Installing DCC Now plus Sound at later stage to Non DCC Class 08

[Deem]

Hello to Everyone

If some one can advise me.

I have Hornby Class 08

Service Sheet 139A

Doesn't have DCC fitted and considering to install DCC decoder.

This loco runs very smoothly on DC after I have cleaned and done full service, installed new Traction Tyres and Loco run very good both direction.

I have spare X8809DM motor with 6 Pickups (3 on each side) and 4 pin male wire connector which accept Hornby 4 Wire Decoder (R7274).

My understanding is I can change all wheels with Hornby X8871M so I can all wheel pickups from Track.

Also in future I would like to install TTS sound decoder so how would I add that to Hornby R7274?

I am totally new to DCC so I am asking questions now so I understand before I attempt to install or choose a particular way to keep the cost down.

Any Advice will be much appreciated.

Regards

[Going Spare]

You may not be able to fit the front wheelset from X8871M because your chassis block is set up to take an axle without bearings and if I remember correctly, all the wheelsets in the new pack have bearings. If that is indeed so, I would be tempted to replace only the centre wheelset if you want to do away with tyres. However, the new wheelset will have metric threads to take the coupling rod screws whereas the existing screws have BA threads, so you will also need the coupling rods pack X8877 to give you metric screws. The additional pick-ups should work just as well on the remaining original wheels.

I don't run DCC but the TTS decoders appear to have an 8-pin plug. Your X8809DM motor & housing assembly has a 4-pin socket attached. So to fit an 08 TTS decoder you would have to change the plug & socket but others who run DCC will no doubt come up with any further implications of running a TTS decoder off a 4-lead feed, if it is possible.

[Jim-R855]

I can offer some advice since R861 LNER J52 is on the same service sheet and I have converted mine recently, including replacing the motor with the X8809DM, but only because I broke a tag on the original motor and it was too short to re-solder.

First thing first - you don't add the sound decoder to a simpler decoder, I mean technically you can install several decoders in a model, but the sound decoder will also drive, so just replace the basic one when you upgrade to avoid the complexity of programming 2 decoders (you apparently need to lock each one in turn to program the other). So if you are going to try first with a basic decoder, intend for it to become redundant, or go into the spares box for future use. It is worth trying with a basic decoder, there is a lot to go wrong.

on the plus side as you have noted there should be plenty of room in an 08 body for a sound decoder and speaker.

The chassis is metal (mine is, so I presume yours will be) and at present one set of wheels is isolated and the other conveys current through the chassis. From memory the left wheels go through the chassis (pickups not isolated from chassis, but also any other path is valid) and the right wheels and pickups are isolated with a wire from the pickup tothe motor. When you remove the motor, you will find the left pickups have a strip that runs in under the motor to contact the lower terminal of the motor. This all needs isolating, and just removing those pickups to use the new ones is not enough, you need to physically isolate the motor from brushing against the chassis. I used Kapton tape for this - I have no idea how permanent it will be, but it is very thin and can be carefully cut to fit around recesses and lumps. On my first attempt this was all I did, and I was lucky not to fry a decoder because when I went to try the loco I got a short, and quickly discovered that as the loco moves around (especially if you nudge it) those nicely sprung rear wheels can touch the chassis even though they are isolated at the axle. On closer inspection, all 6 wheels can at extreme motion touch the sides of the chassis, but the sprung ones do it easily. My solution was a complete strip down and apply Kapton tape to the sides of the chassis as well as under the motor. At this point most people would be looking for a later plastic chassis and throwing the metal one away!

Even if you fit a full set of isolated wheels so there is no path from the axles to the chassis, the rims of the wheels can touch the sides of the chassis.

Now having put the original pickups (4 wheels) and motor to one side you try to fit the new one, but it won't sit down properly. On closer inspection the left side of the new plastic housing that carries the left (isolated) pickups is longer than the old one, because originally the pickup was mounted on the chassis and the motor mount was cut away on that side to accommodate this. You can't cut the excess bit off because the pickup is mounted on it and you will damage it trying to remove it, so gingerly at first until you realise it needs quite an effort you will need to pry the old motor out of its mount, then the new one, and put the new one in the original mount (you will need to cut or desolder the top wire to do this). Whislt re-assembling I then bit the bullet and cut off the bit off the original pickup that turns in and under the motor - unfortunately I can't see a sensible way to use those 6 wheel pickups, I just stuck with 4 wheel pickup.

