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Author Topic: Fitting DCC to Union Mills 2F  (Read 409 times)

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Online doug22150

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Fitting DCC to Union Mills 2F
« on: November 25, 2019, 04:52:42 PM »
My first attempt at installing DCC in a Union Mills loco.  The Zimo MX616 is so small that it can conveniently overhang the rear worm drive, suspended from the can motor housing.  This meant that there was no need for milling out the inside of the tender, or the alternative of cutting through and removing the "coal" part of the tender casting.  The installation tested perfectly but the loco. does run far more noisily than it did under DC.  Presumably, this reflects the type of motor used.  I think that spending time changing CVs is going to be necessary and it's been suggested that I begin with CV56.  Hopefully, I'll be able to find a setting that reduces the noise level back to no more that it was running under DC!

Offline exmouthcraig

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Re: Fitting DCC to Union Mills 2F
« Reply #1 on: November 25, 2019, 05:34:52 PM »
I have to tackle this task on my 2 UM 700s Doug, and as all my other chips are Zimo 616/617 I am to use the same on this.

Interesting about the noise, I'm no DCC wizard or indeed audio technician but do you think the worm might be amplified by the chip sitting over the top like it is????

I'm hoping you can resolve the issues for yourself but selfishly that you'll let us know so I dont end up with the same mission!!!


Offline Snowwolflair

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Re: Fitting DCC to Union Mills 2F
« Reply #2 on: November 25, 2019, 05:45:48 PM »
If you cut out the fake coal which is about 4mm thick there is enough room for a Zimo sound chip and a speaker above the motor.  You can then create a paper cover and glue coal to it.

Online doug22150

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Re: Fitting DCC to Union Mills 2F
« Reply #3 on: November 25, 2019, 06:06:13 PM »
Thanks for those suggestions.  Unfortunately, the loco./tender drive makes the same noise with the tender top removed!  I initially thought much the same myself, wondering whether the decoder was being pushed down when the tender body was replaced, just making contact with the worm.  That's definitely not the case.   

I do have several DCC sound fitted locos. but this model is so noisy at present it's putting me off putting sound in a Union Mills model!  I have one of their T9s with a professionally installed decoder but that's also pretty noisy, especially at low speed.

I have the latest Union Mills release of the 700, 395 and LMS 2P.  Interestingly, all of those have a thinner "coal" load/  The inside of the tender top looks almost as if it's been milled away, probably creating enough space for a Zimi or Silver Mini. on top of the motor.

Online doug22150

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Re: Fitting DCC to Union Mills 2F
« Reply #4 on: November 30, 2019, 08:52:07 PM »
This conversion is proving to be hard work.  Since my last post on the topic, I've converted 2 more, new, Union Mills models to DCC (using my preferred Zimo 616 decoders) and they run perfectly with no need to adjust CVs.  The 2F, though, is a different kettle of fish!  After several days of remaking connections, the loco. now runs under DCC but it stops intermittently.  One of the driving wheelsets seem to be defective in that it only intermittently conducts current.  If I check with a multimeter, current only passes to the chassis block if I push down hard with the probe so that the inside of the wheel makes contact with the side of the chassis block! But that still leaves 2 axles reliably making contact.

Although the loco. runs under DCC, when I use my Programme Track, the display on my Powercab tells me that the CVs can't be read! does this suggest that the Decoder is defective, although I really don't understand why, if I am still able to make the loco. move using DCC power!

Any suggestions welcome!

 

Offline lil chris

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Re: Fitting DCC to Union Mills 2F
« Reply #5 on: November 30, 2019, 09:56:18 PM »
I have converted a 3f to DCC with a CT DCX77 and apart from struggling setting the chip up it now runs lovely with excellant slow running. I used JMRI Decoder pro to set the loco up, it still took a while, Colin from Union Mills actually sent me a new motor and a resistor when I first tried to get it working.If your having problems with the motor perhaps give him a ring I am certain he will try to help.
Lil Chris
My new layout here, Irwell Valley Railway. https://www.ngaugeforum.co.uk/SMFN/index.php?topic=47127.0

my old layout was East Lancashire Lines.

