Fitting a decoder to an Hornby X04 motor in a 1970s era pannier tank help?

[GWR88]

Evening all,

A friend of mine is struggling to fit a DCC decoder to a 1970s era Hornby pannier with an X04 motor. He's done many installations in his time but this ones stumped! He's already blown one chip after not isolating it all properly so can anyone advise a way of fitting a chip as he is not having much luck! He thinks the problem is isolating the chassis from the motor.

Thanks all in advance,

Lloyd

[Phil S]

BOTH BRUSH HOLDER SPRINGS (ie both ends of 'the spring' NEED ISOLATING SLEEVES over them  - Hornby provided one.

You can either make another with an offcut of a suitable spare piece of wire sleeve - but ensure it is substantial enough not to melt or wear through,

or you could cut the Hornby piece in half - they are usually long enough to do this.

 

REMOVE any capacitor soldered firmly across the terminals - if these connectors are stiff, they may hold the brushes away from the comutator.

If you want to retain the capacitor (value 104 = 1nF) then solder it via more flexible lengths of wire so that the full brush spring pressure is maintained.

 

CHECK with a METER that both brush terminals are isolated from the chassis and pickup paths.

 

If possible measure the NORMAL running current and STALL CURRENT of the motor ... it will be LARGE !

(A Maplin Bench Power Supply with digital readout of current and voltage is useful for this)

 

If the current is very large, then you may want to look at a replacement NEO magnet for it

 

Then go and choose a suitably rated decoder ... it will cost more than many.

 

My final solution was to buy replacement Bachmann Chassis for them, or even later Hornby 'generic' 0-6-0T chassis- because the later motors take less current,(and have more pickups.??)

 

Ensure that, once the body goes back on, NO PART of the decoder can touch chassis or any part of the motor.