Adding DCC to my gner class 91

[Hipwell]

Hi guys. 

I've got a Hornby class 91 GNER from 1999 (assuming 1999 as that's the date on the bottom of the controller in the kit)

 

It's in immaculate condition, and I want to fit a DCC chip to it. 

I spoke to a gentleman today who basically said that it's a no go as the pickups and rongfield motor don't get along with DCC and it would run worse than on analogue due to the pickups not been able to supply a good contact. 

My 91 runs amazing, it's got contacts on the front and rear bogies although on the front, 2 of the wheels on one side have traction tyres, which is odd, I thought it would make more sense to put them on opposite sides so at least 2 of the 4 front wheels would be getting contact.

 

So basically my question is, am I wasting my time adding a DCC chip to It? Will it run worse than it does now?

[Chrissaf]

Whilst you wait for a reply, perhaps you would spend a few minutes reviewing the TIPs in the TIP page link below:

 

TIP: As a newbie poster on the forum, just be aware that the 'Blue Button with the White Arrow' is not a 'Reply to this post' button. If you want to reply to any of the posts, scroll down and write your reply in the reply text box at the bottom of the page and click the Green 'Reply' button.

 

See also – further TIPs on how to get the best user experience from this forum.

https://www.hornby.com/uk-en/forum/tips-on-using-the-forum/

 

[Augustus Caesar]

@Hipwell

 

Check this video out on YouTube where the guy explains how he did the job with his Inter City version of this loco.

The wiring is essentially the same for these and I did mine a couple of years back (QEII version) and was to video it but didn't in the end. Take note of the isolation of the metal screw/s you have to do when adding a decoder. Do not test its operation until the isolation is done correctly.

The guy doesn't show his physical efforts but does describe the wiring and potential damage you can cause by not isolating the two sides of the motor from each other.

The video should give you a decent idea of what to do.

 

 

The video will open on a new tab so you don't lose your place in the forum.

Read the text he includes as he gives a link for the nylon screws you will need to do the isolation.

[Hipwell]

Thanks alot.

 

Yes I've seen that link on YouTube a couple of time so I know what to expect, but i think what I'm asking is will it run like a bag of rubbish by fitting the DCC?

[96RAF]

How to runs on DCC will depend a lot upon which decoder you fit. You need one that will handle ringfield motor current draw. It is recommended you carry out a stall current check to match against the decoder spec.

 

The reason for having traction tyres on one side only is the current path goes like this...

Depending upon which way round the motor is fitted in the bogie...

Front bogie pickup left side pickup connects direct to motor right hand brush. Some models have pickup from both sides of the front bogie and you can often use later parts to improve pickup on earlier models.

Motor bogie right hand wheels connect through their axles to the motor housing thence directly via a longish metal screw to the left hand motor brush. It is this live path to the motor brush that must be interupted by use of a plastic screw when converting to DCC.

In the event of both sides picking up on the front bogie, then the right side pickup wire will connect to the motor housing.

Motor bogie left hand wheels with traction tyres are insulated from the axle, hence why they are both found on the same side and they have no pickups.

[ColinB]

The guy that told you that is talking rubbish. If done properly it will run on DCC as well as it will run on DC. As you say it has pickups on the back bogie, which is the most important part. The decoder makes a huge difference and I suggest that you get one that has a higher current limit than a Hornby one. Not that I have any shares in the company but I have found that Zimo ones seem to work very well with Ringfield motors and believe me I have tried very many different makes. I converted my 1980s HST and it runs well, the only issue I have is the pickups which are not as good as some modern locos. RAF96 is right is his analysis, your Ringfield motor is going to have diffuculty picking up current on the traction tyre side of the bogie, but that is no different to DC, and I have found that it will on bends and points where the flanges touch the tracks. It sounds like yours is one of the last Ringfields so I suspect it is a 5 pole one so it will run really well. It annoys me when these "so called" experts say things like this, but then it proves they know very little. I have converted about 20 of my old locos and yes they don't run as well as my modern ones, but that is not because of the motor more to do with their design (tender driven locos). Hornby have learnt a lot in 20 years.

As for the traction tyres being only on one side it because Hornby originally made a geared wheel for traction tyres so they could only fit them to one side. I suspect your model has the wheels where you remove the gear so they could have done as you say, but I have a class 66 from 2016 with traction tyres and they were still fitting them to only one side. I have noticed on the newer class 66 bogies they have put them on alternate sides. 

[Hipwell]

Thanks Colinwhat decoder would you reccomend? I gave it a try last night using a Hornby 8 pin decoder just to see if I was capable of getting the wiring right!

 

It runs, but it's about half the speed it used to be on analogue, assuming because the decoder hasn't got a high enough current rating? 

 

Also, the other issue which has not cropped up is that I have to give the logo a small nudge to get it going which is odd, as on analogue it used to run like a dream and never needed assistance getting started. I can only assume this could be because I disturbed the brushes on the motor when isolating those screws? 

 

 

[ColinB]

I use Zimo MX600R, it is virtually the same price as Hornby (if you ignore the normal Hornby discount). I also found that the Zimo seems to handle dirty track better. I am surprised it even works with a Hornby decoder, mine tended to blow up. I suspect you have the 5 pole motor, which is probably why. 

I don't know if you used a socket, but if you did take out the decoder put in a DC header and see if the loco still works as well, that will prove that you didn't disturb anything doing the conversion. That is generally one of the first tests I do when I do a conversion.

[96RAF]

It may be that you need to adjust CV2 V-start to give it a kick. Check your chosen decoder spec to make sure this CV is supported.

[Hipwell]

Sorted it. 

I think I had trapped one of the springs which push the brushes in, removed those and refitted best I could (need to order some new springs are they are distorted from being trapped) and it runs like a dream now! Over the moon with it!

 

I just need to tidy the wiring now as it all looks a bit thrown in. The wires are so dam thin though, very easy to snap them.