M Graff Posted June 3, 2011 Share Posted June 3, 2011 Hi all! I have an US outline layout, and I have "some" Bachmann locomotives since before, but only steam engines and in the Spectrum series with sounds. I found, however, a "70 ton diesel" cheap as heck on ebay, so I thought, that I can see how they are ..... And it's a great starting point for my next build B) It was in their DCC onboard series (pre-installed decoder). I got it yesterday, and put it on a track oval to test and run it in. But what a disappointment! It sounded like a grinder, no low speed, erratic running, low light and virtually no CV's to change in order to improve matters (no Vmax or Vmid, no BEMF or PWM setting ....). The momentum made matters worse..... The decoder has high and low beams! Which the locomotive did not need at all! I tried to run it for an hour, but it made no difference (some Bachmann locos need running in). I quite resolute opened the locomotive and looked under the hood. There they had a combined decoder and light board! Shoot ... but it did not matter much as the original lights were so bad ...... In addition, it was the type with plastic clips that locked the wires to the PCB. So the least you may do Ãs to solder them (if you can stand for the poor decoder ....). I myself have not experienced such a bad decoder for 10-15 years! I tore out the original decoder and took the opportunity to dismantle the entire engine in molecules (always good to see if there is more to address .....) On the engine, they had capacitors they were removed and then I soldered in a Lenz Silver decoder wich I mounted above the motor. All wire colors was right in the original, black on the left side of current pick up etc. I also made two small circuit boards with 1-Kohm resistors, and warm white frosted 3mm LEDs. They were in the same location as the original so that the lights would be right. The test run commenced, what a difference! It is not even comparable to before. The fact that a decoder can "destroy" a loco to that extent! The light was so much better than before (why have yellow LEDs ???). Why is Bachmann not investing in better decoders? They have otherwise very good Sound-decoders in their "Onboard Sound"- series (Tsunami). Here´s a film that shows the difference: http://www.youtube.com/watch?v=TCJE7rqGDmE&feature=player_embedded So the conclusion is that the loco is good if you change the decoder ..... I just realised that the decoder cost nearly twice as much as the engine However, I have run the engine a bit more now and it gets a little bit smoother in the mechanism, and now I can hear it! Link to post Share on other sites More sharing options...
shortliner Posted June 3, 2011 Share Posted June 3, 2011 Michael - that is very interesting - the old twin-motors (DC) ones crawl straight out of the box on PWM controllers, I have several - why the DCC version, single motor doesn't behave , I don't know. There have been coments elsewhere that the Bachmann DCC chip has some, shall we say - "limitations" Link to post Share on other sites More sharing options...
warbonnetuk Posted June 3, 2011 Share Posted June 3, 2011 I use 70 Tonners pretty much exclusivley on 'Galatia KS' (well the two I have anyway) and I've found then to be brilliant value for the price. I'll 'fess up now and say that I have stripped out the Bachy decoders and fitted Loksound v3.5 but I did run both straight out of the box in order to test and they were both pretty good runners. In terms of chip installation it pretty straightforward in terms of hard wiring the chip in but once you have removed the 'as supplied' board there is loads of room. The main issue I've had is where the guy in China assembling model trains feels the need to use a whole tube of teflon lubricant each individual gear. This manifested itself at the layouts last outing with both GE's running like 3 legged dogs despite copious wheel tread and rail cleaning. However after removing both wheel sets and removing the excess lubrication on the truck pick-up they ran perfectly. In the process of installing a Cummins Micro Tsunami in a GE 45 Tonner but thats a different story......... Dan Spalding Link to post Share on other sites More sharing options...
Prof Klyzlr Posted June 3, 2011 Share Posted June 3, 2011 Hi all! I have an US outline layout, and I have "some" Bachmann locomotives since before, but only steam engines and in the Spectrum series with sounds. I found, however, a "70 ton diesel" cheap as heck on ebay, so I thought, that I can see how they are ..... And it's a great starting point for my next build B) It was in their DCC onboard series (pre-installed decoder). I got it yesterday, and put it on a track oval to test and run it in. But what a disappointment! It sounded like a grinder, no low speed, erratic running, low light and virtually no CV's to change in order to improve matters (no Vmax or Vmid, no BEMF or PWM setting ....). The momentum made matters worse..... The decoder has high and low beams! Which the locomotive did not need at all! I tried to run it for an hour, but it made no difference (some Bachmann locos need running in). ... So the conclusion is that the loco is good if you change the decoder ..... I just realised that the decoder cost nearly twice as much as the engine However, I have run the engine a bit more now and it gets a little bit smoother in the mechanism, and now I can hear it! Dear Michael, Very interesting (and greatly appreciated!) observation, but I have to say that as someone who's only ever run my new "dcc-equipped" B'mann locos on analog DC, (via my AUD$20 Homebruise single-transistor throttle), the "oem" decoder behaviour is no significant impediment to achieving "drop it on the track, and achieve 1 sleeper/min crawly performance, right out of the box". I applaud your courage to "open it up and have a look", it wouldn't be the first time that a poor assembly QA on a B'mann loco has hamstrung it's out-of-box performance. I also know that the "Phase 3" (centre-motor) 44-tonner mechs have the worms rigidly mounted to the frame, with the truck and worm-gear forced to "swivel underneath" the worm. (unsure if the 70 tonner has this same system, but it can cause additional binding and noise under tight-turn conditions). Happy Modelling, Aim to Improve, Prof Klyzlr Link to post Share on other sites More sharing options...