Offline Izzy

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Re: Fitting DCC to Union Mills 2F
« Reply #6 on: November 30, 2019, 10:26:39 PM »

Although the loco. runs under DCC, when I use my Programme Track, the display on my Powercab tells me that the CVs can't be read! does this suggest that the Decoder is defective, although I really don't understand why, if I am still able to make the loco. move using DCC power!

Any suggestions welcome!

This all suggests pickup just isn’t good enough as programme track output is very low to protect the decoder, while full DCC output can get through, obviously with some struggle.

For reducing the motor noise I would suggest trying the basic coreless motor settings which I have found useful for a range of motors.

These are cv9 = 51 & cv56 = 133.

Izzy






Online doug22150

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Re: Fitting DCC to Union Mills 2F
« Reply #7 on: December 01, 2019, 12:39:13 AM »
Thanks for those further suggestions.  I have emailed Colin at Union Mills to ask about spares. I'm not sure whether his new motor can be used to replace the previous version. 

That's a very good point about poor pick-up: it ties in with the random stopping, although I have thoroughly cleaned all bearing surfaces.  Running my Farish locos over the same length of track, even at a crawl, running is faultless.  Are Union Mills motors coreless or just regular can motors?

Online doug22150

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Re: Fitting DCC to Union Mills 2F
« Reply #8 on: December 01, 2019, 12:30:11 PM »
I tried the loco again this morning.  When placed on the programme track, "cannot read CV" displayed.  I then disconnected loco. and tender, held the tender to loco. connecting wire onto the right hand track and was immediately able to read/alter CVs!  I then dismantled the loco. again, cleaned all bearing surfaces and connected a temporary trailing wire from the small socket below the cab.  When loco. placed on track and tested with a multi-meter, right hand track to end of trailing lead, connectivity seemed fine.

I then reassembled the loco./tender and placed on the programme track again.  This time, I was able to read/alter CVs.  So far so good.  However, I then tried the loco. around my main layout circuit but the problems started again.  I.e. intermittent, random stopping.  It just about completed one circuit but only if I ran at a speed step above 40.  I then put the loco. back on the programme track and again could not read the CVs!  I removed the loco. from the track and put it upside down in a servicing cradle.  This time, when I tested each dirving wheel set for electrical continuity with the drawbar screw (which also holds the loco. - tender wire in place) there was an open circuit between the rear driving wheel set, but the 2 leading axles were fine.  When I had tested this before reassembling the loco., all 3 axles were properly connected.

I can only assume that the rear driving wheelset is defective and for some reason only intermittently transfers power correctly to the chassis block.  I can't really understand that, as the wheel must be pressed onto the axle and it doesn't appear at all loose.  But, the loco. would still be picking up current through the other two driving wheelsets so surely he loco. shouldn't just stop, as it does?  I also suspect that the motor must also be defective in some way.

Offline ntpntpntp

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Re: Fitting DCC to Union Mills 2F
« Reply #9 on: December 01, 2019, 12:51:32 PM »
For the loco to be stalling/stuttering implies total loss of power through all pickups, not just the rear wheelset.   Check the loco is sitting flat and squarely on the track - better still, on a sheet of glass.   

Also check the wire to the tender is not damaged and is gripping securely under the the rear screw - it might need cleaning and tinning?  When I acquired a bargain non-running UM B12 a couple of years ago, the only problem was that wire had come loose and would not grip until I tinned it.

Have you cleaned the tender axle bearings as well as the loco's? I also found that the tiniest drop of Powerlube on the loco axle bearings helped.
Nick.   2016 celebrating the 20th anniversary of "Königshafen" exhibition layout!

Online Dr Al

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Re: Fitting DCC to Union Mills 2F
« Reply #10 on: December 01, 2019, 06:30:22 PM »
If stuttering and stalling, clean the axle slots on loco and tender and also check the central tender wheelset is in the correct way - if inverted it would semi-short things out - it should have insulator on same side as traction tyred outer wheels.

