DCC sound fitted Bachmann 37 wire adrift. Help please!

[Tim Hall]

A couple of months ago, I bought a Bachmann 37710 (32-390SD) 2nd hand on eBay from a private seller selling it for "an elderly relative", to run on my DC only layout. I bought this rather than a new one for a similar price as it's weathered, which as far as I can tell is not available commercially.

On testing it, I discovered that it was DCC sound fitted, which took me by surprise. The packaging clearly is for a DCC ready loco, but there's a piece of paper with the details of which DCC control does which (making me think it was mispackaged in the factory). Running it on DC obviously the sounds were limited, and I ran it a few times over a period of a couple of weeks to see if I was going to keep it as a novelty item. I had pretty much decided to sell it on as the sounds didn't particularly impress me, when it stopped running. It still does all the sounds it did, but wouldn't move. On opening the loco, I discovered a wire adrift (see photos).

 

I want to sell it as a runner ideally, with a full and honest description of its history. I don't think I should try to return it to the seller due to the time elapsed, use I've given it and the fact that they hadn't sold any other railway items.

 

So I would greatly appreciate help. Does anyone know where the wire needs to be reattached (probably)? Can it be done without soldering (almost certainly not)? Do you know anyone who could repair it (hopefully)? The offending wire can be seen pointing to top left in the first picture.

 

Sorry this is so long, but it's quite a complicated saga. As they were selling out, I bought a new DCC ready one, rather than faff around trying to remove the sound from the currently faulty sound fitted one, and although unweathered, it's lovely!

 

Thanks for wading through this tome.

 

 

[34theletterbetweenB&D]

What you have there is a previous owner's modification of what was at least a 21 pin DCC ready model. (Can you trust that it is definitely what originally came in the exterior packaging? Possibly one of the Bachmann tractor cognoscenti can advise. I get suspicious with this degree of modification, the mechanism may well be from a different Bachmann 37 for example.) Instead of using a 21 pin decoder, the owner has soldered in a wired decoder (type unknown) on a  scheme of his own devising. That's immediately a problem for the repair, as first you have to understand what has been done.

 

Since the sound still works, but there is no motor power, almost certainly that unattached wire needs to go to one of the motor terminals, and soldering most likely will be required. First step is to carefully track the wiring to the motor terminals to determine which terminal has no connection, in order to restore it. But to do this without a DCC system to use after the repair in 'programme track' mode as a safe check is inadvisable; a wrong connection will burn out the decoder if put on track power DC or DCC.

 

(Fairest way to sell it on would be a description on the lines of Bachmann XYZ in good mechanical and appearance condition, with a very unorthodox sound decoder installation - name decoder type if the paper has that information - hard wired directly to the 21 pin decoder socket. It will find a buyer sufficiently discounted.)

Edited August 22, 2020 by 34theletterbetweenB&D
clarification

[Tim Hall]

7 hours ago, 34theletterbetweenB&D said:

What you have there is a previous owner's modification of what was at least a 21 pin DCC ready model. (Can you trust that it is definitely what originally came in the exterior packaging? Possibly one of the Bachmann tractor cognoscenti can advise. I get suspicious with this degree of modification, the mechanism may well be from a different Bachmann 37 for example.) Instead of using a 21 pin decoder, the owner has soldered in a wired decoder (type unknown) on a  scheme of his own devising. That's immediately a problem for the repair, as first you have to understand what has been done.

 

Since the sound still works, but there is no motor power, almost certainly that unattached wire needs to go to one of the motor terminals, and soldering most likely will be required. First step is to carefully track the wiring to the motor terminals to determine which terminal has no connection, in order to restore it. But to do this without a DCC system to use after the repair in 'programme track' mode as a safe check is inadvisable; a wrong connection will burn out the decoder if put on track power DC or DCC.

 

(Fairest way to sell it on would be a description on the lines of Bachmann XYZ in good mechanical and appearance condition, with a very unorthodox sound decoder installation - name decoder type if the paper has that information - hard wired directly to the 21 pin decoder socket. It will find a buyer sufficiently discounted.)

Thanks for that, yes selling it that way is an option. I do have a 30 second clip of it running and making noises. There were two identical bits of paper in the box referring to DCC operation. Is this the standard Bachmann one? I enclose a close up of some of the electronic gubbins. 

Edited August 22, 2020 by Tim Hall
Added extra photo

[Pete the Elaner]

12 hours ago, Tim Hall said:

Thanks for that, yes selling it that way is an option. I do have a 30 second clip of it running and making noises. There were two identical bits of paper in the box referring to DCC operation. Is this the standard Bachmann one? I enclose a close up of some of the electronic gubbins. 

 

 

 

Hi,

 

That may well be Bachmann's function list, but if it was an original decoder, surely it would have simply been plugged in to the socket?

I would prefer to buy a socket & solder the chip to that, but I seem to be in a minority of modellers who consider de-conversion or future upgrading. (I would also rather do soldering away from the model where possible.)

 

Reading the decoder manufacturer/decoder type from a program track would be useful, as would playing all the sounds to confirm the list is correct, but these options are unavailable to you.

[34theletterbetweenB&D]

15 hours ago, Tim Hall said:

...I do have a 30 second clip of it running and making noises. There were two identical bits of paper in the box referring to DCC operation. Is this the standard Bachmann one? ...

