Questions about Dapol Class 121/122

Sven · October 05, 2019, 10:11:55 AM

Recently, I bought the bubble car Class 121 and I have some questions I hope you have the answer:

1. Is the bottom of the Dapol Class 121 exactly the same as the Class 122 they are making? If I look on the pictures, they seem similar. But I would expect two different classes to have a least some differences. Or is the bodyshell the only difference are can they be swapped around?
2. How do I access the motor? I can get the roof off, but how do I open the rest to get to the motor?

I find the documents supplied with the model very limited. It's curious that it doesn't even tell you how to open the model to install the decoder, but I figured that already out. As it is one of my first Dapol models, I was not familiar with the method of installing decoders by taking off the roof. Very nice model, though!

Dr Al · October 05, 2019, 10:20:32 AM

The motor is a female dog (changed by forum) to get at. It's a can unit, and it's housed centrally in the base of he model. You can unscrew the PCB, lift it up (gently - don't pull and damage any wiring), this will expose one of the two screws that holds the seating unit in. This can then be removed to expose the motor.

Getting the motor out from there is still a challenge as there are two plastic crossbars of the body in the way.

Not designed to be disassembled!

Cheers,
Alan

Sven · October 05, 2019, 10:40:24 AM

Thanks for that info. After taking the interior out, I noticed that that actually isn't necessary, as the bottom has to come off the housing. I was able to separate the housing from the bottom with my nails. That said, as the interior is made of metal, taking it out make the housing more flexible and might make it easier to take it off.

Sven · October 05, 2019, 06:44:04 PM

All done now. Installed a coreless motor and light. Runs like a dream now, very slow as well without stuttering. Taking it apart was actually not that difficult. There are gaps on the left and right ends, in the black bottom part, to put your nails inbetween. Will make a thread for this upgrade, I took pictures of the whole process.

robert shrives · October 05, 2019, 06:50:07 PM

yes please on the motor change job ! very nicely done, models were designed to be almost throw away with wiring glued in place and hard to access motor, a design of its time common with 122,153,156 units.
motorsing a dummy might be more straight forward now.
thanks
Robert

Sven · October 05, 2019, 06:53:02 PM

Interesting about the dummy. What's in there already then? Have the wheels the gears and only the motor and worms are missing?

Sven · October 05, 2019, 06:54:53 PM

Here's a quick video with the result:

Dalek · October 07, 2019, 03:18:00 PM

Quote from: Sven on October 05, 2019, 06:44:04 PM
All done now. Installed a coreless motor and light. Runs like a dream now, very slow as well without stuttering. Taking it apart was actually not that difficult. There are gaps on the left and right ends, in the black bottom part, to put your nails inbetween. Will make a thread for this upgrade, I took pictures of the whole process.

Hello, this looks an interesting conversion,

where did you get your motor and how much work was it to fit ? Did you find out if a dummy could be motorised ?

Craig

Sven · October 07, 2019, 03:44:59 PM

I'm selling these motors through the Tramfabriek, see http://tramfabriek.nl/motors.html . I don't have a dummy, so don't know (yet). I think it will take about one to two hours to fit it, depending on your experience. I will be writing a step by step guide this week.

Sven · October 07, 2019, 03:46:25 PM

Oh and the motor used is the 8 x 16 mm with a shaft sticking out on each side. The shaft has been cut to size (26 mm overall length).

njee20 · October 07, 2019, 03:59:52 PM

I'm not familiar with the 121 specifically, but those are long motors, presumably a degree of modification is required to get one into most things?

Sven · October 07, 2019, 05:13:17 PM

Not much actually. You only have to remove some plastic of the tabs that hold the motor in place. The toughest part is getting the flywheels off of the original motor. I'll show you later. I'll try to work on it tonight.

robert shrives · October 07, 2019, 05:17:02 PM

Hi
Re dummy units you will find bogies do not have all the gears in the towers nor shafts and worms - so it might work if you split the drive train over two vehicles- not tried it but given tail loads not that likely you might get a reasonable result.
Robert

njee20 · October 07, 2019, 05:18:56 PM

Given how much cheaper dummies are (not hugely) I'm not sure that'd be worth the effort. There tends to be more plastic bits in some of the dummies too - no metal chassis.

Sven · October 07, 2019, 05:34:54 PM

In the 121 the seats is the metal. The rest is plastic. I would assume the dummy comes with the seats. I think the main thing would be that it would come without the gears. But I think a new model isn't even very expensive (can be had for £107), not sure if one wants to go through the effort of sourcing the missing parts.