As Nick said, the other suspect is the loco connection wire.

Highly unlikely to be motor or wheelset that you suspect - sounds a straight pickup issue.

Cheers,
Alan
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If Dr Al is online he may be able to provide a more comprehensive answer.

“We have also arranged things so that almost no one understands science and technology. This is a prescription for disaster. We might get away with it for a while, but sooner or later this combustible mixture of ignorance and power is going to blow up in our faces.”Dr. Carl Sagan

Online doug22150

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Re: Fitting DCC to Union Mills 2F
« Reply #11 on: December 01, 2019, 07:27:29 PM »
Thanks for those further suggestions.  Tender wheelsets are all correctly installed, I have tinned the end of the loco. to tender wire and also cleaned the tender bearing surfaces.  Thanks for the reassurance, Dr Al about it being unlikely to be a motor problem.  I will dismantle loco. again tomorrow and I am particularly puzzled as to why the rear driving wheelset seems to lose connectivity. 

Offline Izzy

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Re: Fitting DCC to Union Mills 2F
« Reply #12 on: December 01, 2019, 10:07:56 PM »

I have no experience of UM locos so don’t know how the wheels are insulated, but rather than loss of current, which with other wheels collecting should not be an issue, this has all the hallmarks to me of intermittent shorting. Low level enough not to trip the command station or whatever, but would make the decoder loose focus and give the on/off performance. Zimo can resume at the same speed step setting, so seem to stutter with this issue, some others revert back to start levels.

Izzy

Online doug22150

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Re: Fitting DCC to Union Mills 2F
« Reply #13 on: December 01, 2019, 11:39:08 PM »
 Izzy
Thanks, that's an interesting suggestion.  Union Mills locos. have the loco. live to one track and the tender to the other.  I have noticed that there is a lot of free play between the driving wheel axles and the loco. base plate.  This means that the loco. body is able to rock (to my mind excessively) from side to side a lot while the wheels are still firmly on the track.  I guess that this could conceivably result in the tyres/wheel backs of the insulated driving wheelsets touching the inside of the loco. splashers and causing an intermittent short circuit.  I will investigate further tomorrow.

Online doug22150

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Re: Fitting DCC to Union Mills 2F
« Reply #14 on: December 02, 2019, 06:00:24 PM »
It definitely isn't a motor problem, thanks Dr Al.  I've spent most of today stripping loco. down again and reassembling. It is currently running reasonably well although still noisier in reverse than forward.  I began by detaching the tender, putting it on my rolling road and connecting the loco. end of the loco.-tender wire to the right hand rail.  Doing that, there were no problems in programming the decoder or setting the tender going in either direction.  So far so good.

I then turned attention to pick-up from the driving wheels.  Using my multi-meter, the rear driving wheel set still wasn't passing any current to the chassis block.  I removed all wheels from the chassis block and tested the connectivity of each right hand wheel to the axle.  The rear axle seemed completely dead, the leading one o.k. and the middle one intermittent.  I then resorted to carefully scraping the surface of each axle with a sharp blade.  To my amazement, when tested again, the rear axle would pass current and the intermittent middle axle was also improved.  However, when the axles were replaced in the chassis block, the rear one wouldn't pass current again!  It took two more attempts before the reassembled chassis would pass current reliably through each axle.

This still didn't completely overcome the problems.  When I reconnected loco. and tender all went well for a couple of circuits but then the intermittent stopping became an issue again!  I then decided to carefully re-route the black decoder wire to ensure that it was well clear of the leading worm drive whilst still not preventing free movement between loco. and tender on curves.  For the moment, that seems to have done the trick.  I have successfully run the loco. both backwards and forwards and so far, the hesitation/stopping has not reappeared.

Assuming that all is well when I tray again later, I will not look at CV settings to see if anything can be done to quieten running in reverse.  That will take me back to the point at which I began this post some days ago!

 

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