HM7K - A Solution for fitting into a Hornby BR Stanier 2-6-4T 4P. (R2636)

[Pendragon Sailing]

Just thought I’d post this in order to perhaps be a help others who might be experiencing the same problem.

Owners of this particular version of the BR Stanier 2-6-4T (R2636) might be aware that the original wheel pickup configuration left something to be desired, while the left pick-up uses the usual wire connection straight to the PCB, the right hand pickup however use contact with the chassis as a means of transferring power to the motor, with the right-hand pickups themselves relying on contact with a single metal lug on the under-frame, which often creates an intermittent connection as the loco move over points, curves or uneven track.
When I tried installing a HM7K decoder (8 pin), this intermittent contact, as you’d expect, played havoc with the bluetooth signal, with the inevitable result of constant resetting.

I investigated this issue and discovered that the latest replacement Chassis Bottom Set (Hornby part No.X9182) has now more sensibly been furnished with two wires, for direct wiring to the PCB. I duly order up this spare (£4.95 from New Modellers Shop) and set about fitting it. The only small adjustment needed was to grind away the aforementioned contact lug from the chassis base, and then soldering the two track-feed wires directly to the PCB. 

Loco now works perfectly on Bluetooth, with no cut-outs or hesitation in running. 😃👍🏼

[ColinB]

5 minutes ago, Pendragon Sailing said:

Just thought I’d post this in order to perhaps be a help others who might be experiencing the same problem.

Owners of this particular version of the BR Stanier 2-6-4T (R2636) might be aware that the original wheel pickup configuration left something to be desired, while the left pick-up uses the usual wire connection straight to the PCB, the right hand pickup however use contact with the chassis as a means of transferring power to the motor, with the right-hand pickups themselves relying on contact with a single metal lug on the under-frame, which often creates an intermittent connection as the loco move over points, curves or uneven track.
When I tried installing a HM7K decoder (8 pin), this intermittent contact, as you’d expect, played havoc with the bluetooth signal, with the inevitable result of constant resetting.

I investigated this issue and discovered that the latest replacement Chassis Bottom Set (Hornby part No.X9182) has now more sensibly been furnished with two wires, for direct wiring to the PCB. I duly order up this spare (£4.95 from New Modellers Shop) and set about fitting it. The only small adjustment needed was to grind away the aforementioned contact lug from the chassis base, and then soldering the two track-feed wires directly to the PCB. 

Loco now works perfectly on Bluetooth, with no cut-outs or hesitation in running. 😃👍🏼

You can just add your own extra wire to the existing pickups and also delete the stud connection for the other pickup. I do it to all my locos when I convert them to DCC. Sometimes it helps to leave a bit of the lug as it helps with locating the bottom plate. I must admit I never realised the old system was that bad.

[Pendragon Sailing]

Indeed, Colin, that would work also……..I my case, for the sake of a £5 outlay for the replacement part, I went ahead with the full re-fit. I’d bought the loco 2nd hand, and the existing base plate and its wipers was a little chewed up.

[ColinB]

35 minutes ago, Pendragon Sailing said:

Indeed, Colin, that would work also……..I my case, for the sake of a £5 outlay for the replacement part, I went ahead with the full re-fit. I’d bought the loco 2nd hand, and the existing base plate and its wipers was a little chewed up.

I am not criticising I did the same with a couple of my ones when the parts became available but amazingly on a lot of replacement parts I buy for other locos they still have the same arrangement. I can't remember which loco it was but the latest part still had that old arrangement. You see a lot of Hornby Stanier Tank locos for sale secondhand as poor runners and you do wonder if this is the cause. The rest of the loco is Hornby standard, gears and motor are as per Merchant Navy, Duchess and A1/A4 so there isn't that much to go wrong although I have had issues with the valve gear.

[Pendragon Sailing]

I think you’re absolutely right, Colin.  
Reading comments about this party loco on other Forums would suggest that this poor running things is quite common and that the track pick-up configuration is largely to blame for this. I assume that Hornby addressed this in later versions of the model (?), and thus the availability of the spare part with the two wires, rather than the original set-up with one wire and the chassis connection.

Anyway, my loco is now running and behaving perfectly on HM7K. 

[ColinB]

4 hours ago, Pendragon Sailing said:

I think you’re absolutely right, Colin.  
Reading comments about this party loco on other Forums would suggest that this poor running things is quite common and that the track pick-up configuration is largely to blame for this. I assume that Hornby addressed this in later versions of the model (?), and thus the availability of the spare part with the two wires, rather than the original set-up with one wire and the chassis connection.

Anyway, my loco is now running and behaving perfectly on HM7K. 

The parts only became available about a month ago. Hornby has just released the loco again and to my horror that was the only part they changed (I had one on pre order ages ago, thinking they would modernise it). I suppose these were the parts they had left over. I know because I had one with broken pickups that weren't available as spares for years.