Fitting a decoder to Hornby R9288 0-4-0 Percy

[Art Dent]

A photo-guide to fitting a decoder to Hornby's 'Thomas the Tank Engine' locomotive No.6 'Percy' (R9288)

 

Below is my pictorial guide to hard-wiring a decoder to Hornby's 0-4-0 locomotive 'Percy' 

 

Step 1 - removing the locomotive body.

 

The body of this locomotive is held in place by just four clips, two at the front of the chassis (just behind the cylinders) and two at the rear (just behind the rear axle).

 

To remove the body you need a flat-bladed screwdriver to prise the body away from the chassis at the front.

 

The picture below shows the 'proper' way to remove the body (as explained in the instruction sheet/user guide that accompanies the locomotive).

 

 

I found it best to put the blade of the screwdriver between the top of one of the two front wheels and the body which releases the clip on one side. The other clip is released by 'rocking' the body from side to side.

 

Once the front clips are released, lift the front of the body clear of the chassis which releases the rear clips.

 

The motor together with two suppression capacitors and an inductor can now be seen together with the rather ugly motor retaining clip,

 

 

The wiring is really quite neat.

 

Step 2 - removing the motor.

 

Ease the wires away from the sides and top of the motor and release the spring retaining clip (making a note of its correct orientation FIRST).

 

The online Hornby guide to fitting a decoder to the 0-4-0 chassis says to cut the wires at the motor end and to unsolder the pick-up wires from the pickups.

 

THIS IS UNNECESSARY

 

As can be seen below, the motor, capacitors & inductor and pick-up wires can be removed in one.

 

Step 3 - removing the capacitors and inductor.

 

The two flat, brown capacitors (marked '104' in the picture below) and the inductor (covered in black heat-shrink sleeving on the right) can be cut  from the two black pick-up wires.  I made the cut just about at the motor-end of each pick-up wire (these can be trimmed later if too long).  The large 'flat' grey thing through which the two capacitor leads pass through is just a spacer.

 

 

 

The two capacitors and inductor can now be unsoldered from the two motor terminals and discarded - they are not required for running under DCC.

 

DO NOT unsolder the two black pick-up wires from the pickups!

 

This is best avoided as Percy (in common with the other 'cheap' 0-4-0 locomotives) has a plastic chassis.

 

Step 4 - refitting the motor.

 

Replace the motor back in the chassis (after insulating the motor to avoid any possibility of shorts) in the same orientation as its initial fitting - so that the two motor contacts are uppermost.

 

(the online Hornby guide suggests re-fitting the motor upside-down).

 

DON'T FORGET to replace the motor retaining clip!!

 

The next few pictures show a 'dry run' of wiring the LaisDCC decoder and so neither has the motor casing been insulated nor the motor retaining clip been fitted as this was my 'first attempt' at hard-wiring 'Percy'.

 

You can see the two discarded capacitors and inductor in the background of this picture.

 

 

Step 5 - fitting and testing the decoder.

 

The steps below show the initial fitting and testing of the LaisDCC 860012 NEM651 + 2 stay-alive wires decoder.

 

Step 5a - preparing the decoder

 

Not wanting to cut any wires short at this stage, I planned to 'bundle up' the quite long decoder wires in case the decoder didn't end up in this loco after all.

 

Note how the white and yellow wires have been trimmed to different lengths (to prevent possible short-circuiting).

 

 

The white and yellow wires were then folded back on each other several times and wrapped in heat-shrink to prevent short circuits (which can destroy a decoder)

 

NEVER LEAVE ANY BARE WIRES WHEN FITTING & TESTING A DECODER IF YOU INTEND TO APPLY POWER TO THE DECODER AT ANY STAGE!

 

I have blown up a £100 Zimo sound decoder making just this mistake - the two wires that shorted were the wires that went to the speaker (which wasn't connected at that stage)

 

 

Step 5b - conneting the decoder to the track pickups

 

Solder the red and black wires to the track pickup wires.

 

With the loco facing forward and as viewed from the driver's perspective, RED wire to TRACK RIGHT and BLACK wire to TRACK LEFT

 

 

Step 5c - soldering the decoder wires to the motor.

 

Now solder the orange and grey wires to the motor.  Theoretically, grey and black go on the left (grey to motor left and black to track left) and red and orange on the right (orange to motor right and red to track right), however, if you find your loco goes backwards when the throttle says forwards, simply reverse the motor connections (i.e. orange to motor left and grey to motor right) .

 

 

Step 5d - testing the stay-alives.

 

I initially wired up the stay-alives that I purchased at the same time as the decoder in order to test out their effectiveness.  The small one did very little (save a VERY brief stutter BACKWARDS when track power was removed) whilst the larger stay-alive ran on for a VERY IMPRESSIVE 25 seconds - but at full power and in reverse!

 

The stay-alive wires were therefore not fitted, and the stay-alive decoder wires were isolated as shown here whilst the decoder installation was tested on a programming track and rolling road.

 

 

Step 5e - testing the 'Heath Robinson' wired decoder.

 

The Heath-Robinson wired decoder being tested on the rolling road.  It ain't pretty, but it worked first time ...

 

 

Another view ...

