Hello world,
I recently ordered a replacement chassis for my 4-6-0 big hauler steam engine.
Hook ups to the electronics board were very easy, and I confirmed that the locomotive runs well in forward and reverse.
I've documented my rebuild so far. It's on YouTube here and covers the written background info below.
Background and current state:
I'm looking for advice on how to reestablish connection of smoke lights and sound. My locomotive shell came off of a generation 4 chassis so I'm assuming late 1990s to early 2000s model (based on posts by Loco Bill and others). It has a switch for the smoke unit behind the smoke box door. One black and one red wire lead from the switch, and was previously soldered to the motor block in the old chassis. A small black and white wire lead out of the middle of the switch to the headlight.
As for the chuffing sound, no chuffing sound is heard even with 9V battery plugged in where it's supposed to be in the tender and the proper G2 plugs in their respective ports on the electronics board.
Questions/advice requested:
For the lights and smoke, should I simply splice the red and black wires into the track pick up wires before they reach the board? It was suggested that I also solder a J2 pigtail immediately onto the board where the power enters the board. Is there any other thing I should consider, and is it possible to completely separate both components so that they can be controlled by the PNP board?
For the sound and the tender, I am fine restoring the factory, plain old chuff sound. Should I open the tender and bypass any electronic boards that are there and instead, reroute the wire that connects to the locomotive directly to the speaker unit?
Thanks, and happy rails. (Original post edited to remove some incorrect references).
-nrrtx86
https://youtu.be/HPBaNU6aH4k?si=AF1v0wqMiBWmlaFH
Sigh, you have a lot of questions, but you actually need some fundamentals.
First, that is not a PNP board, PNP normally means you can plug in a decoder. So, you want to stop using that terminology just so you don't get a lot of strange suggestions that will only confuse you.
Your questions about how to connect various things really depend on where you are going with this... if your goal is to run just plain DC to the rails, that is one set of answers.
But if you will fit some sort of control system, then there is a different set of answers
And if you are going battery, some more answers/suggestions.
On top of this, I'm the kind of guy that does not answer "just tell me how to do it, I don't want to understand why"
So, some education of how the basic components work is also in order.
Therefore, I suggest the best way to proceed is do your "look ahead" and determine your final destination, and we could proceed in that direction.
Now, this is just my personal opinion, and my "rules"... I have a very large and detailed web site that takes maintenance and I get a lot of requests for help, so I don't have the luxury of going in several directions at one time.
There's many other people with other motives/strategies/time allocation, and they should chime in here too.
Quote from: nrrtx86 on September 01, 2025, 10:32:08 AMHook ups to the plug-in play (PNP) board were very easy
As Greg said, with a 4th gen loco, your tender doesn't have the 'official' pnp board. But your tender should have the electronics and speaker for the old chuff sound (easy to check.)
The chuff trigger used to be a drum on the front axle, which was wired to the connector at the back of the loco. It's visible on your video at 6:30. I also note the new chassis has the same connector on the back for the tender chuff, so you need to confirm (a) that your tender electronics work [short between the 2 wires at the front which lead to the chuff drum, with the engine disconnected,] and (b) that the chuff drum works the same way in your new chassis.
I think you'll need a multimeter and to learn how to use it.
Thanks for your reply. I have modified my original post to remove rookie mistakes. Using my hobby to learn more about electronics. Gotta start somewhere.
DC operator/operations for now. My goal after chassis swap is to simply restore the old chuff, light, and smoke functions (if possible) all running DC track power. Later on, I plan to learn and convert to a full wireless protocol with battery power.
Quote from: Greg Elmassian on September 01, 2025, 04:00:19 PMSigh, you have a lot of questions, but you actually need some fundamentals.
First, that is not a PNP board, PNP normally means you can plug in a decoder. So, you want to stop using that terminology just so you don't get a lot of strange suggestions that will only confuse you.
