Split frame conversion to DCC

[WilliamDavid]

I have a number of rather nice split frame locomotives that I want to convert to dcc, after having successfully converted most of my Hornby Ringfields.

I have modified a J39 which is is in need of a decoder. Is the Hornby R8249 man enough for these motors?

[poliss]

Carry out a stall current test as described on Brian Lambert's website and then check against the decoder specs.

http://www.brian-lambert.co.uk/DCC.html#NORMAL

[WilliamDavid]

Just checked the J39. It measures about 0.88 amps when stalled.

I gather a fairly beefy decoder is required.

[poliss]

Shouldn't be that high. Loco and motor probably need a good service.

[WilliamDavid]

It is serviced and runs like a dream on dc.

I wouldn't have thought stall current would be affected by the mechanism, as a stall is a dead stop.

I've decided not to waste any more effort on split chassis types. There is a tendency for the plastics to crumble.

Not the finest of mechanisms.

[WilliamDavid]

Just checked a 4MT which draws about 0.9 amps when held stalled. Draws about 0.18/0.2 when moving.

[Fishmanoz]

Plenty of 1 Amp decoders around if you want to try to convert.

[WilliamDavid]

Plenty of 1 Amp decoders around if you want to try to convert.

 

 Cheers.

I have made three 'dcc ready'. Seems a case of risking whatever a 1 amp decoder costs, and deciding if the locos are worth bothering with.

 

[Fishmanoz]

Shouldn't be a risk.  When they say 1 Amp, usually means continuous and they will survive a short burst of higher current. What they won't survive is a motor connection being shorted to chassis where chassis is carrying one side of track volts.  So make very sure your conversions are isolating that.

[Teedoubleudee]

I use Hattons 1.1A at £10 each.

[WilliamDavid]

I use Hattons 1.1A at £10 each.

I have used these on a number of other 'normal'  locos with no issues, so am I to understand these would be fine on split frame types?

I presume one with the spec. below would not be too happy?

Continuous Max Motor Power: 300mA to allow for all functions being active at 100mA each at same time as motor is running, keeping the total power output to under 1A max.

Short Duration Peak Motor Power: 500mA

Function Output Power Rating: 100mA per output 

 

 

 

[96RAF]

I would say you are absolutely correct WD.

You seem as if you need a decoder that has 1 amp max to the motor plus what it can feed the function wires.

[WilliamDavid]

Thanks all for your input. Some of my Bachmanns are too nice to scrap off. 

I will give the Hattons ones a try.

[Fishmanoz]

Hi WD, I agree with RAF and your suggestion that a decoder with less thsn 1 Amp continuous output to the motor will not do the job.  You don't need to worry about function output current at this stage. Many decoders only provide 100mA per function and this is more then enough for most things such as lights that are run from these.

[john_turner2]

I've used the Hattons (DCC Concepts) 1.1 amp decoders for all my fleet of split chassis Bachmann locos without problem. The small, thin type are very small and can be fitted into a shallow recess in the top of the chassis, easily cut out with a hacksaw and file. Just make sure those plastic axles and gears ate sound because Bachmann were short on replacements!

[The son of Triangman]

Split chassis locos, conversion easy. However they can be an absolute nightmare to put back together after conversion. It is worth making a jig to hold all those pegs with the square bases in place, the things have a habit of dropping out as you do the chassis up, or the little insulating washers that insulated the two halves drop out.  A jig is a good idea.

The split chassis J39 is awful to convert as space in the body is very limited, a micro decoder is usually required, usually one that can handle a continiuous 1Amp stall current. A standard decoder can be fitted in the body but requires some metal to be removed from the chassis. The metal used for the chassis is as hard as diamond and will blunt hacksaw blades, shatter discs used with the likes of mini electric hobby drills, I've DCC'd quite a few split chassis locos for people over the years.

The plastic that makes up the pins holding the chassis together crumbles with age and replacements are usually only now found s/h. The split chassis locos also suffer from crumbling axles and cracking to the plastic of the axles.