Wiring diagram for 8 pin adpater to non DCC ready Loco

[Deem]

I have bought used Hornby Duchess of Sutherland with can motor Loco driven with pick-ups from tender.

Previous owner had hard wired LaisDCC decoder. Loco needed full service, going to wheels bearing to be cleaned so wheels could run freely. I tested the motor out of the chassis it was using 0.5 mA to 0.6 mA, I knew motor is fine and running nicely so I focused on the wheels and found that middle wheel bearing was sticky with old grease, cleaned it with cloth and oiled all the wheel bearing with drop of oil and all seem to be running fine after that, when I fitted every thing I notice that Loco is running on half throttle at 0.8 mA to 0.9 mA. At full throttle Loco is using tad over 1.0 amp. I think after fair usage and everything settled in the chassis this will come down significantly. These reading are from direct power to motor in DC mode.

My question is

I want to install 8 pin adapter so if I need to use this in dc mode I can just insert 8 pin blanking plug or If I decided to use this in DCC mode I can just insert Decoder. Please if I can have wiring diagram as where to install red and black wire from 8 pin adapter so loco can run without tender and when tender attached it gives extra contact. Obviously orange and grey wires go to Motor which I have already soldered correctly to make sure wheels spinning in correct direction as per the controller switch.

Tricky part is Loco only have one wire coming from Loco chassis unlike other Loco I have seen which usually have 2 wires coming from chassis to 8 pin adapter.

Can I isolate the pick ups and solder extra wire to one side of the pick ups or would that cause problem.

Hornby Service sheet HSS 223e is the closest I can see which looks like is the correct service sheet for my Loco.

[ColinB]

You can do this two ways, either use the existing wire for one side and use the wire that should be attached to the motor cover screw as the black wire, or you can add wires to the pickups. Yes, you can attach wires to the pickups I have done it to all of mine. When you take the pickup plastic plate off you find there are no wires going to the pickups but an eyelet that connects to it. I remove the eyelet and wire thin wires to both pickups. What I also do is buy a later tender base and move the DCC socket to the tender. Lendons has the later tender bottoms (X7585) complete with weight and socket for not much more than what a socket will cost you.

[Deem]

Thanks for fast response to my query ColinB.

I will have to try wiring as you suggested, in couple of days because I am busy. As for your suggestion that later tender Bottom, will that take the wheels and body shell from existing tender, or do I need to buy these as well.

Regards

[Fishmanoz]

Take a look at an 8-pin socket here on Brian Lambert

https://www.brian-lambert.co.uk/DCC_Page_1.html#Bookmark11

[96RAF]

Some DC locos as Colin said have one side pickups attached to a wire going to the motor and the other pickup bears on a stud and uses the metal chassis as its wire. The other motor brush attaches to the chassis by way of a ring tag usually at the front motor mount screw.

Using the later lower chassis and pickups gives you two pickup wires to take to a DCC socket, then you can forget about the motor mount wire.

Or as Colin says you can go for a tender location for your DCC socket, wiring loco to tender through a four pin plug and socket.

[ColinB]

The replacement tender bottom comes with wheels but the old ones will fit anyway. The tender should fit if is attached by the one screw at the front, I don't think Hornby ever made a Railroad version of this model, so all the loco driven tenders attach the same.

[ColinB]

I forgot to mention, when you attach the two wires to the pickups file down the circular lug that used to connect the chassis to the pickup. Leave about about 1 to 2 mm as it helps to locate the pickup plate.

[ColinB]

I forgot to mention, when you attach the two wires to the pickups file down the circular lug that used to connect the chassis to the pickup. Leave about about 1 to 2 mm as it helps to locate the pickup plate.

[Deem]

Thanks ColinB and 96RAF for your help.

I will order the Tender bottom from Cardiff of Lendons.

Regards

[LMSFan72]

Another option is to enable DC running on the decoder. Then you don’t need to install or remove anything. You could have it enables all the time or just change the value when you need. It’s done by changing the value of CV29 - either add 4 if not enabled) or remove 4 (if enabled) to switch it

[96RAF]

Another option is to enable DC running on the decoder. Then you don’t need to install or remove anything. You could have it enables all the time or just change the value when you need. It’s done by changing the value of CV29 - either add 4 if not enabled) or remove 4 (if enabled) to switch it

 

 

The problem with enabling DC running is the loco can be prone to DC runaway on a DCC track. This can happen when the decoder loses the DCC signal, drops into DC mode and sees the DCC rail voltage as max throttle whereupon it races off out of control.