Your questions about how to connect various things really depend on where you are going with this... if your goal is to run just plain DC to the rails, that is one set of answers.
But if you will fit some sort of control system, then there is a different set of answers
And if you are going battery, some more answers/suggestions.
On top of this, I'm the kind of guy that does not answer "just tell me how to do it, I don't want to understand why"
So, some education of how the basic components work is also in order.
Therefore, I suggest the best way to proceed is do your "look ahead" and determine your final destination, and we could proceed in that direction.
Now, this is just my personal opinion, and my "rules"... I have a very large and detailed web site that takes maintenance and I get a lot of requests for help, so I don't have the luxury of going in several directions at one time.
There's many other people with other motives/strategies/time allocation, and they should chime in here too.
Quote from: Fred2179 on September 02, 2025, 11:58:37 AMI think you'll need a multimeter and to learn how to use it.
Hi Fred, thanks for your reply. I checked the electronics with a multimeter and all seemed to be flowing as it should based on what I could tell and by following the paths.
I saw the suggestion of Loco Bill Canelos on another thread to short or jump the connection to test the tender speaker electronics. All I heard was a bit of a click, but I didn't hear the static "chuff" sound constantly. I assume I would hear it constantly since the circuit was fully closed and not alternating open close synced with the spinning drum on the axle.
So if they click is expected, then I believe the electronics are working fine if I should hear what sounds like constant radio static (constant chuff) then perhaps things aren't in working order.
just tap a couple of wires to make and break the connection... should sound like a 1960's AM radio off station.
If you're just going for DC track operations, then set aside the PNP board and simply wire as the older gen's. From chassis you will have two motor wires and two pickup wires, connect to shell wires just like Gen4 and earlier.
There is NO PNP board... he does NOT have one, he mistakenly called the "main board" a PNP board.
Realize there are more boards (possible) in the loco... he needs to download the wiring diagram from the site and work from that.
(you may have forgotten the chuff circuit, the flicker circuit, etc.)
The best thing is to go to the bachmann documentation, and find the drawing that matches what you have the best... then try to wire up in that way... (the parts diagrams usually have the wiring diagrams on the last couple of pages)
For reference about the part of this discussion about a Bachmann PnP board in the 4-6-0:
Only the newest version,which is version number 7, has a Pnp board installed in the tender.
I own,and have totally rebuilt, versions of the 4-6-0 from V2 to V7,and the V7 is the only one so far that has ever come with a factory installed PnP board from Bachmann.
The electronic sound system that was included in all versions from V1 to V6 is referred to by Bachmann as the PCB board.
https://estore.bachmanntrains.com/index.php?main_page=product_info&cPath=69_671_669&products_id=5290
This should dis-spell any further references to there being a PnP board in the earlier 4-6-0.
Thank you !
Actually there are SEVERAL pcb boards in the loco itself, so "the PCB board" is not a good term to use, (also it is grammatically incorrect, PCB board expanded is: "Printed Circuit Board board" board board?
The board he has is one that stays in the loco, not the tender.
Unfortunately, the only documents on the site are for the current version, not his... nor are the documents matching the chassis he purchased.
Since you have rebuilt older versions, you have encountered the boards in the loco, correct?
Greg
As I remember, there is only a small circuit board that is located in the back of the locomotive chassis.
It has two wires running from it to the sound drum on the front wheel axle.
The sound drum has a couple of metal strips built into it.
As this drum rotates on the front axle, these metal strips make contact with two metal contacts that are mounted inside the chassis.
There are two wires that (one red, one black) that run back to the small circuit board at the rear of the chassis.
This board has either one two prong plug for the tender sound (Standard Edition),or 2 two prong plugs(Anniversary Edition for the sound and rear light. Coal burners only ,as the wood burning Anniversary Edition models models usually don't come with a rear headlight. At least as far as I know, and I currently own 18 4-6-0 Big Haulers).
Bachmann calls their sound board in the tender a PCB.
If you click on the link for the tender flat on their parts department website, you'll see what I mean.
Therefore, that's what I am calling it as a common referent point.
The Big Hauler is a fairly simple locomotive to work on.
I have rebuilt at least 2 of the Anniversary chassis from the ground up using either new parts from Bachmann, or Ebay.
Matter of fact, I just bought and restored a #177 Denver & Rio Grande V4 locomotive.
I usually replace the older chassis on these with the newer Anniversary chassis, but this one runs very quietly, and is a strong puller.
So far, anyway.
I have a spare Anniversary chassis sitting in my closet right now, so I can pull it out and post some pictures of the working innards if you'd like.
It is a version 5.
As I understand it, the V6 does have a large circuit a board installed in the the front .but the V5 does not.
Of course, I haven't had an excuse to open up my one V6 4-6-0...at least not yet...
Later!
Mike
flicker board...
Quote from: nrrtx86 on September 03, 2025, 04:17:44 PMSo if they click is expected, then I believe the electronics are working fine if I should hear what sounds like constant radio static (constant chuff) then perhaps things aren't in working order.
You did find the volume control, which sticks out underneath? It has an 'off' position - fully anti-clockwise, I think.
Is there any better description/schematic for the G912X-PCB06-A card? Also, I may just be blind but is there a wiring diagram that is specific for the replacement chassis that Bachmann currently ships? I am not new to electronics but new to trains. (Looking at some of the other links on this post - very helpful).
I looked through the online documentation and all the things I've downloaded over the years, and no go on any wiring diagram.
So my advice is to forget this board, since there's no documentation to it, and just start wiring the loco like it was before.
That is, wire the track pickups to the motor (I'd even leave off the polarity switch, but you might want it if you mix in LGB with NA trains.
Then the lights, then the chuff circuitry, then the flicker board if you have it.
That is my advice to you...
If it was me, I would take the challenge to reverse engineer the board and find how it was wired (i.e. make a schematic) and then use it... but I am an electrical engineer and I like a challenge.
The board has got to be simple, and probably only a single layer, double sided board.
Greg
well?
Well I actually was able to use the board after watching the YouTube video at the top of this post and connecting the wiring for the chassis as he did.
No connections for smoke box, but was able to get the chuff sounds working using the tender connection using this method.
Here is a photo with wires connected. This allowed me to test the new chassis as received from Bachmann without cutting any wires
so I could confirm it was working when received. Screenshot 2025-09-23 at 6.15.22 PM.png
To get back to the question - I still don't have thw two wires hooked up for the smoker on the original cab. I suspect that this should be connected to the left SMK+ connector, likely with the red wire to the right. I was rather surprised that there wasn't at least a sheet
of documentation for that board since it is likely to be used to retrofit older trains.
Also would be nice to know where sort of connector is used on the board, and sources for the wire ends connectors that match (and a likely source for same such as Mouser or Digikey or Newark).
This is a very valuable source for chassis change The pcb board detail photo shows the process to be very straight forward. Looking at the board I see the smoke connection, but there are other potential connections that could be usefull as well. I am in a middle of a move to a new smaller home and have no access to my trains or the chassis which I keep in stock. By all means forum members seek out the other possibilities for using this PCB. It will be a valuable contribution tho this board, and thanks to all so far. Keep on exploring for those of us that will benefit from your contributions.
Cheers and Beers Loco Bill
so, I see a 3 pin connector for "sensor" which I assume it the 3 terminal optical sensor, and then I see 2 wires to "trigger" which would seem perhaps the original metal make and break contacts.
so where do these 2 sets of wires go in your installation?