You will need to de-solder red and black from the new pickups and solder onto the old pickups (same sides if you want forward to be forward), and re-solder the top wire onto the motor unless you cut it and just need to join it.

Use a multimeter on resistance mode with the probes on opposite wheels and rock the chassis in all directions and make sure it doesn't read a short at any point. If you successfully isolated everything, you should now have a model ready to install a Hornby 4 pin decoder. What I actually did was cut the 4-pin connector off and solder a standard 8-pin connector on so I could use a decoder with functions to control directional lights and firebox glow (except I temporarily have a 2 function decoded plugged in so no firebox yet) - for a diesel you might want forward and reverse lights and cab lighting if you are feeling enthusiastic for modifying your model with some LEDs too. Many people in a small loco would just solder the decoder wires to the motor and pickups and do away with the socket to save space, I would certainly need to do that to fit a sound decoder in my J52, but there should be plenty of space in an 08 body (my Lima LMS class 11 has loads of space, but it has a ringfield motor up one end so different to a Hornby 08).

As for how it runs, once I got my motor housing seated right so the worm meshed with the drive gear properly, the J52 is incredibly smooth at all speeds under DCC control with only 4 pickups. Admittedly it does have a Zen decoder which has capacitors built in to provide some stay-alive function so you might have more stuttering over points etc. if using a different decoder.

Good luck!

[Jim-R855]

@Going Spare

You may not be able to fit the front wheelset from X8871M because..............

 

 

Good point about the tyres, if OP wants to keep the (new) traction tyres, there is no point adding pickups to the middle wheels...

Probably a sound decoder could be wired with just red and black wires if you just want the sound off if, wiring grey and orange will allow it to drive the motor too. The other 4 (or more) wires are to wire up extra functions such as head lights, cab lights, smoke generator etc. you can cut them off and fit a 4-pin plug if you want to.

[Deem]

@Jim-R855

WOW WOW WOW

Excellent write up and detailed explanation. Many thanks.

Based on your detailed explantation in my opinion I am better off staying with existing motor and isolate or change, to plastic chassis (if I can find one).

Instead of installing Hornby 4 wire Decoder I should wait and save the money to buy Full 8 wire decoder so later I can wire up the speaker and upload sound file to that Decoder if it is possible.

Or Even more expensive option is TTS Sound Decoder with built in sound

[Jim-R855]

I would recommend starting out with a non-sound decoder (8 pin if you are definitely going to install an 8pin socket, there are other interfaces available) which will cost about 25% as much a sound decoder, just in case you miss something in the conversion and get a short that destroys it.

[Deem]

I have just opened both Loco and noticed both Loco have Plastic Chassis, I checked with multimeter as just to make sure. Please see pictures,

[96RAF]

This may help

https://www.newmodellersshop.co.uk/hornby_spares_motors_and_gears.htm

New Modellers shop, scroll down to the Type 7 motor for live links.

This is the bit to look for.

and this is the modifications required to the chassis.

[Going Spare]

Both chassis blocks are solid metal. Only the wheel retaining plate on the bottom is a plastic moulding.

[Deem]

@Going Spare

That's strange but I can't be sure until I am back in my ManCave tonight to check the Chassis.

But I can state that both chassis are identical and if one loco is running fine with Decoder I am assuming older non DCC loco should be able to work with Decoder as easily.

I can't afford to waste money hence the reason I am trying to understand before I commit myself to hard wire the new Decoder on to NON DCC Loco.

Any help will be much much appreciated.

Regards

[Deem]

@96RAF

Thanks for your info, I have 3 spare identical motors of which you added the picture and link from NEW MODELLERS SHOP.

As for the chassis modification, although chassis doesn't have hole with thread for the bracket on the front of the chassis where Decoder holder would fit in, I don't need it because I will be using 8 wire 4 FN decoder which could be place on the chassis with double sided tape or blu tack. or above the motor in Body Shell.

