CO Gandy Dancer I found this circuit representation of the Bachmann mystery board in another very informative thread: <http://cs.trains.com/mrr/f/88/t/181314.aspx?sort=ASC&pi314=1> posted by ATLANTIC CENTRAL. I'm pretty sure you guys contributed to that exchange as well. I think I've got this mystery board figured out now and, thanks to you all, I have more than one option to consider. I'll ponder all this as I gnaw on my bone. Thanks!
I found this circuit representation of the Bachmann mystery board in another very informative thread: <http://cs.trains.com/mrr/f/88/t/181314.aspx?sort=ASC&pi314=1> posted by ATLANTIC CENTRAL. I'm pretty sure you guys contributed to that exchange as well.
I think I've got this mystery board figured out now and, thanks to you all, I have more than one option to consider. I'll ponder all this as I gnaw on my bone. Thanks!
This is the diagram larger. It was a new Bachmann USRA standard tender for a loco with a 12 volt light bulb. The circuit was to dim the headlight in reverse if anyone caan trace out the circuit.
Please note, the Bachmann cap/inductor layouts are different for almost every loco. Steam or diesel. The constant is, two inductors with one to three caps. Some have the caps on the motor, inductors on the PC board. Some inductors on the motor with caps on the PC board. Some caps and inductors on the PC board. In a couple sound value locos, the caps/inductors hidden under the loco cab for steamers.
My 4-6-0 with on board Tsunami sound had five caps. Three caps I traced out that where tied to the inductors.
Bachmann has come a long way from years ago but they are still inconsistent with their loco wiring. This does confuse thosse who are not familiar with electrrical wiring as used in DCC.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
I have done the plug and hardwire versions. It is much easier to do the plug and snip the caps off. A tuned circuit needs caps and inductors. The two inductors will be a moot issue with the caps gone.
Some PC boards have what looks like two green resistors for the 4.7 micro-henry inductors. Most never take time to check the colored bands to see what the device is. Many are still stuck in the DC loco era.
What happens if you take the board out and just wire in the decoder? Nothing - it just works better. You do have to add dropping resistors if the lights in that model are LEDs, and the decoder doesn;t already have current limited outputs. You also gain a lot more room to fit a bigger speaker and enclosure. And it does away wuth the annoying capacitors that cause issues with smooth operation - not having one to examine closely, it's some of those on the lower left, C1, C2, C3.Maybe all 3. Need to see which ones are across the motor. If you DON'T remove the board, definitely remove the capacitors.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
CO Gandy Dancer Previously posted . . . Here's a photo of what I'm dealing with: a Bachmann HO scale SP 2-8-0 "DCC Equipped"
Previously posted . . .
Here's a photo of what I'm dealing with: a Bachmann HO scale SP 2-8-0 "DCC Equipped"
OK, so I email the above photo to the elves at Bachmann asking what the circuit board *does* in one of their so-called DCC ready/on-board locomotives. After waiting several days the polite answer I got was (paraphrased) "for DC you plug in a DC plug; you plug in a DCC decoder into the 8-pin receptacle . . ." And thanks to everybody's help in this forum I already knew that.
And now I'm like a junk yard dog with a new bone to chew on: I still don't know what *function* the Bachmann board in the above picture fulfills. What happens if you carefully rip out (er, remove) the board and directly wire up the DCC decoder according to the established standard(s)?
Great - all the lights went off at the same time!!! Joe, between what you and "woodone" just put up everything came into clear focus - especially cutting the shrink wrap. I had no idea there might be a 9-pin JST lurking under there!!!
For my next challenge - unrelated to but enabled by this one - I have to figure out the options for a decent speaker installation into a Bachmann HO medium Vanderbilt tender.
You boyz have been a GREAT help, thank you very much!!
Mike
Tsunami decoder # 826101 and adapter # 810135. Cut back the plastic wrap on the end of the decoder with the 9 wires sticking out. Gently pull the part the wires go into off the decoder. The adapter then plugs into this location.Look at the bottom of the tender. There should be a round whole in the middle. If there this is where the speaker goes. A 1" speaker will fit. You have to remove the PC board to get to this spot. Joe
From the photo you posted it looks like you have removed the Bachmann decoder already. Is this correct?
If you are going to use a Tsunami TSU 1000 sound decoder you will have to use a 9 pin to an 8 pin JST adapter harness.
