Quote from: StanAmes on April 02, 2015, 03:19:12 PM

JV

The Tsunami TSU-1000 is not an appropriate decoder for the K27 for many reasons

1) insufficient current for the K27
2) DCC track voltage in Large Scale is higher then the Tsunami TSU-1000 support
3) The K27 needs both a decoder + and decoder - connection to operate properly.  Most Large Scale decoders support both.  Many decoders designed for smaller scales do not.

Soundtraxx announced a decoder for the Large Scale socket found in the Bachmann Spectrum locomotives but to date has not released the product.

BTW another good alternative is a non sound decoder and a sound only card. The SJR&P uses Lenz Gold Maxi decoders with Phoenix sound`

Thanks for your reply, Stan.  I mentioned the Tsunami not as a candidate for the K27, but as an example of exhaust chuff triggering that is not referenced to ground; I was reacting to your comment "The K27 has a positive trigger and the decoders desire a ground trigger."  I don't know how other encoders are triggered, but I can say for sure that this one doesn't 'desire a ground trigger.' 

Regarding the track voltage, the Tsunami does indeed comport with the NMRA track voltage standard, i.e., maximum operating voltage of +/- 22V, absolute maximum voltage of 27V.  This is in NMRA s-9.1_electrical_standards_2006, and the Soundtraxx Tsunami documentation.  I would point out a flaw, or imprecision in the NMRA standard in that it cites the absolute maximum voltage by saying that the decoder "shall be designed to withstand a DC voltage of at least 27 volts," without mentioning an upper bound; it should state, in my opinion, the maximum voltage one will see on the track, and that would be stated as a maximum, not "at least."  But I digress.  The Tsunami complies.

On the third point, I don't understand that: what is "decoder +" and "decoder -"?  Is this the same as the pins 6 and 7, "decoder positive" and "decoder ground" in the document you sent me?  (Topic 0707092 Large Scale Plug-socket.pdf) 

Thanks,

jv

Quote from: StanAmes on April 02, 2015, 09:07:09 AM

Quote from: joeaug1025 on April 01, 2015, 10:48:00 AM
What manufacturer(s) make a DCC decoder with sound for the Bachmann "F" scale (1:20.3) K27 that plugs directly into the PC board connector

The problem is the chuff.  The K27 has a positive trigger and the decoders desire a ground trigger.  It is easy to insert a transistor to invert the chuff. See the documentation that Bachmann has on its site for instructions.

Hi Stan.  I'm brand new to DCC, and the only decoder I have is the Soundtraxx Tsunami TSU-1000, and my reading of the docs was that it wanted a trigger from the rail.  That's because the installation manual explains how to wire a trigger wire that is insulated from the frame and connected to the chuff input, , and contacts a "cam" disc that is adhered to a driver wheel, the conductive sectors of which are electrically connected to the driver, and thence the rail.

Perhaps even more to the point, there is no ground reference exposed from the Tsunami decoder!  The "function common" appears to be a Vcc reference, the function outputs apparently open-collector outputs.  Other than speaker outputs there's rail in and motor out; no ground reference.  To have a ground reference you'd have to make a guess as to how Soundtraxx established this inside the decoder, and then synthesize this with a circuit outside, perhaps a FWB rectifier and assume the more negative of the rectified output of is "ground."  

What I am saying in a roundabout way is that in DCC, because the rail voltage is alternating, there is no "ground."

Do I have this wrong?

Thanks,

jv


UPDATE: I just today wrote to Soundtraxx support, and they responded, and have confirmed what I surmised about the chuff input: it's "looking for rail power."

Sorry, I was just in a particularly nerdy mood.

Bill, with all due respect, while you say "I said it should be OK to put a ''drop" under the cover," you said no such thing.  You said "should be ok unless you are running outside in dusty conditions" in response to "s it advisable to remove the cover plate and put a drop of light oil on the motor shaft that exits the housing of the motor?"

 

http://www.bachmanntrains.com/home-usa/board/index.php/topic,23261.0.html

Bill, kinda surprised by that response.  Also, the post Bob, are you saying "is it O.K. to lubricate the motor bearings?"  I would say, yes, that it's not only "O.K.," but that it's necessary for long life and proper operation.  The thing that Bill may be getting at is that one source of trouble, in addition to too little lubrication, is too much oil.  Oil all over will pick up dirt, and that can lead to problems. 