 

 

Step 6 - 'Proper' installation.

 

Motor now insulated with Kapton tape and re-installed in the plastic chassis:

 

 

Notice anything missing - yes, the motor retaining clip!

 

I fabricated a small plastic shelf above worm gear for decoder to sit on and black-tacked it in place:

 

 

Everything wired up (apart from stay-alive).

 

Everything (wires, decoder support and decoder) is black-tacked in place.  So much MORE useful than Blu-tack (i.e. get some)!

 

 

Step 7 - testing the installation.

 

Percy with body re-fitted on the rolling road test track.

 

 

Everything works (for now, fingers crossed).

 

I don't know why but some pictures (most) are HUGE and others are rather smaller.  Can't seem to do anything about it though,

 

Some observations

 

With hindisght (wonderful thing that it is) I would have left the decoder 'free' on the end of the long wires and fed the wiring above the motor (there's lots of room), black-tacking the decoder in the coal bunker.  With the body removed, a small (and easy to release) clip holds the top of the cab and fake coal in place.  Once removed, there is ample space to fit the decoder and a stay-alive under the coal, and the cab roof and coal is then easily clipped back in place.

 

Given that the LaisDCC decoder and its stay-alive behave in such a bizarre fashion (as noted above - see step 5d), I will replace this decoder with a DCC Concepts Zen 218 decoder and one of DCC Concepts own super stay-alives and put this LaisDCC decoder (without the stay-alive) into the all-wheel pickup, 0-6-0 Thomas (R9287).  I feel that Percy - being an 0-4-0 locomotive - will be more prone to stopping when crossing points or at isolated (dirty) parts of the track (and probably in the most inaccessible of places!)

 

I hope that you have found this guide helpful, informative or simply entertaining!,

 

I aim to do a similar illustrated decoder installation guide for Hornby's Thomas R9287 (which, should be a lot simpler!) when the afore-mentioned Zen 218 decoder arrives after Christmas.

 

Merry Christmas and a Happy New Year to all.

 

Art

Edited December 26, 2018 by Art Dent

[RAF96]

I fit NEM 652 sockets rather than hardwire to these little locos. Makes it much easier to swap one out if a decoder fails.

 

 

You can get them for pennies each from China.

Edit - or prewired from various places even in UK.

 

Rob

Edited December 26, 2018 by RAFHAAA96

[Art Dent]

UPDATE 1

 

Okay - so I have taken the LaisDCC decoder out of Percy (it has now gone into Thomas) and fitted the DCC Concepts Zen 218 decoder together with the stay-alive unit supplied with the decoder.

 

The Zen 218 is larger than the LaisDCC decoder and needed putting in the bunker ...

 

 

... with the excess wires (which at this stage hadn't been bundled together and heat-shrink wrapped) lying across the top of the motor ...

 

 

In the final installation these wires are trimmed to slightly different lengths (to prevent the possibility of shorting out) and heat-shrink sleeving applied.  They are then black-tacked to the side of the motor (excellent - and very sticky stufff, black tack - highly recommended).

 

These two pictures show that there is enough room in the bunker to fit both the Zen 218 decoder and the supplied stay-alive:

 

 

and

 

 

Whether fitting this stay-alive is worthwhile (in terms of both finding the space and also ensuring that the wires are secured properly) in your own locomotives is moot as I can discern no noticeable effect!

 

Even putting the loco on a rolling road on my test track (which has a switch to kill power to the track instantly) and killing the power after leaving the loco running  at medium speed for 5 minutes makes the wheels stop virtually instantly.  If it has ANY effect at all, it is probably around 1/50th second.

 

So, I'm looking to fabricate a medium-sized stay-alive unit of my own and to this effect have sourced some 47000uF / 47mF / 0.047F, 5.5V super-capacitors which measure 10.9mm x 10.4mm x 5.1mm (h x w x d excluding leads).

 

 

I'm planning to wire these up tomorrow and see what happens.

 

Being 5.5V I am going to use just 3 in series to give a voltage of 16.5V (to use on my NCE PowerCab system which puts out 13.5V rectified DC) and a total capacity of 15700uF /15.7 mF / 0.0157F.

 

Watch this space!

 

Art

Edited January 13, 2019 by Art Dent

[Art Dent]

UPDATE 2

 

Fabrication of the 15.7mF (15700uF) stay-alive unit.

 

This is documented in another thread (link here >> http://www.rmweb.co.uk/community/index.php?/topic/141301-fabrication-of-small-capacity-diy-locomotive-stay-alive/)

 

This update shows the installation of the stay-alive unit in 'Percy.

 

In the above thread, I fabricated this stay-alive unit - maximum voltage is 16.5V and capacity is 15700uF

 

 

Here is the unit in Percy's bunker along with the DCC Concepts Zen 218 decoder - both black tacked in place.

 

 

The unit measures 31.2 mm end to end, just over 12 mm high and around 8 mm at its widest (although most of the unit is 5.2 mm thick).

 

It gives the loco around 1/4 to 1/3rd second of power and a few cm of travel.

 

At around £1.30 to make - significantly cheaper than anything else out there (although I would like around twice the capacity of this in practice).

 

Hope this helps,

 

Art