This means tha tyou will have to cut the 9 pin plug and wire off the Tsunami and plug in the addapter harness. Plug the 8 pin plug into the socket on the locomotive ahd hook up the speaker wires to a speaker and you should be set to go.
Take a look at this site and information about the Tsunami. Scrool down a bit and it showes how to install the 8 pin adapter harness. http://www.mrdccu.com/curriculum/soundtraxx/tsunami.htm
Thanks. I think I'll give the folks at Tsunami/Soundtraxx a call to see if they can help me unravel all these mysteries, they're just over the hill from where I live. I know everyone means well but there seems to be some conflicts of advice. I'm sure much of the "conflict" comes from my "noob" status as a DCC geek.
Failing everything else, since I'm not a purist (yet), I may just fall back, punt and just plug in an MRC #1608 Sounder - problem solved.
Sorry. I thought we where talking about a GP7.
Go to one of the links I just posted. A picture is worth a thousand words. The TSU1000 comes with a nine pin connector you can remove and plug in a 9 pin to 8 pin adapter.
You can also solder the seen wires to a 8 pin plug and just plug in the 8 pin connector.
I thought you had seen these links here before. Store those links I just provided and do a lot of reading.
Cut out the capacitors on the PC board for the Bachmann. SOP.
modelmaker51 The Tsunami comes with an 8 pin plug already attached. If the Bachmann board has an 8 pin socket, you just plug in the Tsunami and the bachmann decoder will be bypassed. You don't snip the wires, you unplug them, then you hard wire the Tsunami to the bBachmann wires. It's not difficult.
The Tsunami comes with an 8 pin plug already attached. If the Bachmann board has an 8 pin socket, you just plug in the Tsunami and the bachmann decoder will be bypassed.
You don't snip the wires, you unplug them, then you hard wire the Tsunami to the bBachmann wires. It's not difficult.
Getting more confused by the minute . . . I've never seen any Tsunami product with an 8-pin plug already attached. If I did get find one to plug in how would the Bachmann decoder know something else is plugged in and be quiet and not go stupid or spewing forth smoke? I didn't find a discussion of any interface controls like this in the NMRA DCC standards literature.
Where are these wires that get unplugged and why would I want to solder them to the Backmann wires? Wouldn't we want to ditch the Bachmann unit? Gahh
Here is the diagram from the Bachmann site for thee GP7. Little plastic fittings secure the wires to the PC board. There does not seem to be a 8 pin connector. You might be able to use those plastic clips for a light board Tsunami.
Some hardwire the TSU1000 and solder splice all the wires.
http://www.bachmanntrains.com/home-usa/dwg/dwgs/H624X-EXPLODEDVIEWII.pdf
IMPORTANT, you will need a 1k resistor if the loco has LED's.
You will need to find room for the Stay Alive capacitor.
If there are any capacitors attached to the motor leads, cut them out. A couple diesels I had where like that. They will be a yellow blob with two wires.
http://www.soundtraxx.com/choose/step3.php?t=ho&s=Bachmann
Looks like a 28mm speaker will fit in the oil tank. Cut a piece of new coffee filter to fit between the speaker and perforated speaker grill. The speaker magnet will pick up particles that are magnetic.
Someone at the Bachmann site has done a sound install with a GP9. Go look at the HO forum.
Below is what SoundTraxx recommends. It is a lightboard type decoder. I have used the TSUAT1000 and I needed to use resistors for the LED's.
CO Gandy Dancer ba&prr snip . . . If they are the newer diesels with DCC on board or DCC ready, you can use an 8 pin decoder. I have the new GP7 that I replaced the decoder board with a Tsunami Thanks for all the replies!! By "use an 8 pin decoder" do you mean put an 8-pin plug on, say, a Tsunami and just plug it into the existing receptacle leaving the Bachmann in place? This sounds counter intuitive: DCC address/programming issues; smoke, etc. And if you replaced the decoder board completely you snipped all the wires and removed the Bachmann unit, hard wiring the Tsunami into the wire harness? My sense is the only thing the in-place receptacle is good for is inserting a plug that permits DC operation . . . ?? (I haven't yet figured out how to attach a photo from my PC into this thread . . .) Mike
ba&prr snip . . . If they are the newer diesels with DCC on board or DCC ready, you can use an 8 pin decoder. I have the new GP7 that I replaced the decoder board with a Tsunami
snip . . . If they are the newer diesels with DCC on board or DCC ready, you can use an 8 pin decoder. I have the new GP7 that I replaced the decoder board with a Tsunami
Thanks for all the replies!!
