westonman Posted April 23, 2013 Share Posted April 23, 2013 Hi all,haven!t been on the forum for a while,can anyone help sort my problem. I have a Bachmann Hall class loco 5927 Guild Hall which has a factory fitted decoder. When running on DC its fine runs smoothly at all speeds. But running on DCC its runs very jerky at slow speed. I have removed the capacitors and replaced the factory fitted decoder with a new Bachmann 8 pin 3 function decoder but this has made no difference,the loco still runs jerkily at low speed. I am using a DCC Powercab controller, have checked the wheels and track are clean and pickup wipers are making good contact with the wheels. I am new to DCC so any help will be appreciated. Regards Bob Link to post Share on other sites More sharing options...
Silver Sidelines Posted April 23, 2013 Share Posted April 23, 2013 Hi Bob, Just a thought - did you run the engine first without the DC chip? No matter you appear to have been back inside the model to add a different chip. I recently acquired a model of Raglan Hall and needed to remove the chip for use with Gaugemaster DS controllers. Raglan Hall ran really smoothly but it had a very pronounced tight spot when stopping and starting. Pretty obvious really, the hole for the water pump spindle in the body needed opening up so that the spindle was a slack fit. It might just be that you have put the body on sightly differently and that the spindle on your model is now binding. Regards Ray Link to post Share on other sites More sharing options...
RMweb Gold RFS Posted April 23, 2013 RMweb Gold Share Posted April 23, 2013 I would suggest you need to adjust the BackEMF values as defined by Bachmann's documentation here - http://www.Bachmann.co.uk/pdfs/decoder_settings.pdf . In particular set CV 54=12 and CV 55=63 for starters, but you many need to adjust these until it runs smoothly. These values are not the default for the decoder, so if the decoder is reset you'll need to enter them again. Link to post Share on other sites More sharing options...
westonman Posted April 23, 2013 Author Share Posted April 23, 2013 Thanks for the reply Ray,but the loco is still the same with the body off Thank you RFS will try altering the CVs have not done this before but will give it a go. Regards Bob Link to post Share on other sites More sharing options...
tender Posted April 23, 2013 Share Posted April 23, 2013 Hi all,haven!t been on the forum for a while,can anyone help sort my problem. I have a Bachmann Hall class loco 5927 Guild Hall which has a factory fitted decoder. When running on DC its fine runs smoothly at all speeds. But running on DCC its runs very jerky at slow speed. I have removed the capacitors and replaced the factory fitted decoder with a new Bachmann 8 pin 3 function decoder but this has made no difference,the loco still runs jerkily at low speed. I am using a DCC Powercab controller, have checked the wheels and track are clean and pickup wipers are making good contact with the wheels. I am new to DCC so any help will be appreciated. Regards Bob My Guild Hall is exactly the same, been playing around with it for over a year to no avail. I did hear that this is sometimes attributed to a crack in the final drive gear when it gets pressed onto the shaft. but having checked mine over it looks ok. Tried several different decoders as well. Looks like the new modified Halls use the same chassis so won't be buying one of them until this gets sorted. Link to post Share on other sites More sharing options...
tender Posted April 23, 2013 Share Posted April 23, 2013 Thanks 81C, will check this out. Link to post Share on other sites More sharing options...
RMweb Gold RFS Posted April 23, 2013 RMweb Gold Share Posted April 23, 2013 (edited) As the OP said on his initial post - When running on DC its fine runs smoothly at all speeds. But running on DCC its runs very jerky at slow speed. Bob Hence his problem must be DCC rather than anything mechanical. Furthermore, the problem is very characteristic of a Bachmann loco with the standard Bachmann decoder - hence the need to adjust CV54/55 as recommended. Alternatively, use a better quality decoder, such as a Lenz Standard+ which will run the loco smoothly straight out of the box. I had several locos like this and eventually replaced the decoder with the Lenz and have never looked back. Edited April 23, 2013 by RFS Link to post Share on other sites More sharing options...
Combe Martin Posted April 23, 2013 Share Posted April 23, 2013 This is a standard problem with the Bachmann decoder. The default values for Back EMF just arn't suitable for their steam locos. They're for diesel locos fitted with much larger motors and/or flywheels. Even Bachmann's own recommended Back EMF CV values are no good, in fact I could be very rude about them. I couldn't get any of my 3 S&D 7Fs to run properly with the Bachmann 21 pin decoder, all ran jittery at slow speed. One now has a Lenz Standard and the other 2 a ZTC258, but I did have to use a 21 to 8 pin adapter, and cut down the mounting posts for the 21 pin socket to lower it. I finally put the Bachmann 21 pin decoder in a 3F, and by setting CV54 to 1 and CV55 to 60 it's not too bad. But of course this loco has very few potential spots in it's mechanism for binding. It's only a 6 coupled, and no valve gear. You could try the same CV values, it won't hurt. Link to post Share on other sites More sharing options...
westonman Posted April 24, 2013 Author Share Posted April 24, 2013 Hi all Have adjusted the CVs, 54 to 1 and 55 to 60 the loco is now running a lot better,have also ordered a Lenz decoder and will see if this makes a difference. Another problem i have with Bachmann decoders is that i cannot enter a long address. It will let me programme a short address ie 2 numbers but when selecting long address ie 4 numbers it will not accept it. I am using an NCE Powercab controller any ideas what the problem is or am i doing something wrong. Regards Bob Link to post Share on other sites More sharing options...
RMweb Gold RFS Posted April 24, 2013 RMweb Gold Share Posted April 24, 2013 (edited) Some versions of the Bachmann decoder do not support 4-digit addresses. At one point I had two Bachmann decoders both of which looked identical: one let me use 4-digit addresses, the other didn't - presumably both identical hardware but different releases of the firmware. You'll have no problem in this respect with the Lenz. Edited April 24, 2013 by RFS Link to post Share on other sites More sharing options...
westonman Posted April 28, 2013 Author Share Posted April 28, 2013 Hi all Re problems with Hall loco on DCC. Fitted a Lenz decoder and it was back to jerky running again,so i have fitted a blanking plug and returned it to DC,it now runs fine. Bob Link to post Share on other sites More sharing options...
Froxfield2012 Posted June 11, 2015 Share Posted June 11, 2015 Hi Bob, Just a thought - did you run the engine first without the DC chip? No matter you appear to have been back inside the model to add a different chip. I recently acquired a model of Raglan Hall and needed to remove the chip for use with Gaugemaster DS controllers. Raglan Hall ran really smoothly but it had a very pronounced tight spot when stopping and starting. Pretty obvious really, the hole for the water pump spindle in the body needed opening up so that the spindle was a slack fit. It might just be that you have put the body on sightly differently and that the spindle on your model is now binding. Regards Ray I was struck by this somewhat old post. I have just bought a second hand Conyngham Hall (from a well-known retailer). It looks absolutely pristine. I have chipped it for DCC and it seems to run just fine: running is smooth and well-controlled and slow speed is no problem. Then I put the body back on and the cab end bucks up and down once for every wheel revolution. Up when the right hand side slide bar (looking forward) is at its furthest toward the rear of the engine. I have oiled the motion and tried to make sure the slide isn't sticking as in this picture. And started "running in": about 20 minutes so far. It is a little better but still less than wonderful. I remember my father reporting after a footplate ride from Reading to Paddington that a Hall was less than smooth, but this might throw the crew off the footplate! Does anyone have any ideas? I would rather not try to return the item now! Link to post Share on other sites More sharing options...
Silver Sidelines Posted June 12, 2015 Share Posted June 12, 2015 Hello Froxfield ..Does anyone have any ideas?.. I had forgotten about this post. I have just purchased the latest Modified Hall and nearly wrecked the motion because the vacuum pump spindle was too short and jumped out of its slot and jammed - very nasty. Back to your problem - have you taken the body back off to see if the chassis still runs smoothly? If the answer is yes then something must be rubbing. I don't run any engines with chips in them but have you got all the wiring tidy from the plug and socket to the chip. Jumping once per revolution sounds like the coupling rods hitting something like the underside of the footplate or some stray wiring? If the answer is no - sounds like a cracked gear or even perhaps wheels badly quartered / slipping on their axle? Good luck Regards Ray Link to post Share on other sites More sharing options...
