Farish 4-CEP Problem

[Stevelewis]

Over   around  20  years  I  have  installed  many  decoders  from  Z to  G  Gauge, never  had any   significant  problems, even in  the  early  and  exciting  days  of  hardwiring!

 

However  yesterday  I  encountered  a  problem  with  a  Farish 4-CEP  EMU,  the  unit  is  brand  new  and  it  tested  out  fine  on  analogue,  however  when  I installed  a   decoder  the following  occurred:

 

I programmed  an address  which  appeared to work  OK,  then  placed on  track  and powered up the digital system,  without  doing  anything  else the  unit  in chassis  form  moved  off, ran slowly  for  about 30cm  then  the  decoder   smoked and  every thing  stopped!  Hello  I  thought  a  faulty  decoder,  So  I then proceeded  to install another  decoder  which  I removed  from  a  loco so I knew  it  worked.... same  fault  occurred  , so  silly  me  I suppose  a  tried  a  third 'known' decoder  same  thing  happened.

 

So  being  3  decoders  down  I decided  to  give up,  spoke to  the retailer  and  agreed  a  direct  return  to  Bachmann

 

I was  basically curious  if  any one had  any  ideas,  re  the  fault,  I  suspect  a PCB problem.

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I shall shortly  be  digitizing a  couplee  of  class 40s  with  next18s

[Nigelcliffe]

Sounds like a connection between a motor terminal and the pickups, possibly on the main PCB, or elsewhere in the unit's wiring.

 

I assume you are asking your retailer for replacement decoders for those smoked ?   The retailer can then claim that back from Bachmann. 

 

 

btw.  you probably realise this now, but if a decoder smokes, it is almost certainly due to a fault in the loco.  So, investigate that rather than risk another decoder.    With no decoder or blanking plate, you should be checking no contact between either pickup pin on the DCC socket and any of the other pins on the DCC socket.

 

 

- Nigel

[Stevelewis]

Yes  everything  checks  out as  being  OK,  its  a bit of  a  mystery ,  so  I  shall let  Bachmann  sort it  out,  under  normal  circumstances  I  would  have  either requested  a  retailer  refund or   replacement,  but  as  there  are  none  round  now  and   the unit  is  required for a  project  I will take  the  Bachmann route!!

[Steven B]

The motor feeds are a pair of brass contacts that come down from the PCB. These can make contact with the chassis sides which are connected to the track feeds. This isn't a problem on DC but on DC can let out the magic smoke.

 

Steven B