My view is that the slightest amount of quality machine oil, i.e., not detergent motor oil, ever, is best.  If you could get 1/2 a drop of oil onto the shaft so that it runs into the bearing and leaves a film of oil on the mating surfaces of the shaft and bearing, that's perfect!  Wipe off the extra right away. 

Almost done!  I wired lights, speaker in the tender, made nice, round section loco to tender cables, everything; received my new (and first) DCC system, the Digitrax Superchief Xtra 8 Amp, and - nothing!  Turns out I wired the lead truck pickups backwards, and presented a dead short to the rails!  Yikes! At least I know the short circuit detection works.

It was upside down, and I got my right/left, red/black backwards.  I'm having trouble with that lately.  Oh well, tomorrow's another day. 

p.s. found speakers @ 2 for $9.50, shipped.  Look identical to Bachmann stock. 

Quote from: Hunt on March 29, 2015, 09:27:16 PM
Also review CV 112 documentation. You must program CV 112 to enable Cam Synchronized Exhaust.  The default setting is Auto Exhaust Chuff Enable.

Yes, saw that, thanks.

So, I've hit a glitch here.  The exhaust cam connection, i.e., "chuff trigger," is not described electrically in the Tsunami manual; at least not explicitly.  They way I take it, the chuff input makes and breaks contact with the rail - either one - to synchronize the exhaust sounds.  Is this correct?

The reason I think this is so is that the manual explains installing the exhaust cam on a wheel, and stresses that this disc must be electrically connected to the driver wheel to which it's mounted, and the wiper that contacts it is mounted on an insulated board, and connected to the exhaust cam input of the decoder.

Just checking - don't want to burn up anything.  If you know, please let me know!

Thanks,

jv

Quote from: Ken Clark on March 29, 2015, 11:27:13 AM


      JV

   Coronado Scale Models offered plans by Edward H Cass for the ET&WNC engines # 10-14 in 1/4" scale, not sure if still available or current price.


   Ken Clark
     GWN

Thanks, did a search, looks like they are out of business.

Where can I find the drawings for the prototype of the Baldwin 4-6-0 locomotive modeled by Bachmann?  I'm talking about free, online, ideally, but I might pay for a really nice, large size hard copy.  I've started searching, but so far I'm coning up dry.

Thanks,

jv

p.s. why does the bulletin board think that 'drawings' is misspelt in the title but not in the body of the message?

Update.

Started rewiring the chassis for DCC.  There are a pair of molded-in binding posts just forward of the motor, facing down, that the bulk of the positive and negative wires are fastened to with screws through ring terminals.  I removed the screws and pulled all the wires out.  Found a couple of things I didn't like.  First, all the wiring has been given a shot of black paint.  Not sure why, maybe so one won't see the red wires through the holes in the sides of the frames?  I don't care for the pin and socket connection of the rail power wires to the brass wipers, so I'm eliminating those in favor of stacking a ring terminal on the existing one to the leading truck pickups.

I found both the wires to the leading truck pickup sheared clean off at the truck swivel post.  It seems someone myst have twisted the truck all the way around (not me!).  This was a pain to re-do.  I don't care for the design of the wire routing through the post.  I also can't see how this arrangement makes good contact from the rails to the pickup wires, it doesn't seem there's positive contact from the wipers to the axles, and the axles don't even look like they're clean enough to make decent electrical contact.  The truck seems too light, too.  This is a generation 5 chassis, perhaps these issues have been addressed in gen. 6?  The wires had been tacked into the frame floor with hot glue, and thy had pulled out of this.  I tacked the re-done wiring with drops of extra-thick cyanoacrylate adhesive.  It required some accelerant to "go off." 