shortliner Posted June 3, 2011 Share Posted June 3, 2011 Those do look very smart in that colour scheme - nice one! Link to post Share on other sites More sharing options...
CraigZ Posted June 4, 2011 Share Posted June 4, 2011 The Bachmann decoders look like they're about 15 year old technology...they can be pretty awful. Having said that my 45 tonner runs very nicely with its Bachmann decoder. Curious indeed... Link to post Share on other sites More sharing options...
Gene Posted June 4, 2011 Share Posted June 4, 2011 I think the Bacchy US outline locos run the gamut from very good to awful out of the box...I have 2 70 tonners that ran beautifully out of the box but are noisy, which I'm not fussed about since the noise subs for the sound chip. I have 3 Bacchy saddle-tank 0-6-0s, 2 are factory chipped and one is a 6 year old DC one that I chipped last year...the 2 factory chipped ones run well...but nowhere near as well as the one I chipped. My 2 DCC 45-tonners ran perfectly and quietly right out of the box. It really seems to be a crap-shoot. Warbonnetuk please let us know how the Cummins micro Tsunami install goes....I just found out about that decoder yesterday and was thinking about trying one in one of my 70-tonners.... Cheers Gene Link to post Share on other sites More sharing options...
298 Posted June 6, 2011 Share Posted June 6, 2011 You get what you pay for with decoders, and the Bachmann one is a good example of why modellers prefer to fir their own choice than have to put up with a "one size fits all" that only suits those who use DC or want something to play with unaltered out of the box. The current 44t & 70t chassis are dimensionally identical, the only major difference being the fuel tanks and the motor orientation, the 44 tonner has it's motor installed with the flats mounted vertically, whilst the 70 tonner has them horizontal (which seems odd considering there's more room in the centre cab's body. My models of 298 use a current-type 44 tonner chassis, as the dimensions are correct for a GE Steeplecab. More expensive solutions would give a better chassis but I'm happy enough with mine and the mechanical work for the conversion is really simple. Negative issues are the pickups (sorted by soldering a length of phosphor bronze strip to the pickup plates), and some motors can be noisy. Having the worm over the truck isn't really an issue and allows the chassis to negotiate some tight radius curves, but one issue with this is the lateral slack in the truck mounting means the truck will move before the body. Oh, and the split axles are prone to splitting. So on the whole they're quite good, but the difference between them and proper switchers such as an Atlas S-4 are apparent. Link to post Share on other sites More sharing options...
Prof Klyzlr Posted June 6, 2011 Share Posted June 6, 2011 You get what you pay for with decoders, and the Bachmann one is a good example of why modellers prefer to fit their own choice than have to put up with a "one size fits all" that only suits those who use DC or want something to play with unaltered out of the box. Dear RMwebbers, Thanks for holding the Door open for me Dave, but I'm resisting walking thru it... Happy Modelling, Aim to Improve, Prof Klyzlr Link to post Share on other sites More sharing options...
Prof Klyzlr Posted June 6, 2011 Share Posted June 6, 2011 The current 44t & 70t chassis are dimensionally identical, the only major difference being the fuel tanks and the motor orientation, the 44 tonner has it's motor installed with the flats mounted vertically, whilst the 70 tonner has them horizontal (which seems odd considering there's more room in the centre cab's body. Dear Dave, Interesting, I'd not noticed that, although I could have sworn the 70s had a longer truck<>truck spacing than the 44s. Must dig mine out of storage and compare when I get home from work... Thanks for the head's up! Happy Modelling, Aim to Improve, Prof Klyzlr Link to post Share on other sites More sharing options...
Gene Posted June 7, 2011 Share Posted June 7, 2011 Prof...I just checked and from what I saw you are correct ...the truck<>truck spacing does appear to be wider on the 70 than on the 44 Dear Dave, Interesting, I'd not noticed that, although I could have sworn the 70s had a longer truck<>truck spacing than the 44s. Must dig mine out of storage and compare when I get home from work... Thanks for the head's up! Happy Modelling, Aim to Improve, Prof Klyzlr Link to post Share on other sites More sharing options...
298 Posted June 7, 2011 Share Posted June 7, 2011 I've just checked two of the earlier chassis and you're right, the 70 tonner is 1.2mm further apart. Why didn't I notice that before....? Link to post Share on other sites More sharing options...
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