Simon Moore Posted January 2, 2012 Share Posted January 2, 2012 Recently i have had a sweep of my stock & fitted decoders to most of the fleet that is for Austwick. The Trainsave & Gaugemaster decoders are faultless & work like a dream but the Bachmann decoders are a different story. I have about 5 Bachmann decoders fitted to a selection of steam locos. I've just fitted a crab & a 3f with a 8 & a 21 pin Bachmann decoder & both locos are running exceptionally erratic . The 21 pin decoder has just come out of a class 150 dmu & that ran fin but as soon as i fit it in the 3f it judders badly & will go very slow then as soon as you touch the speed control to slow it down it jerks but with speed. The crab has been doing the exact same thing can anyone tell me what i'm doing wrong to them?? Cheers Simon Link to post Share on other sites More sharing options...
Sam Moss Posted January 2, 2012 Share Posted January 2, 2012 I think its probably somethign to do with interference caps and back EMF. My cousin has just changed over to digital and for xmas he got a dcc fitted super D. It runs like a dog. On DC it runs lovely but on DCC runs awful. Have clipped off all caps and altered some CV's for start voltage etc. Next step is to alter back emf settings to see if that does it. Link to post Share on other sites More sharing options...
Simon Moore Posted January 2, 2012 Author Share Posted January 2, 2012 It's really strange this Sam i've just swapped the 21 pin chip back to the dmu & thats running perfectly fine on DCC. I'm sure how to change CV's i am more or less a DCC virgin. I've only fathomed out how to change numbers & use the DCC system i have. Do you have any tips for the 8 pin decoder to change the functions etc to give it a smooth ride?? Link to post Share on other sites More sharing options...
johnd Posted January 2, 2012 Share Posted January 2, 2012 (edited) Think I would try the CV settings for the motor first have a 21 pin in a 3f and it runs fine, try decreasing CV54 from the default 32 and increasing CV 55 from the default 24 thats all i did and as I say the 3f is fine Try the same on the 8 pin decoder but keep a record of the default and what you change it to. have a look at the CV table as supplied on the back of the info sheet. you cannot damage anything by altering CV's as I said keep a record of what you alter. Motors can be different and changing the above CV can cure what your experiencing Edited January 2, 2012 by johnd Link to post Share on other sites More sharing options...
Simon Moore Posted January 2, 2012 Author Share Posted January 2, 2012 John thank you for that bit of info there i have had a tinker with it & its not jerky although there is fine tuning to be done to get it bang on but it's getting there. Simon Link to post Share on other sites More sharing options...
johnd Posted January 2, 2012 Share Posted January 2, 2012 (edited) John thank you for that bit of info there i have had a tinker with it & its not jerky although there is fine tuning to be done to get it bang on but it's getting there. Simon If you havn't the decoder sheet here is were it is on the Bachmann website. http://www.Bachmann....ion_decoder.pdf Edited January 2, 2012 by johnd Link to post Share on other sites More sharing options...
Orange Alco Posted January 4, 2012 Share Posted January 4, 2012 Recently i have had a sweep of my stock & fitted decoders to most of the fleet that is for Austwick. The Trainsave & Gaugemaster decoders are faultless & work like a dream but the Bachmann decoders are a different story. I have about 5 Bachmann decoders fitted to a selection of steam locos. I've just fitted a crab & a 3f with a 8 & a 21 pin Bachmann decoder & both locos are running exceptionally erratic . The 21 pin decoder has just come out of a class 150 dmu & that ran fin but as soon as i fit it in the 3f it judders badly & will go very slow then as soon as you touch the speed control to slow it down it jerks but with speed. The crab has been doing the exact same thing can anyone tell me what i'm doing wrong to them?? Cheers Simon You need to set Back emf CVs 54 and 55 to be something appropriate to the motor you are controlling, the defaults are fine for larger motors but not smaller lighter ones which is why it would have been okay in the Class 150. The Bachmann DCC Onboard steamers usually come with with CV54 at 12 and CV55 at 60 so try that for the 3F. IIRC the decoder paperwork says thase have to be altered otherwise there may be poor slow speed running.. Link to post Share on other sites More sharing options...
mkwolf1877 Posted January 4, 2012 Share Posted January 4, 2012 I've just fitted a Bachman 21 pin chip to a Bachman 150 and it runs very erratically, mainy very jerky. Can anyone recommend what to change cv's too on this? Many Thanks Link to post Share on other sites More sharing options...
steam in 50s Posted January 5, 2012 Share Posted January 5, 2012 (edited) Could some one please explain how to change cvs i also have a Bachmann 4-6-0 and it runs erratic at slow speeds. ps it came with chip on board. Edited January 5, 2012 by steam in 50s Link to post Share on other sites More sharing options...
smokebox Posted January 5, 2012 Share Posted January 5, 2012 Which controller are you using? Link to post Share on other sites More sharing options...