Still haven't settled on what I want to standardize on for connectors on my railroad.  I ordered some 28 ga. wire, tinned, stranded, ten colors.  I had contacted Soundtraxx support about purchasing their very nice, flexible wire, and they were kind enough to accommodate me, but the prices was just too high.  I don't think they are gouging, at all, it's just good, expensive wire.  I went the Chinese route via eBay; it's purported to be tinned and stranded 7x19, we'll see.   It was about 1/15th the price of the good Soundtraxx stuff.  I did purchase a few pairs of the connectors that are used for the loco to tender wires.  The receptacle is intended for a wire, and pin header for PCB; but, I'm sure I can use the header for wire attachment with decent soldering and good heat-shrink, which should provide some mechanical reinforcement as well as insulation.  I'll use the rear PCB as a bulkhead for the tender speaker and backup light connections, maybe use the switch just to turn the speaker on and off.  I'm going to find some very soft, round section, two conductor stuff for the loco to tender so it looks like a couple of hoses and doesn't cause derailments as the to-stiff stock cables do. 

Lacking a connector decision and connectors I'll mate the decoder to chassis wires with solder and heat shrink, except I'll use one for the two pin header and receptacle pairs to connectorize the headlight, easing maintenance, allowing separation of the shell and chassis.  (I will forgo a smoke unit, and any switches ender the smoke box door for now).  I have some perfect, tiny heat shrink tubing.  I think it might even have an adhesive inside.  The only connection that makes me think a bit is the blue, "Function Common" wire, which has to be connected to both head and tail lights, and two more functions, if used.  It would be nice to have a common bus, but it's unnecessary, I can just leave a pig tail hanging out of the splice in case I want to add F5 and F6 functions at some point. 

This brings up a point about smoke units.  I don't know how much power they require, but I'm guessing it's more than the maximum of 100mA that the rating of the function outputs.  Further, there's no good reason to drag all of this power through the decoder.  If I add one I'll probably just run it on the DCC raw, through a tiny relay that's controlled by a function output, or a switch.

I toyed with the idea of using the NMRA/LS polarity switch as a switch to go from DCC to DC, but I just don't want to think that much about it at this point.  I'm guessing I'd need more poles if I'd want lights with DC, etc.

I noticed some slop in the motor, i.e., it swivels up and down a bit when pressure is applied to the drivers forward and reverse.  Is this normal?

I'll probably strap the decoder to the top of the weight with a nylon tie-wrap, and leave the wire-lenght on the decode so the weight can be placed aside for maintenance without having to cut the tie wrap. 

So, still not done, but the end is in sight.  It's more work and time than I imagined.

Thanks Hunt, gotcha.  That was my next move.

Quote from: Joe Zullo on March 25, 2015, 09:20:36 AM
5mm LED's are the correct size.  

Not quite so.  I received my 5mm LEDs today and the don't fit.  The reflector into which they insert, form the rear even has a tab to located the bent leads, but the hole is only 3.85mm.  Inside the reflector, the barrel into which the LED will slide is just a bit over 5mm, so I guess if I open up the hole they will work.  But I can't remember if I have a metric drill bit set or reamers - will have to check.  The closest fractional equivalents are 13/64, which is .006" over 5mm, and 3/16", which is .010" under.  Will have to think about this....

Update: found a 5mm bit, but it turns out the 'barrel' that the LED slides into is not 5mm, it's a bit smaller, so trying to drill it out for 5mm would likely wreck the reflector.  So, fortunately the LED vendor on eBay has 3mm LEDs and does returns with free shipping!  He also processes orders and ships very quickly, so all good.

Update 2!: I have to apologize to Joe, 5mm is the correct size, but not the kind I had with the rim around the base.  I ended up holding these in a collet on the lathe and cutting off the rim.  I turned them so they are a nice, tight press fit in the reflector.  Now I have a whole lot of 3mm LEDs, and slightly fewer 5mm. 

I made some more progress on this.

I swapped the drivers from the dummy to the new chassis, so I'll have the proper wheel trim.  Likewise the leading truck wheels, which just pull apart easily.

I the new chassis has the nice, Walschaerts valve gear.   I don't know if this is "correct," for Baldwin 4-6-0's, or this era (1905 or so?), but it looks great.

In my specification for this is to add two trigger strips for the chuff trigger, so I'll have the correct four chuffs per revolution.  When I too the lead driver apart I found, much to my surprise and delight, that the drum, or spacer, or whatever the part is called to which the trigger strips are attached is designed for four strips!  I wonder why Bachmann doesn't attach the additional two strips, but if I can source )or make) the parts, I can easily do so.  

Question: can I buy the parts for this?  Maybe buy the drum, if not the individual strips and screws?  If not, anyone know the screw type and size?

Here's a pic: