box a little screw in a 'plastic sleeve' dropped out. Found out later that this was for the bogie.  The 'Plastic Sleeve' was the raised shaft to fix the bogie to the metal bar, broken off. Would superglue be the right solution here?

 

 

Edited March 11, 2023 by Damo666
clearer image

[LittleRedTrain]

16 minutes ago, Damo666 said:

I had wondered if the 4 screws below the motor was needed to lift the motor up, from what you are saying this is not the case.

The 4 screws at the corners of the motor will need removing too I'm afraid. 

They're also a pain to get back in as they have a habit of sticking to the magnetic motor! 

 

Regarding the damaged bogie, gluing it will probably be OK but you could also see if DCC Supplies stock the frame as a spare. 

[atom3624]

Probably mentioned previously:

1. Are the drive cups rotating in the flywheels - I presume this is all wheel drive / centre motor / dogbone drive to bogies?
2. Is this happening on tighter radius curves - perhaps the dogbones aren't long enough?
3. Is it a poor fit of the dogbones in the drive cups / slots opened up slightly?

Al.

[andyman7]

1 minute ago, atom3624 said:

Probably mentioned previously:

1. Are the drive cups rotating in the flywheels - I presume this is all wheel drive / centre motor / dogbone drive to bogies?
2. Is this happening on tighter radius curves - perhaps the dogbones aren't long enough?
3. Is it a poor fit of the dogbones in the drive cups / slots opened up slightly?

Al.

The main cause of failure was the use of plastic flywheel ends on a metal shaft - this plastic bit splits and is then not held tightly by the shaft. The part has been modified so that the end of the metal shaft is roughened to provide better grip on the plastic end parts.
 

Many people have also removed the shaft and associated bogie gearing from one end as a 121/122 doesn't really need all wheel drive and doing so reduced stress on the remaining drive shaft

[Damo666]

On 11/03/2023 at 21:01, LittleRedTrain said:

I did this repair to one of mine just this afternoon. 

If you unscrew the PCB (one screw each end) you can lift it up and then lift the motor. That should then give you enough play to disconnect the drive shafts between motor and bogie to carry out the repairs. (i just replaced mine with new spares).

If that doesn't give enough access, you may want to try disconnecting the wires from one bogie at the PCB end and/or removing the bogie retaining screw. 

 

Note that the drive shafts do click into the bogies so need a bit of force to remove. 

If the plastic end has come off either end, you may need to remove the remains with tweezers or a small screwdriver. 

Just take care to avoid putting too much tension on the motor or bogie wires as the connections are not very strong. 

 

Hope this helps. 

Again, thank you for your previous reply.

 

Received the replacement driveshafts at the weekend and am about to set to fixing the model.

Noticed that one end of the driveshaft is slightly reduced in diameter. As I haven't removed the existing driveshafts yet it may become obvious why it's like this. But I like to know what I'm getting into before I have lots of small parts lying around, so just in case, is it important which end of the shaft goes to the bogie?

[LittleRedTrain]

1 minute ago, Damo666 said:

Noticed that one end of the driveshaft is slightly reduced in diameter. As I haven't removed the existing driveshafts yet it may become obvious why it's like this. But I like to know what I'm getting into before I have lots of small parts lying around, so just in case, is it important which end of the shaft goes to the bogie?

I have to say, I didn't actually notice any difference in the ends on mine, maybe I just got lucky and managed to get them in the right way round.

The bogie end needs to make a definite 'click' to lock it in place. Presumably if one end doesn't work, try the other.

[Pteremy]

I don't recall which way round they go - if I had to guess I suspect that the reduced diameter has something to do with clearance in the bogie/gear unit. But the key thing is that the revised shafts have grooved ends whereas the originals were/are smooth. That redesign must be intended to reduce the failure rate.