Dapol Bubbecar 121

[Pierre Le Brun]

I've had problems with the 121. Tested first on DC everything fine albeit not beating any speed records. Problems started when I installed a 21 pin MTC laisdcc chip. Ok I know this is a cheapskate Chinese chip. The loco did not respond, using my Bachmann EZ controller. Though I did detect a brief humming sound. Next replaced the dc blanking chip, the bubblecar did not respond now on dc. Tested track with another dc loco and everything is fine with the track circuit. Sniffed the loco, no obvious signs of burnt or blown circuits. Anyone come across this before. 

Edited February 20, 2020 by Pierre Le Brun

[letterspider]

With this model I remove one of the drive shafts and it runs perfect

Two drive shafts - there appears to be too much friction in both gear trains - although after prolonged running in this does improve

While doing all of these experiments I notice that running with both drive shafts is okay with the body shell off - it appears that everyting is a bit tight inside the chassis and the designers didn't  factor in much slack.

In fact so tight that nothing will turn at all when you close it all up again

I don't remember but I think the drivshafts are single, solid piece of plastic and so no give. Compare that to say a Hornby Class 60 which has a split drive shaft with variable length.

 

I would recommend

body shell off

remove a drive shaft

try on DC and then DCC

 

Good luck

[Pierre Le Brun]

Finally managed to get everything up and running on dcc, not sure why it wouldn't work the first couple of attempts. Reinserted the chip a few times also checked the motor was running freely, as suggested by letterspider as things may have been tight. Did not uncouple the drive as things are now working I thought I'd leave well alone. It's only a 4 function decoder so I've got the following lights, front and back, both cab lights but no coach interior.  Worst case scenario I was going to let Phil Bullock (Abbotswood Junction) have a look at it. 

[letterspider]

Well done.

I have used those decoders - you will probably need to fine tune CV2 and CV3 to stop it shooting off like a whippet!

[08221]

Could someone please tell me how to remove one of the drive shafts - I have 2 very jerky running 121s!

 

Thank you

 

[JohnR]

I've had trouble with the Dapol 121 - I thought the decoder was inserted fully, but it turned out it wasnt. Despite taking it out, testing on DC, then reinserting the decoder, it simply wouldnt work on DCC. Turned out it wasnt fully in.

[08221]

7 minutes ago, JohnR said:

I've had trouble with the Dapol 121 - I thought the decoder was inserted fully, but it turned out it wasnt. Despite taking it out, testing on DC, then reinserting the decoder, it simply wouldnt work on DCC. Turned out it wasnt fully in.

Thanks. 

 

The decoders are fitted in ok (I have checked) as they work when I select their address, just run very jerkily!

[Pierre Le Brun]

On 22/02/2020 at 15:42, JohnR said:

I've had trouble with the Dapol 121 - I thought the decoder was inserted fully, but it turned out it wasnt. Despite taking it out, testing on DC, then reinserting the decoder, it simply wouldnt work on DCC. Turned out it wasnt fully in.

I suspect this is the problem I may have had with the decoder as it refused to work after several attempts and then wouldn't work with the blanking plug. Possibly it needed that extra push. All working now. 

[Pierre Le Brun]

On 25/02/2020 at 13:29, Pierre Le Brun said:

I suspect this is the problem I may have had with the decoder as it refused to work after several attempts and then wouldn't work with the blanking plug. Possibly it needed that extra push. All working now. 

I have now upgraded to Sound and everything works well