By "use an 8 pin decoder" do you mean put an 8-pin plug on, say, a Tsunami and just plug it into the existing receptacle leaving the Bachmann in place? This sounds counter intuitive: DCC address/programming issues; smoke, etc.
And if you replaced the decoder board completely you snipped all the wires and removed the Bachmann unit, hard wiring the Tsunami into the wire harness?
My sense is the only thing the in-place receptacle is good for is inserting a plug that permits DC operation . . . ??
(I haven't yet figured out how to attach a photo from my PC into this thread . . .)
Use Photo Bucket. Most here use Photo Bucket for attaching photos.
I have not looked at all the Bachmann diesel diagrams. I do know some have no eight pin plug. Go to the Bachmann site and look at yours. Better yet, just remove the shell and see what you have instead of guessing.
I suspect you will have remove the present PC board and hardwire a TSU-1000 or a light board type decoder which needs no plug. Just solder the wires. Use a 1 k 1/4 watt resistor if the loco has LED's.
I have done both but not in a Bachmann diesel.
If you are new to DCC and sound, it most probably will be somewhat difficult if you have not soldered before. Easy installations are usually because the users has experience.
Below is a link you should keep and do a lot of reading about DCC and Tsunami sound.
http://www.mrdccu.com/curriculum/soundtraxx/
This link is barely the tip of the ice berg when it comes to DCC and sound. there are other DCC/sound companies and many different variations on DCC and sound installs. Some with Bachmann diesels have to do some frame milling. I had to with the Bachmann 44 ton, HO scale diesel that I put a LokSound in. Hadrwire.
Forget two decoders until you have some DCC experience.
Jay
C-415 Build: https://imageshack.com/a/tShC/1
Other builds: https://imageshack.com/my/albums
Go to Bachmann's web site. They have an Ask the Bach-Man forum. Sign up if you haven't already. Do a search for GP7 sound install by BAPGUY. I posted 2 photos and a discription of how I added a sound decoder to this loco. Joe
If the loco has an 8 pin decoder you remove the decoder and plug in the new 8 pin decoder in its place. On the decoder plug I believe the orange wire is pin 1. This must go in the whole for pin 1 on the board that has a 1 or dot by it. Other wise the loco won't run right. What locos are you plan on adding decoders to? Joe.
What Bachmann engines? If they are the newer diesels with DCC on board or DCC ready, you can use an 8 pin decoder. On the steam locos that are the newer DCC on board or DCC ready, they also have an 8 pin socket. I have the new GP7 that I replaced the decoder board with a Tsunami
It would help if we knew what scale you're asking about. Assuming HO scale, if it's a steam engine with the decoder in the tender, there should be plenty of room for a Tsunami or LokSound Select decoder to replace the Bachmann decoder, which has an 8-pin plug.
I'm in the process of installing a LokSound Select into a Bachmann 4-8-4 and will be able to simply remove the Bachmann decoder from the socket, plug in the LokSound, and connect two speakers, because there's plenty of room inside the tender.
You would have to wire in the Sound Bug. It is only a plug-in for certain Digitrax decoders. It's not a difficult wiring job. However, it's not the highest-quality sound, and you would be much better off with a Tsunami or Loksound for performance. The difference really is ear-popping.
Also, there are programming issues when installing two dissimilar decoders in the same engine. You really need to program the Sound Bug before you install it.
It takes an iron man to play with a toy iron horse.
You can add a sound only decoder (the Soundbug from Digitrax) or replace the non-sound Bachmann decoder with a drop in replacement or rip out the Bachmann and hardwire in a new sound decoder. I would go with option 2.
I thought I was posting a reply to a similar flavored thread discussing Backmann decoders in DC mode. Sorry.
Hello. I'm making the step to DCC as well. I don't want to be thought of as hijacking this thread but I have a directly related question:
With the Bachmann DCC decoder factory installed, if you want to add sound what are the options? 1. Plug a sound decoder (aren't they a full DCC encoder anyway?) into the 8-pin receptacle and retrofit a speaker? 2. Rip the Bachmann decoder out completely and retrofit a complete DCC decoder/sound system?
Thanks. Mike