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Mainline J72 loco for DCC help please


mckinnell

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Hi all,

 

Can any one PLEASE give me some advice on the best way to safely convert the Mainline J72 loco from DC to DCC, i have looked at one site that outline a way but, am sorry to say the directions are very disjointed to me, and, have politely

 

ask the person responsible form the outlined advice if they could clarify the directions they had set out; no response from the person who has posted the direction has alas not been forth coming in answering my question.

 

This Mainline loco J72 is as

 

new, and, as such is a sweet little model and just BEGGING to being DCC converted and will make a worthy loco for my system, also, can get another two J72 as same for similar price...£32 inc P&P, not bad aye?????.....

 

 

My grateful thanks and regards

 

to all for any advice/ help..

 

 

Tom.....................

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Hi Tom, if we first look at basic principles for decoder fitting, I think it will become clear. First, you separate the pickup wiring and chassis from the motor connections. Then you wire pickups to decoder red and black, and the now isolated motor connections

 

to decoder grey and orange. Job done.

 

If you now take a look at this link http://www.rmweb.co.uk/community/index.php?/topic/15582-mainline-j72/ this is how it's done. You can see that for DC! The pickup connectors and the brush connectors are joined

 

by the one plate. These have to be isolated and the poster has described how he has cut them and fitted plastic to do the job.

 

Can you follow now?

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Fishmanoz said:

Hi Tom, if we first look at basic principles for decoder fitting, I think it will become clear. First, you separate the pickup wiring and chassis from the motor connections. Then you wire pickups to decoder red and black,

and the now isolated motor connections to decoder grey and orange. Job done.

If you now take a look at this link http://www.rmweb.co.uk/community/index.php?/topic/15582-mainline-j72/ this is how it's done. You can see that for DC! The pickup connectors

and the brush connectors are joined by the one plate. These have to be isolated and the poster has described how he has cut them and fitted plastic to do the job.

Can you follow now?
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Whilst the old Mainline J72 is a nice model they can be very bad runners and difficult to convert to DCC because of their split chassis construction. Be absolutely sure they are perfect runners before converting them. The other point to look out for is

 

the fact that the wheels go out of quarter due to the fact that a nylon axle is fitted into a metal stub on the back of the wheels, and these work loose over a period of time and cause the wheels to go out of quarter. All Mainline steam outline models suffer

 

from this.

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Fishmanoz,

 

Thanks for the reply, yes, i have read this information, but alas, these is the directions that appear very disjointed to me as so:-

 

"To fit chip I removed from each long brush retaining plate, cut off the end that the screw goes

 

through"

 

It really does not flow, hence, disjointed to me, i am 60 now, that may be the problem, ha ha ha ha; if you are game, perhaps you might rephrase what he is saying in a way i would find easier to adsorb and would be very very grateful to you

 

for doing so, BTW, am gfoing to purchase the Hornby elink system as, i have read so many many good and glowing reports on this system and, seeing as the alternative is the expensive RR&C0 or Itrains?, it will suit me for my needs, as long as i can get the

 

J72 chipping sorted that is lol lol lol......

 

 

My very best and regards my friend...........Tom......

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Tom, there is a lot more info out there. Take a look at http://www.mrol.com.au/Articles/DCC/SplitChassis.aspx or just google split chassis DCC where I found this link and a number of others including a YouTube video.

 

I had hoped that my original

 

link plus the fact they you had to cut the connection between the chassis and motor connection/brush holder would be enough for you to figure it, but I'm sure those other sources will give you enough.

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The words that bring dread to every professional DCC fitter....Split Chassis....shudder!

 

To be fair some are reasonably easy to fit with a decoder, others are absolute pigs to fit. Most require metal removing in places from the chassis and the metal

 

is very hard to work on, a few are are much easier. Avoid them if you can.

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The models in the photo show both types, the first type being the easiest to fit. The second type of split chassis can be a pig to fit, the model in the photo has had it's motor contacts draged towards the back with 1mm airpace between each side of the

 

contact and the chassis casting. I would have insulated these contacts to be sure of them. Also not all of these chassis lend themselves to having the motor contacts moved in such a way, some have short contacts that touch two springs inside the chassis, this

 

sort need metal removing to do a proper job.

 

Then there's the spacer and washer problem. The chassis are held together by screws, and round pegs with a square plastic plate on the them and a washer fits between the chassis sections with the peg shaft

 

passing through the washer. The screws and pegs sit deep in holes. The washers and pegs have a nasty habit of falling out when you try to put the thing back together. It's can be very frustrating, some of the split chassis models co-operate and fit back together

 

easy, others put of a fight. I usually make a jig that will hold the pegs into place whilst I do the screws up.

 

The chassis pegs also suffer from the dreaded plastic fatigue over time as well and you can sometimes find the screw just spins in it's hole

 

and doesn't do up, I'm fortunate as I bought a pile of the pegs when they were available.

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As has been said, make sure your J72 loco is a perfect runner if making DCC, it will show up any little fault. Also as has been pointed out it's not just the chassis pegs that hold the chassis together that suffer from plastic fatigue. Split chassis wheelsets

 

suffer from cracking and breakage, there are two white collars attached to the wheels one has a square hold the other a square metal peg these fit together to form the axle and commonly suffer from cracking and age fatigue. The split chassis B1's suffer from

 

the plastic distorting and "bubbling" that forms the spokes on the wheelsets, giving rise to distorted wheelsets. All in all, good in their day but not so good today and best avoided.

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