bachmann dcc 4-8-4 sante fa

[train with no shame]

my 4-8-4 won't move . i took the tender apart and inspected the encoder. i have voltage from the wheel trucks to the encoder "the green and blue wires" i have it addressed to # 6 on the ez commander. with the tender on the tracks and the engine off the tracks .and plugged in "the 2 prong and 4 prong plugs . is there sapposed to be voltage across the drive wheels on the engine .without it being on the tracks. i'm trying to figure out if i have a bad encoder . no lights wont move . im hoping thats the problem and not a burnt engine . i park it on a turnout on my layout .and was doing some work to my layout . and went to move it .and no responce ...... is there any other way i can check it . b-4 calling the ah-oh squad and taking it to the LHS. all the other locos are working fine . as i said b-4 i did have a couple of derails with it . thanks mark f

[richG]

You should have about 12 to 14 volts on the track using the AC scale on your multimeter, at least that is what I see on my DCC layout. This voltage will be applied to two decoder leads.
I sounds like your are reading resistance since the loco is off the track. There will be no voltage off the track.

Rich

[train with no shame]

i here what your saying .....i understand that ...i had my tender on the track both sets of trucks all 16 wheels on the track . i had voltage from the trucks of the tender to the encoder . i plugged in my engine while the tender was on the track and my engine was off the track laying upside down by the tender. off the track . i checked across the drive wheels of the engine . and had voltage . i didn't understand why i had voltage .  seeing if the wheels would turn and checking voltage from the plugs 2 prong and 4 prong to the  engine . does the engine pick up voltage off the track or does the tender pick up power from the wheel trucks. i see the brass on the steel wheels that pick up power on the tender . where does the engine get its power to drive it . even the light on the tender is dead .  im wondering if my encoder is bad .and not addressing and not letting my engine power and lights not working .....

[train with no shame]

im going to reword this . i took apart the tender and had the i guess chassis on the track . the plugs were loose from the tender .just hanging . encoder still in place on the chassis of the tender... i put the engine beside the tender off the track upside down and plugged in the 2 and 4 prong plugs . to see if i was getting any voltage to the engine from the encoder. i addressed it to #6 .that is what i addressed it to . i turned up the throttle and then hit the function button and then button 10 for the lights .nothing . im trying to find out if my encoder is bad or if there is something wrong with my engine . i run a power plant and can't understand a toy ..... wow ...it ran 2 days ago .and today wouldn't move and no lights .     .......dead...... if there is any other way i can check it please let me know ..... if not ill take it to our LHS and have there tech look at it . im trying to learn of how the electronics work on the dcc equip locos . as this  is my 1st dead loco .instinc tells me go buy another one . i would like to fix this one. i understand the concept but not seeing the big picture  .....

[richG]

Yampa Bob has posted diagrams of the Spectrum wiring configurations.

The tender picks up voltage and sends it to the decoder. A pair of wires from the same two decoder connections, connects to the two pin connector for the engine. The drivers are connected to those two wires so you will see voltage on the drivers  with the loco off the track.

The four wire connector has two wires to send power to the motor and two wires to the headlight.

I strongly suggest, when Yampa Bob says something, pay attention. Now there use to be a commercial that sounded similar? Some people gloss right over his post.

Spend time reading messages, at least, in the General and HO sections. You never know when you will find useful information.

I do not use the EZ Commander so that is the best that I can do. Good luck.

Rich

[richG]

You might also take the meter probes and on the AC scale on the NMRA connector, touch pins 8, Red wire and 4, Black wire. Probe polarity is not important. You should see the track voltage using the AC scale on your meter. Make sure you touch only those pins with the probes. Don't slip and touch an adjoining pin at the same time.

If you have voltage there, the programming might not be correct or the decoder is no good.

There are a couple people here that use the EZ Command.

Since you see voltage on the drivers, that tells me the tender trucks are picking up voltage correctly.

Rich

[Chris350]

Have you tried readdressing the loco to 03 to see what happens?   By any chance did the engine come with a DC plug or jumpers that you could  put in the 8 pin socket to try the loco in straight DC?  Many DCC systems will run a DC loco on address 0.  As to engine electrical pick up, there ought to be wipers on the drive wheels supplying current in addition to the pickups on the tender trucks.  One more thought, can you verify that both tender trucks are oriented properly?  One ought to be picking up power from the right rail and the other ought to be picking up from the left.  It's possible that one is rotated and therefore it is not completing the circuit properly.  If you look carefully, you should be able to see that one side of each tender wheel set is insulated.  I've reversed tender wheels before and if I recall they don't show as a short, they just don't work.