In addition it is almost impossible to get reliable DC running as the decoder first has to have the track voltage above a certain minimum to get the decoder to boot, then it has to decide it is on DC and switch to that mode. As soon as you turn your DC controller below the boot threshold voltage the decoder drops out and at next throttle up the process starts again.

DC running can be useful for steady state running such as when running in a loco, but not for much else.

[Deem]

Thanks everyone for taking time and sharing your idea's and thoughts.

Really Appreciate all the help.

Next question

(I hope I am in the correct forum for this question)

I have running loco on/off on rolling road for around !0 minutes in total. Loco still taking on average 1.0 A - 0.9 A, so I am reluctant to test this Loco in DCC mode with decoder installed.

Any idea's as why Loco is using this much, specially when I checked the motor without any load, motor was using 0.5 to 0.6 A with multi meter. At one point loco was using 1.2 to 1.1 but it is not going down below 0.9 A.

Regards

[Fishmanoz]

Definitely something wrong at that current. What type of motor - Ringfield, X03/04 or similar, modern can?

Assuming you’ve serviced it and running freely through the drive train to the wheels, most likely on older motor will be weak magnets. There seem to be people around running a remagnetising service.

And yes, better posted separately in the General forum, lots of motor servicing knowledge there.

In fact, start by reading the excellent FAQ1 in the index in General. LC is pretty much the most experienced contributor in the last 10+ years.

[ColinB]

For a start all your units are wrong 1.0 mAh 0.9 mAh, you obviously didn't mean that 1.0mAh, so what is it in amps or milliamps. Your units read as milliamps per hour (mAh) which is not a unit I recognise. Normally we rate batteries as ampere hours. Sorry but I have to question as to whether you are measuring the right thing. If your motor was drawing an amp it would get extremely hot, especially if it was a can motor.

[Deem]

Maybe i am not explaining correctly and for that I apologise.

I will ask this question tomorrow in general forum.

As for what kind of motor, it's can motor and draw 0.5 to 0.6 amp alone with direct power to motor when I have the meter set to 200m in amperage section with red cable in amp connector.

Motor is never hot, warm maybe but not hot at all.

As for 1.1 or 0.9 amp, I thought maybe that's mA but I must be wrong and it just an amp or below amp.

Apologies ColinB for confusion.

[ColinB]

In that case avoid the Hornby decoders they are only rated at 0.5 amps, you can get a Zimo 8 pin off YouChoos that will source 0.8 amps, currently that is the only one that is in stock. They currently are £24 + P &P. I use these for all my Duchess locos and they work perfectly. They are also a lot more robust as long as you don't accidentally connect DCC input to the motor outputs. The ESU non sound decoders are also ok. Avoid DCC concepts or Gaugemaster in my experience these have issues with the higher currents. if you do want to replace the motor I found Royal Scot ones fit, I think you can still get them and they are cheaper that the one recommended for a Duchess, which you currently cannot get.

[Deem]

Thanks ColinB

Appreciate your help, may I ask what is part number for the Royal Scot Motor, only if you know by any chance.

Regards

[Going Spare]

ColinB may be able to provide additional information but from Service Sheets, it appears the motor is X7218 which was fitted to Royal Scots from 2017. All Princess Coronations, and Royal Scots released prior to 2017, used the X4026 motor. Unfortunately X7218 seems to be unavailable from Hornby and the main spares suppliers.

[Deem]

X4026 is available from Lendons of Cardiff.

RDS Mod Note: Attached picture removed from this post. I don't think we need to repeat other companies web pages on here.

[Deem]

Thanks Going spare.

You are correct X7218 is not available but X4026 is available from Lendons of Cardiff for £29.99 plus postage.

Regards

[Deem]

I have quite busy for few days hence no progress to report.

Just updating what I have with pictures.

Regards

[Deem]

[96RAF]

You need the dial set to 10amps not 200mA.

Also it is difficult to create a stall on a rolling road, so what you are seeing is a free running value which seems very high for a can motor.

[Deem]

I have changed to 10A and I am getting reading of 0.12amp. Both directions. please see pictures.

[Rog RJ]

0.12 Amps. The same as 120 mA (120 milliamps). A reasonable current for a model on a rolling road.