Combe Martin Posted January 5, 2012 Share Posted January 5, 2012 The default settings for Back EMF in the Bachmann 21 pin decoder seem to be for diesel mechanisms (which may have larger motors and/or flywheels fitted) and they don't suit their modern steam locos at all. This most obviously shows up when trying to run a loco at it's absolute minimum speed, like walking pace or less. I've just put one in a 3F and set CV54 to 1 and CV55 to 60 (minimum and almost maximum values) and though it's much better, it still dosn't run as well as on DC. However, I havn't found a decoder yet that can run a modern Bachmann steam loco at walking pace as well as just on pure DC. The best ones have been ZTC, Lenz, and Digitrax (TCS was awful). The problem seems to be the 3 pole motor Bachmann use. It just dosn't seem to run as well on DCC as DC. Hornby locos are fine, but they have a much better 5 pole motor fitted. They even run well with the cheap Hornby decoder fitted. Ironically, the smoothest running Bachmann loco I have, is a split chassis Ivatt tank fitted with a Digitrax DN135D. But then these do have a different motor (though I don't suppose it's a 5 pole) and no capacitors are fitted. Link to post Share on other sites More sharing options...
34theletterbetweenB&D Posted January 5, 2012 Share Posted January 5, 2012 It is best to take off the three capacitors that Bachmann hang on their motor. Then either of a Lenz or Bachmann's 36-553/4 will make the small Bach 3 pole motors perform beautifully; the Bach decoders do need CV's 54 and 55 adjusted as you know. Leave the capacitors in, and you will often see what appears to be cogging or slight jerkiness at dead slow speed. Once in a while it doesn't happen, my example of the G2A is an example and still has the cpapacitors installed as a result, but I usually just take them off routinely before fitting the decoder. In my new 3F, the Lenz silver enables the little thing to plod along at a smooth scale half mile an hour with sixty wagons behind it. Good enough? (The 36-554 works equally well for smoothness at low speed, but doesn't have a great enough range in CV3 in particular to model the feeble acceleration performance of this machine for my taste...) Link to post Share on other sites More sharing options...
Simon Moore Posted January 5, 2012 Author Share Posted January 5, 2012 Could i have a bit more information about these resistors & what is involved in removing them is it simply cut them off & that is that or is there any additional wiring or soldering needed ?? I'm new to this playing field entirely so it is all new to me. I've learnt about the CV changes etc but not sure about resistors & i don't fancy doing something drastic to a brand new model. Also does this go for the ivatt 2mt, crab & fairburn etc. The other thing is if i cut those off will they still work well with gaugemaster decoders?? Simon Link to post Share on other sites More sharing options...
craigwelsh Posted January 5, 2012 Share Posted January 5, 2012 Could i have a bit more information about these resistors & what is involved in removing them is it simply cut them off & that is that or is there any additional wiring or soldering needed ??Also does this go for the ivatt 2mt, crab & fairburn etc. The other thing is if i cut those off will they still work well with gaugemaster decoders?? Simon You dont need to do anything with resistors if there are any on the model. They will be there to slow the motor down. What you remove are the capacitors that provide interference suppression on DC. The capacitors are usually on the end of the motor across the two connectors. You just snip the one leg and leave them there but disconnected. Removing them should make all decoders work better as the decoder will be getting a true back EMF then from just the motor. Link to post Share on other sites More sharing options...
steam in 50s Posted January 5, 2012 Share Posted January 5, 2012 (edited) I am useing the Hornby elite at the moment because not changing until later on in year smokebox. Also looking into what you have said craigwelsh. thanks Edited January 5, 2012 by steam in 50s Link to post Share on other sites More sharing options...
34theletterbetweenB&D Posted January 5, 2012 Share Posted January 5, 2012 To amplify further on the above. Capacitors are the litle orange-brown 'blobs', with two wires coming out the same side. They bridge the motor brushes rather than being connected in series with the motor leads. Leave any components in series in place. Link to post Share on other sites More sharing options...
Simon Moore Posted January 5, 2012 Author Share Posted January 5, 2012 Just to make double certain i am doing the right thing once i've cooked the tribe there teas i've take the lid off one of the locos & just point what i think they are with a photo & then post to make sure i am doing the right thing. I've been doing a been of fine tuning on Austwick this afternoon & getting the slip to work better & i have had a gander at the ivatt 2mt so i think i know what to snip. Simon Link to post Share on other sites More sharing options...
