How to dismantle a DAPOL Class 121

[rjonathanr]

When I tried to run my 121 from a Bachmann EZ Command Control, after 18 months in a box, all the lights lit up brightly and it emitted a high pitched whine/buzz as soon as it was placed on the track. I suspected the decoder and have changed that for a Bachmann 6 pin one - the new verion.

It then started to buzz only when the control was moved off zero - but no movement at all.

I removed the bogies and managed to rotate the worm shaft with a sharp instrument and tried again with power applied directly to the pick ups. The moter whizzed for about two seconds and then went * CLUNK* after which the engine appears completly dead.

I feel that I have probably detroyed the new decoder and will try it in another loco, but meanwhile I would like to inspect the motor itself. I presume that the brown floor/seats have to be removed but need advice before I destroy the engine completely. Trying to prise the black baseplate off the sides didn't work.

Thanks for any help offered - or direction to instructions somewhere else.

Jonathan

[robert shrives]

Hi , firstly sad to read and hope decoder ok.
To dismantle is a pain but possible I have parted them with some pain. The body is held on by many little tabs but you might be in luck with this method:
Remove roof
Remove glazing
unscrew seatweight - you need to remove glazing to get it out.
You might now have access to motor and need to go no further.  If not or have mad desire to go further :
Unglue and carefully remove exhaust pipes
unscrew PCB  to give some wire slack
desolder top LED or use a thin screwdriver to break glue join on LED mount - not a lot of wire slack on this bit - a real pain and dont forget you need to do this both ends
With the roof less body in hand use other to gently twist the underframe moulding and inset a thin fillet of plastic to pull body of locating lugs and continue until an end of chassis starts to drop free.
Now remove ligting unit from under cab - light guides are fragile and need to be carefully pulled from body as you ease unit , you will now have used 5 hands to get this far !
As chassis drops clear further you should be able to ease PCB and brake end lighting unit out and around body reinforcement strips.
At this point you should now have a chassis disconnected from a pretty bare body - put roof back on to keep rigid  and you need a small box to keep glazing ok - wrap in tissue to aovid scratching.

Along time ago Dave Jones told me that the model was designed with a low end user maintenance expectation - like 153 and 156 models as such swapping unpowered bodies and powered bodies around was never expected !     

As ever good luck and such messing will instantly void any warranty 
Robert     

[rjonathanr]

Thank you Robert for your very detailed reply.  I have gone down the easy route, managing to rmove the floor with only one side of the glazing extracted. Unfortunately I was a bit brutal and did crack one of the panes.

I have found that the motor will only rotate through half a turn. even with the worm shafts removed. I also tried both the old decoder and my new £25 one in another loco and they are both dead - so it has been rather expensive couple of days.

For the moment the 121 is going into the pending box but I will keep your extremely helpful reply for the long winter evenings when I am brave enough to delve deeper into the assembly.

I have a small model layout to get ready for November with quite a few repairs needed and the weeks soon slip away.

I will certainly let you know if I have any more success

Thanks again

Jonathan

[dodger]

Looks as though the motor is defective, but neither Dapol or DCC Supplies list a replacement. It is possible it is the same as that fitted to another model.

Dodger

[Mustermark]

Thanks for that, Robert.

I tried a couple of years ago so I could fit a headcode. It's been on my to do list since. I guess I will not be going down that route now. It's no wonder I gave up!

[Vanders]

Along time ago Dave Jones told me that the model was designed with a low end user maintenance expectation - like 153 and 156 models as such swapping unpowered bodies and powered bodies around was never expected !

Having a done a body swap on a 121, that sounds about right. As it happens I managed to do mine without unsoldering anything, but it was extremely tricky just getting the body off and then getting it back on again, especially the lights: I did it eventually but I don't think I'd ever want to try it again!

[ntpntpntp]

@rjonathanr can you post a piccie of the motor?  Might help anyone who may know of a suitable replacement or equivalent.

What you describe (motor turns then jams) sounds very much like a brush/commutator/coil segment has become detached and lodged. Usually fatal, sadly.   

A real shame that it seems to have blown your decoder also. In your first post you described the model as lighting up and buzzing immediately you put it on the track, that rather sounds like maybe it didn't have a decoder fitted, just a DC blanking plug?

[rjonathanr]

Hi, I am afraid that you have found me out! I realised when I was putting all the bits away , that the 'decoder' looked a bit simple for a decoder. I had handled it a number of times during the evening and never twigged. I must have swapped the fitted decoder some time in the distant past and completely forgotten. Had I realised the first time that I took the engine apart I would never had bought and fittened a new decoder and then fried it.

In hindsight the behaviour of the engine should have immediately signalled what the problem was. I shall know next time!

Robert has very kindly offered to have a look at the engine for me so it is winging its way in that direction.

Thanks to everyone who pitched in on this topic. It is the first time that I have used the forum seriously to get help and it will be an essential part of my toolkit from now on.

I am getting my small layout ready for an exhibition on Hayling Island in November and will post a few photos once it is suitably photogenic again.

Thanks again and cheers.

Jonathan

[rjonathanr]

Success! Thank you Robert for restoring my 121 to full health. Seeing it run round the track again is great and, I believe, the headcode light is working for the first time, some basic manufacturing faults having been expertly corrected  by Robert.

So thanks to all who helped. I have certainly learned one thing. If you put an engine on DCC track and it emits a high pitched buzz and the lights twinkle, TAKE THE POOR THING OFF STRAIGHT AWAY.

Cheers

Jonathan