PS I have had a couple of very interesting conversations with one of the owners of my favorite local shop.  He's a programmer, and understands the nuts and bolts of DCC.  It's interesting and not as straightforward as one might expect....


PPS YB's posting referenced to this is not showing.  Or did he not post to this thread in whic case I'm not seeing something I ought to ... No big deal either way.

[richG]

Do a search in the forums for tender wiring. I tried and got an answer but could not link the search results to this thread.
Maybe if I selected just one result I could. Do not know.

Rich

[Yampa Bob]

Mark,

From the symptoms you describe, it sounds like the 4 pin plug is not completely inserted into the tender. It may have come partially unplugged due to the derails you mentioned.  Check to make sure both the 2 pin plug and 4 pin plug are inserted into the tender connection as far as they will go.

Here is a link to my thread on the tender wiring. Your tender is different, but the wiring scheme is typical for most Bachmann locomotives. Please read it thoroughly through post #6.

http://www.bachmanntrains.com/home-usa/board/index.php/topic,7439.0.html

Notice that both the loco pickups and the tender pickups provide redundant power to the DECODER. (To be technically correct, the device in the tender is called a "Decoder", not an "Encoder")  Encoding is performed by the controller, interpretation of the coding is done by the Decoder. 

If all pickups are functional, then you will have power to the loco motor and lights (via the decoder) with the tender on the rails and the loco off the rails as you describe.

It is also possible that the decoder has lost its address due to a short caused while placing the loco on the tracks. Try re-programming the loco as mentioned. You may have to use the "unknown address" instructions at the bottom of page 3 in the manual.

Regards

[Jim Banner]

Power pickup is from the tender wheels AND from the locomotive wheels.

That DCC device in the tender is a "decoder."  The "encoder" function occurs in the command station when it converts controller information, such as throttle position, to DCC signals.

When your locomotive's motor would not work, did you test the headlight?  If it worked before but quit working when the motor quit working, your locomotive's decoder has probably lost its address.

During derails, or accidental track shorts, decoders will sometimes lose their addresses.  Try reprogramming to a new address, using the instructions for programming a decoder with address higher than 10.  These directions are on the bottom of page 3 of your E-Z Command manual.  There is no guarantee that this will fix your problem but at least it will not hurt anything.

Jim

[train with no shame]

thanks to all for help and suggestions . i will print out this thread and and let you know this afternoon what happens .i knew i was calling the decoder wrong . thanks for correcting me  gotta get some coffee . again thanks .

[train with no shame]

i did see voltage on the #4 & #8 wires on the decoder .i also tried readdressing and with no avail and hope nothing . i also checked the brass wipers on the tender trucks .and they looked good and tight to the wheels as i could see . also no loose or pulled wires from the pin connections and were properly seated . i will put the tender back together .and take her to the hobby shop and start with the decoder and hope this fixes my problem . and will read further on decoders and there functions so i can get a better understanding . thanks to all for the help and replying to my post . mr banner yampa bob mr satnik rich g and to all i do sit and read your post religiously as i have learned so much about this hobby .thanks again   regards mark f

[richG]

Hi Mark

Well, that is a partial solution. You did quite well so far. Unfortunately, DCC is not plug and play regardless of what the DCC companies say.
Stepping from the DC, Analog world into the DCC, Digital world is a big step as you no doubt have found out.
Ever try programming a VCR? I remember the days when you had to get up to change the volume and channel on the TV. Sometimes you had to pound on the TV case to get a better picture on the TV, or twist the coat hanger more.

Good luck. Hope to hear from you when you get the loco to run.

Rich

[train with no shame]

thanks rich hope to here and talk to you again . and yes i remember those days well . we had a turbine once that kept puking oil up threw the sump .and shutting down .went threw everything on the matrix .came close to pulling it from the encloser . went threw the pnid .everything . this older man from ge came down did some looking .and found one of the hoses was backwards on the return . the pnid was wrong on the drawing . just the simple things 1st . brought me back down to a level .of knowing my equipment .. thanks rich mark f 

[train with no shame]

oh and my type a personality gets me in trouble sometimes   lol thanks again . i will let all know   .going to drop it off today