Froxfield2012 Posted June 12, 2015 Share Posted June 12, 2015 Thanks Ray. It runs fine without the body. Looks like a long slow process of elimination with the motion. I did wonder if that slide rod was a little too long and hitting the end of the plastic slide. But I am not sure if that would do it?! Richard Link to post Share on other sites More sharing options...
Silver Sidelines Posted June 12, 2015 Share Posted June 12, 2015 Hello again Richard ... I did wonder if that slide rod was a little too long and hitting the end of the plastic slide. But I am not sure if that would do it?!.. You might have found the answer. By slide rod - I am guessing the spindle for the vacuum pump attached to the footplate. Yes on Swithland Hall the spindle was too short so I repositioned the pump by about 1mm along the footplate. Yes in a past life I had a Bachmann Manor or was it an old split chassis Hall where the spindle was too long and certainly produced the symptoms you describe. I shortened the spindle using a mini cutting disc on a Dremel type drill. I have just measured the spindle on Guild Hall - it seems to be 12mm from the point where it is attached to the top of the crosshead. Good luck Ray Link to post Share on other sites More sharing options...
Froxfield2012 Posted June 13, 2015 Share Posted June 13, 2015 Hello again Richard You might have found the answer. By slide rod - I am guessing the spindle for the vacuum pump attached to the footplate. Yes on Swithland Hall the spindle was too short so I repositioned the pump by about 1mm along the footplate. Yes in a past life I had a Bachmann Manor or was it an old split chassis Hall where the spindle was too long and certainly produced the symptoms you describe. I shortened the spindle using a mini cutting disc on a Dremel type drill. I have just measured the spindle on Guild Hall - it seems to be 12mm from the point where it is attached to the top of the crosshead. Good luck Ray Hello again Richard You might have found the answer. By slide rod - I am guessing the spindle for the vacuum pump attached to the footplate. Yes on Swithland Hall the spindle was too short so I repositioned the pump by about 1mm along the footplate. Yes in a past life I had a Bachmann Manor or was it an old split chassis Hall where the spindle was too long and certainly produced the symptoms you describe. I shortened the spindle using a mini cutting disc on a Dremel type drill. I have just measured the spindle on Guild Hall - it seems to be 12mm from the point where it is attached to the top of the crosshead. Good luck Ray Thanks again Ray When the rain stops it's back out to the shed to see what I can do! Richard Link to post Share on other sites More sharing options...
Froxfield2012 Posted June 13, 2015 Share Posted June 13, 2015 Just a final thank you, Ray. A bit of fettling of the vacuum pump spindle and a thorough oiling of gear train and motion and things are much improved. And after an hour or so of running the actual mechanism is as smooth as any I have. There is still a slight wobble at some speeds (I have to suspect that the wheels/quartering may be very slightly out of kilter) but the result is satisfactory: at least to me. So thanks for the encouragement and advice! Richard Link to post Share on other sites More sharing options...
liathach Posted April 5, 2020 Share Posted April 5, 2020 Hello Bob, I converted to DCC two years ago. Being a fan of the GWR, I had four Bachmann Halls all DCC ready models. Same as you: they were silky smooth on DC. Put on to DCC, they have been the most challenging locos to get running smoothly, especially starting and then accelerating at low speeds. The staccato progression would be amplified with a load, as the wagons would snatch jumpily. I tried decoders and every conceivable CV variation I could think of: DCC Concepts, ESU, Lenz and my preferred ZImo decoders. I did find with Zimo, you could set CV9 for low frequency motor control, but this meant the motor made a very noticeable, unrealistic racket. Lenz I liked apart from the jump to speed speed one which I didn't find a fix for. I am convinced the specific issues with the Halls boil down to the combination of basic small three pole Buhler motor with the gear train output. On direct current, the motor rotation is smoothed out. I've seen elsewhere that a few people have managed to fit the current Hornby Hall chassis in to Bachmann Hall bodies as a work-around. I've tried to look to see if the current set of Bachmann Modified Halls share the same motor and gearing combination. Not seen a definite answer yet. Regards, John. Link to post Share on other sites More sharing options...
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