Once I have saved money and received the Decoder I will be adding pictures of installation here.

Thanks again for your help and info.

Regards

[Jim-R855]

Interesting. The old one is definitely a metal chassis, you can see the metal on some corners where the black has worn off.

Does the DCC fitted loco have a sprung rear axle (lower in photo)? I found that the sprung axle was allowing the wheels to touch the metal on the chassis and causing shorts, I also found that when properly gauged it was possible for the front wheels to touch but unlikely, and not possible before I set the back to back distance properly on all axles - maybe I was too fussy about that!

[Deem]

@Jim-R855

Thanks for sharing your experience.

I wouldn't know because I didn't had to open the bottom chassis cover during servicing. I can give it go and try to find out DCC Fitted Loco have sprung rear axle or not.

Regards

[Deem]

@Jim-R855

My mistake, I did open the bottom chassis and did clean the axles, they had dried up grease. Now I can recall after looking the actual underneath bottom chassis cover.

Non of the wheel have sprung axle on this loco, I can confirm that, please see below picture.

According to Service sheet for this Loco HSS308E theren't any sprung axle either. I hope I made it clear who ever is interest or looking for this .

Regards

[Deem]

Another issue I came across today is Bachmann Dynamis Can't read Hornby 4 wire Decoder R7274,

I have Hornby Class 08 with factory fitted 4 wire Decoder which works fine and program everything but I try to read

I get

Error 10

No Read Possible

Anyone can explain or have similar experience please share your thought or opinion.

Regards

[96RAF]

The 4-pin decoder is the same as the R8249 NMRA warranted decoder but with fewer wires attached, so the problem lies with the Dynamis. Try using Reg mode. You will have to look up the use of the registers as there are only 8 of them unlike CVs which are many.

[Deem]

@96RAF

Thanks for your input and will lookup today or tonight.

Regards

[Deem]

I was trying to figure how to read in Reg Mode as per suggestion of RAF96, can't find any info on how to select Reg Mode in Dynamis but came across this,

from

https://www.bachmann.co.uk/dbdocument/1006/ultima%20guide.pdf

and as per this guide Error code's are

Am I to assume Bachmann Dynamis Controller doesn't support Service Track/ Main Track Read because I tried with one at time, both Just Now with error as follow

ON Service Track: Error 10

ON Main Track: Error 9

Regards

[Deem]

Further Update on Bachmann Dynamis Command Station (which different to Bachmann Dynamis Ultima)

I tried to Read decoder on Bachmann 32-042DC Class 20 D8101 BR Green, with same result

On Service Track: Error Code 10

Would not allow me to read on Main track Setting at all.

[96RAF]

In general you cannot read-back on the main track, unless railcom is enabled then read-back is decoder dependant and limited in which data is readable.

I would suggest maybe your service track programming is caput. I take it you are using a dedicated track piece connected to the Programming output.

You could try a controller reset to see if that brings it back into fettle or not.

Unfortunately due to the nature of service track programming there is only a low power short burst of data during programming, too little to read on a meter, although you can capture it on a ‘scope.

Reg Mode..from your reference manual.

[Deem]

@96RAF

Where did you find this page, if you mind sharing with please.

Regards

[96RAF]

In the manual you linked to.

[Deem]

@96RAF

I found the page which you just copy and pasted above and thanks for reading properly instead of asking on forum, like I did. I had the PDF document opened and just went passed the REG MODE activation or various other Options.

Regards

[Deem]

@96RAF

Thanks

I believe we both are looking at the wrong Manual, only either I must have stated that I have Dynamis Ultima or we both assumed it's Ultima Unit.

The manual you have copied from, also I placed the Link for same manual here in the Forum. That manual is for Bachmann Dynamis Ultima (same controller but different base station)

However I have Bachman Dynamis Command Station, same controller as above model but different base station with limited functions)

According to Dynamis Command Station Manual (https://www.bachmanntrains.com/home-usa/ez_content/dynamis_manual.pdf) For reading CV value I need Dynamis ProBox.

Another option is to invest into Sprog, any thoughts?

Regards

[Deem]