Good day all just got hold of an Atlas Loco ( GP35) with QSI decoder and the slow speed running leaves a little bit to be desired anyone had any experience with altering CVs to get it running better at slow speed Thanks Mervyn....
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I haven't run any AtlasO diesels with factory installed QSI DCC but do run AtlasO A-B-A FM Erie-Builts with aftermarket QSI Titan decoders. To improve low speed performance I followed the advice of Dan Dowling (posted on the defunct AtlasO Forum) and wired the dual motors in series as opposed to parallel.. The low speed performance was so good I didn't consider tuning the motor control CV's. Low current draw enabled use of a single "HO" QSI 1.8A Titan decoder in each dual motored unit.
It is my understanding that the firmware can be upgraded to V3 which is superior. Yes, V1 and 2 motor control sucks big time.
DCC NMRA standards have 2 methods of speed control on all decoders that are supposed to be DC C.
First you can control the starting voltage, accel, decel, midpoint and max speed with CVs 2-5. 2 is the accel rate and 3 is decel rate. I am not sure, but 4, 5, and 6 are start midpoint and max in some order. Settings these will give basic motor control and is all I ever use. By setting the midpoint and max, you set two slopes for the speed control by the throttle.
The second way is to set a speed table using about 20 or more CVs around 69. This gives you the ability to apply very fine motor control with whatever speed curves you prefer. I find it over kill.
In either case, the instruction sheet for the decoder should list the CVs and what they do. For the ones I mentioned, they are standard across all decoders and any instruction sheet should tell you what they are.
The best way to approach this if you have the equipment is to use Decoderpro by JMRI to do the programming using you computer. However, that requires buying a device to interface to teh system from your computer. The Decoderpro is free.
On the other hand, I have programmed all my locos up to the most recent using the master throttle that came with my Digitrax System. It might take a smidge more time, but is not that bad once you get started.
if the QSI decoder is a magnum Q1a version, the firmware is not upgradable to Q3. the revolution is not upgradable to Q3.
yes Atlas did have some later models with Titan Magnum decoders, but it all depends on the version. Titan does not automatically denote a Q3 ET decoder. they were introduced during the Titan run and will be noted as such. reading the firmware series will tell you (ex: 4000 series is Q1a, I believe Q3 is 7000 series).
decoders in both Atlas and Sunset engines are not the same exact design as ones purchased from QSI. there are specific files on the QSI Solutions site for those decoders.
Thanks for all the help ,have decided to bin the Atlas/QSI system and fit an ESU sound decoder hopefully this will also give me better motor control at slow speed ,bit disappointed after having bought the loco it isn't fit for purpose and you have to re manufacture it to get it running as it should do in the first place !!...
mervyn posted:Thanks for all the help ,have decided to bin the Atlas/QSI system and fit an ESU sound decoder hopefully this will also give me better motor control at slow speed ,bit disappointed after having bought the loco it isn't fit for purpose and you have to re manufacture it to get it running as it should do in the first place !!...
Hi Mervyn - Which is why I didn't buy any of the same locos that I suspect you were watching too on ebay.co.uk - our side of The Pond!!
It's just a pity that plain, straightforward (& cheaper!!) 12v DC 2-rail Atlas locos are getting as rare as hen's teeth now, it seems, to which we could add our decoder of choice.
From "F-UnitMad" of 'Over There'.....
Ha ha.... these RM web people get everywhere!!!! I was after the SW as I know they are great runners but then I thought oh well in for a penny in for a pound!! hopefully I can make a silk purse out of it ! Still looking for that elusive Alco tho!!
Hi Mervyn,
I understand your situation with the OEM decoder performance; however, on the bright side, I think you will really, really like the ESU replacement. These decoders very nice. If you have not already purchased your replacement decoder, I would highly recommend the ESU Loksound XL 4.0. Rip out all the existing circuit boards and mount this XL 4.0 decoder vertically in between the motors above the fuel tank (you’ll have to fab up an ‘L’ shaped bracket to mount the decoder vertically). You can try hooking up the motors either way, series or parallel to see which you like better. This XL 4.0 decoder generally runs just north of $200 US but it has screw terminals for connecting all the wires (easy-peasy), and is equipped with built-in keep alive capacitors sized for large scale locomotives – no more flickering headlights, hiccups in sound, or cleaning track for this locomotive. You will need to program the keep alive duration period with your ESU programmer or set the CV with the master throttle as they have the keep alive period rather short as it comes from the factory. As for the sound, it is awesome. The new FT Full Throttle feature allows you decouple the throttle setting from the sound by hitting the F9 key. This allows you to back off the sound while maintaining speed (run 8 sound all the time while running at speed for extended times can wear on your nerves a bit and really not that prototypical anyway) so being able to notch back the throttle once the train gets up to speed is really nice. Or vice versa, when climbing a steep grade or starting a long heavy train, you can keep the speed slow and load up the sound. I have a brass GP35 in the works that is getting an ESU Loksound Select L (can’t fit an XL 4.0 but I will add an ESU Power Pack Maxi to the install once they are eventually available here in the US) and this weekend I hope be shouting the immortal words of Dr. Frankenstein, “It’s alive…, It’s alive…” 
Scott K.