Simon Moore Posted January 5, 2012 Author Share Posted January 5, 2012 I've taken a few shots of the chassis the Fairburn has 3 of those blob capacitors do i snip all of them including the one on the PCB ???? I've included the photos below i've pointed at them with a screwdriver am i cutting all of these to give better back emf. Fairburn Crab Cheers Simon Link to post Share on other sites More sharing options...
Dr diesel Posted January 6, 2012 Share Posted January 6, 2012 (edited) Hi Simon Those are the chaps. Take out all three of them. They are put in by the makers due to legislation on such things as tv interference, but dcc decoders.have this requirement built in. Regards Jeff Edited January 6, 2012 by Dr diesel Link to post Share on other sites More sharing options...
mkwolf1877 Posted January 6, 2012 Share Posted January 6, 2012 Which controller are you using? Lenz LH100 Link to post Share on other sites More sharing options...
RMweb Premium brushman47544 Posted January 9, 2012 RMweb Premium Share Posted January 9, 2012 I do find it frustrating that you need to change CVs 54 and 55 for most Bachmann steam locos yet Bachmann's entry level E-Z Command system doesn't have that option available. Very shortsighted in my view and is why I tend to buy Bachmann locos decoder fitted where available. All of mine have run perfectly with the pre-set values of CVs 54 and 55 - no jerkiness whatsoever. Perhaps I've been lucky, but it is in my view incumbent on Bachmann to ensure that a DCC fitted model works with the pre-set CV settings. If not as a customer you can take it back to your retailer as not fit for purpose and get it "fixed" or replaced. As to capacitors, I leave them in place. I can't snip them even if I wanted to because I need to be able to run the locos on DC as well occasionally and once snipped you can't go back - at least not without soldering. Anyway, the model should work properly on DCC with them fitted or arguably it's not fit for purpose. Link to post Share on other sites More sharing options...
JZ Posted January 11, 2012 Share Posted January 11, 2012 I had this problem with an Ivatt 2MT. I emailed Bacnmann and recieved this reply The Ivatt needs to have adjusted settings although the defaults are fine for the size of motor in the Class 25. For the small motor in the Ivatt, set CV 54 to around 10 to 12 and CV 55 to about 60, adjusting the value until you find your model runs its best. Link to post Share on other sites More sharing options...
RMweb Premium brushman47544 Posted January 12, 2012 RMweb Premium Share Posted January 12, 2012 I had this problem with an Ivatt 2MT. I emailed Bacnmann and recieved this reply CV54=12 and CV55=60 is what Bachmann recommends (at least as a starting point) for all the smaller models, e.g. Panniers, Small Prairies, BR Std 3 and Std 4 tanks. The DCC Fitted versions I have are pre-set to those values. Link to post Share on other sites More sharing options...
Chrisr40 Posted January 18, 2012 Share Posted January 18, 2012 Hello all - sorry to barrel in but thought i would add my experiences too - in case I can gain some knowledge from them being shared. I had a Bachmann 4mt loco that was dcc fitted and I had it converted to dcc sound by Keytes - the upshot being that I got back a sound fitted loco and a spare 8 pin Bachmann chip. Now I was lucky enough to obtain a 2mt recently and it being dcc ready I thought I had a good use for the spare chip - but it runs much as described in earlier posts. I even tried it in a completely random loco - a Hornby class 59 and it gave the same bad jerky performance. I hasten to add both run super smooth on dc. I dont have the luxury of a controller that can change cv's - only the ez command so Im wondering now if this chip is any good or should I just go for the basic Hornby one that seems to be a good jack of all trades ? Chris Link to post Share on other sites More sharing options...
RMweb Gold Nickey Line Posted February 17, 2012 RMweb Gold Share Posted February 17, 2012 (edited) CV54=12 and CV55=60 is what Bachmann recommends (at least as a starting point) for all the smaller models, e.g. Panniers, Small Prairies, BR Std 3 and Std 4 tanks. The DCC Fitted versions I have are pre-set to those values. I had a similar issue with a recently purchased Bachmann 3F and found that the loco performs best with back EMF turned off altogether... will go at a smooth crawl no probs, and quiet too. With back EMF on (any settings) it becomes noisy and jerky. Just my experience with one particular loco but may be of use to someone. Sometime later...! After further experimentation I've found that the jerkyness can be cured by turning off the DC bit in CV29... Edited April 4, 2012 by whinge-n-moan Link to post Share on other sites More sharing options...
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