I am a novice at hobby trains, but electrically knowledgable. This is the hookup on a bare chassis purchased as a replacement from
Bachmann a couple of months ago, which was sold with zero documentation of the PCB provided (or even installation information of same
with the chassis). The 4 cables were the only wiring on the new chassis, and I connected them up by following video on the first comment on this thread. There is no old generation parts on this - it was hooked up to test the new chassis prior to putting the old cab on top
of the replacement chassis. The only part moved over is the weight from the old chassis.
I need to call Bachmann directly I suspose and see if I can get any additional information. I am not seeing anything on their website
that documents this board.
https://estore.bachmanntrains.com/index.php?main_page=product_info&cPath=69_671_669&products_id=4094 is the chassis I purchased for
reference to replace one on a 90037 locomotive, for reference.
Looking at the PCB, I would expect the two wires labeled "Trigger" to go the the rear of the loco where the small PCB with on/off switch provides the connection to the "chuff sound board" in the tender. More appropriate name might be "Trigger Out". I can tell from the PCB that the chuff sensor (connector is 3-pin) is using some form of optical or hall-effect sensor. The circuity above the connecter is a DC/DC power supply needed to power (VDD) the optical sensor. In addition, near the Trigger connector is a Q1 and square 4-pin device that is probably a solid state relay mimicking the open/close contacts of the old chuff sensor. Since he has the new chassis the chuff sensor should be in place with the 3-wire connector attached. He then needs to connector Trigger to the locos rear "Sound" connector board. At this point, I don't beleive polarity matters.
seem the board can accept BOTH the old style make-break mechanical chuff contacts, AND the newer optical sensor unit
My question on post #20 was to determine what the heck was connected, it makes no sense to have BOTH of the "triggers".
Yes, if you look at the 4 pin device, it uses a transistor Q1 to connect to the 3 wire optical sensor electronics.
But I see no electronics relating to the sound unit/speaker...
perhaps this board was designed as a universal interface to new and old style electronics...
Since this post was from back in September, you may have already found your answer on the connector types for this board but in case no one else has responded yet, these are called JST Connctors. This stands for Japan Solderless Terminals. If you have the patience to search for them, you can go to one of the huge Electronic stores such as Mouser or Newark among others. I had some on hand from another project from several years ago but the tricky part here is that Bachman uses several different sizes of JST's along with different quantity of pins on these. I went to Amazon and after measuring the spread between each pin with digital micrometers, I ordered sets of each size to have on hand for future projects. There are so many sizes to choose from but Amazon has sets of each size relatively inexpensive. You can buy anywhere from 1.5 mm to 2.54 mm and any2here in between.
Quote from: deritchie on September 23, 2025, 06:31:45 PMTo get back to the question - I still don't have thw two wires hooked up for the smoker on the original cab. I suspect that this should be connected to the left SMK+ connector, likely with the red wire to the right. I was rather surprised that there wasn't at least a sheet
of documentation for that board since it is likely to be used to retrofit older trains.
Also would be nice to know where sort of connector is used on the board, and sources for the wire ends connectors that match (and a likely source for same such as Mouser or Digikey or Newark).
Quote from: deritchie on September 23, 2025, 06:31:45 PMTo get back to the question - I still don't have thw two wiresQuote from: deritchie on September 23, 2025, 06:31:45 PMTo get back to the question - I still don't have thw two wires hooked up for the smoker on the original cab. I suspect that this should be connected to the left SMK+ connector, likely with the red wire to the right. I was rather surprised that there wasn't at least a sheet
of documentation for that board since it is likely to be used to retrofit older trains.
Also would be nice to know where sort of connector is used on the board, and sources for the wire ends connectors that match (and a likely source for same such as Mouser or Digikey or Newark).
hooked up for the smoker on the original cab. I suspect that this should be connected to the left SMK+ connector, likely with the red wire to the right. I was rather surprised that there wasn't at least a sheet
of documentation for that board since it is likely to be used to retrofit older trains.
Also would be nice to know where sort of connector is used on the board, and sources for the wire ends connectors that match (and a likely source for same such as Mouser or Digikey or Newark).