Austin, TX
Thanks Scott as soon as pay day arrives my order will be in for an ESU Replacement !!!
I've done an Atlas SDP 35. The China drives are poor slow runners, but I wired them in series and used an ESU Loksound L series decoder. Much better. It's still a bit lumpy on notches 1 and 2, but my mates say I'm being too picky. 
My Weaver GP 30-2 has been rebuilt with the P&D drive sets and the adjustable chain tower. On notch 1 you can hardly see it moving - and it's very smooth. I was so pleased with it, that I super detailed it.
No more China drives for me. 
Loksound XL or L, that is the question ha ha!!
The L is much cheaper than the XL, which to be honest I think is over-specced for O scale locos. The L will sit flat inside a Geep hood. My series-wired China-drives draw well under 1/2 an Amp current at medium speeds, less when switching, & I've even used an NCE DA-SR HO decoder (non sound) to run one Atlas loco, & a 1Amp Tsunami in my Atlas SW1200 (single motor of course).
I didn't used to think much of chain drive when my Weaver Geep was 12v DC, but I fitted a 3Amp "boosted" Tsunami from Norm at Protocraft to it, &, admittedly with a lot of CV tweaking, it now crawls really well indeed, with the bonus of the simple equalising mechanism of the trucks, so all wheels remain firmly on the rails of the rickety, rock'n'roll track I like to lay.
The only problem I find is that Tsunamis are very "fussy" decoders, & even fitting a KA hasn't fully cured the occasional stalls - even on the cleanest track - with attending sound & lights drop out. Unfortunately I bought this one just before Loksound announced the L series. Another option was a TCS Wowsound, which I have in my Atlas GP35, but I wasn't entirely sure that decoder (1Amp/HO) would cope with the power-hungry Pittman motor. I have a 2nd Weaver Geep on the workbench currently, & that will get a Loksound L.
Re RMweb; should I change my name over there to "Sunday Shunter", or change it here to "F-UnitMad"...??!!!
I Just got back from a 4 day Soundtraxx dealer workshop at their factory in Durango CO and was blown away with the new Tsunami 2 family of dynamic load sensing decoders. This provides much improved auto ( or manual) notching for diesels and variable chuff on steam. Their 2 amp Tsunami 2 for EMD has a full suite of EMD prime movers and a selection of 40 different horns. They have also revamped their motor control software. At a MSRP of $124.95 the new 4th generation decoders are worth a look. A 4 amp Tsunami 2 decoder for more current heavy locomotives is set for fall delivery. I have several 2 and 4 amp decoders on order and will post video's once installed. First up will be a Key H10 2-8-0 (2 amp) to be followed by a Sunset T1 using the beefier 4 amp Tsunami 2.
Whatever decoder you choose to use I recommend wiring the motors in series for better Lo speed performance. With minimal effort you could run some comparison tests with the existing AtlasO decoder. If it doesn't yield the performance you're looking for go the decoder replacement route.
I use the ESU LokSound Select in HO & N and I find them to run extremely well and sound amazing. If I were doing O scale I'd stay in the select line since most of the American loco sound files are for the select. The just released this one
http://www.esu.eu/en/products/...lect-loksound-l-v40/
Which I've heard great things about. Those Loksound XLs have mostly European sound sets
XL is designed for G scale. I have an RS-3 with one in it. I then piggy backed two other HO function decoders on to it, for step lights, cabin lights, number board lights and a supplementary smoke unit fan which cuts in with the increases in throttle settings, etc.
L is plenty for O scale 2 rail.
I wholeheartedly agree that the XL 4.0 is a bit overkill for some or even many O scale locomotives; however, built-in keep alive equivalent to the Loksound Power Pack Maxi (currently trending around $62 US, but that is after European street price conversion so not sure where the final US price will land) and it has screw terminals which are very convenient for installation. I've done a select L (and will do another this weekend) and those solder pads are quite small so you need to have some pretty good soldering skills. Based on the cost comparison after you factor in the price of a Loksound Select L (~$125) + Power Pack Maxi (say + $55 but just guessing) + the convenience of screw terminals (+$10 for time savings and terminal block cost) = $190 vs. $203 for a Loksound XL 4.0 that will accept any ESU sound file you can throw at it regardless of sound file size. I would say the Loksound XL is still competitive at the end of the day to the Select L barring any space restrictions that prevent you from using the XL or you don't want keep alive capability.
Scott K.
Austin, TX
For those who missed it the first time . . .
https://www.youtube.com/watch?v=yDDA6nkM6fU
I know it's the wrong engine sound; but I like it. 
That is stunning ! Thanks for sharing if my Loco runs as sweet as that after conversion I will be well pleased!!!
Thanks, Mervyn.
Here's a link to the trials and tribulations of the journey.
https://ogrforum.com/t...10#47467209136517110
I had a lot of help from people on here.
Cheers