Much as above, you are rather stuck at this point. Do you know anyone local with a DCC system prepared to help? Alternatively a model railway dealer able to offer DCC services?

[Tim Hall]

4 minutes ago, 34theletterbetweenB&D said:

Much as above, you are rather stuck at this point. Do you know anyone local with a DCC system prepared to help? Alternatively a model railway dealer able to offer DCC services?

No, most of my friends are DC only or 1:12 scale modellers, and my local dealer doesn't do repairs these days (they lost the last loco I gave them for over 4 years (only got it back last month)). 

[Baldy]

Tim. Could you post another couple of photos? I think the loose wire is red (maybe wrong as I am slightly colour blind). If so, and wire is coming from decoder, I think it is the right hand track connection which maybe should be soldered to top right hand pin (opposite pin labelled as number 1). However your final photos seems to show black wire having two wire connections to pin below. I am not sure why black (or red) would need two wires soldered to pins but additional photos may help. Could you show a photos looking where other end of black wire goes if there is a second wire from pin other than black wire to decoder. Would also be useful to see a close up of the black wire to pins, and pins right next to it to see if red wire is soldered to any of pins. I am not a dcc expert but it may help me or someone with more knowledge. 

[Tim Hall]

19 minutes ago, Baldy said:

Tim. Could you post another couple of photos? I think the loose wire is red (maybe wrong as I am slightly colour blind). If so, and wire is coming from decoder, I think it is the right hand track connection which maybe should be soldered to top right hand pin (opposite pin labelled as number 1). However your final photos seems to show black wire having two wire connections to pin below. I am not sure why black (or red) would need two wires soldered to pins but additional photos may help. Could you show a photos looking where other end of black wire goes if there is a second wire from pin other than black wire to decoder. Would also be useful to see a close up of the black wire to pins, and pins right next to it to see if red wire is soldered to any of pins. I am not a dcc expert but it may help me or someone with more knowledge. 

Looks peachy coloured in the flesh, but I'll nip up to the attic very soon. Thanks

[Tim Hall]

A few rather poor close ups. I've temporarily removed the black tape from the chip in case that helps. Looking at the way it's stuck to the chassis block, and the way the speaker is stuck to the roof, I'm inclined to agree that it's not factory fitted, looks a bit messy.

[34theletterbetweenB&D]

As rendered on my PC the unconnected wire is orange, as compared to the two red wires in the same view. Orange wire is motor supply, and that being unconnected is consistent with the problem reported in the OP:

On ‎22‎/‎08‎/‎2020 at 13:42, Tim Hall said:

... it stopped running. It still does all the sounds it did, but wouldn't move. On opening the loco, I discovered a wire adrift ...

That the sounds are still playing means the decoder is receiving track supply.

 

The problem in trying to assist is that I cannot tell from the photographs where the motor supply connection has broken, and reconnection without the ability to test on DCC programme track is in my opinion inadvisable.

[Tim Hall]

Yes, it's orangy/ peachy. 

 

No, I have no intention of randomly poking the loose wire in various orifices (orifi?) on the off chance I make the correct connection. That way lies madness!

[Nigelcliffe]

If you dig out the manuals for an ESU LokSound V4 decoder, then the wiring diagram is shown on page 15.   The "orangy/peachy" wire is one of the motor feeds, in the correct place on the decoder.  The other motor feed is the grey at one end.  

So, clearly the motor wire has come adrift from the motor.   Find the motor in the chassis, and reconnect the wire.  

 

The MTC21 pin out is also in the manual (page 13).  On your loco PCB, with the label next to socket so the writing is the right way up, the motor connections are on the right hand side.  Counting down from the top, on RHS, the pins are as follows, assuming installer used the correct colour conventions :  Track Right (red),  Track Left (black);  no-connection ; Motor Right (orange) ; Motor Left (grey).    So, your broken connection is most likely alongside the grey wire.  

 

Check all the above in the manual to be confident about it before soldering things.   

 

It looks like some sort of one-off wiring job to fit the decoder.  Don't know why someone would solder all the wires in when they could have just bought the MTC21 pin version of the decoder and plugged it onto the socket.  Equally, don't know why they didn't also wire the speaker via the loco PCB.  But some folk are just weird when it comes to wiring...   

 

 

- Nigel

[Tim Hall]

2 minutes ago, Nigelcliffe said:

If you dig out the manuals for an ESU LokSound V4 decoder, then the wiring diagram is shown on page 15.   The "orangy/peachy" wire is one of the motor feeds, in the correct place on the decoder.  The other motor feed is the grey at one end.  

So, clearly the motor wire has come adrift from the motor.   Find the motor in the chassis, and reconnect the wire.  

 

The MTC21 pin out is also in the manual (page 13).  On your loco PCB, with the label next to socket so the writing is the right way up, the motor connections are on the right hand side.  Counting down from the top, on RHS, the pins are as follows, assuming installer used the correct colour conventions :  Track Right (red),  Track Left (black);  no-connection ; Motor Right (orange) ; Motor Left (grey).    So, your broken connection is most likely alongside the grey wire.  

 

Check all the above in the manual to be confident about it before soldering things.   

 

It looks like some sort of one-off wiring job to fit the decoder.  Don't know why someone would solder all the wires in when they could have just bought the MTC21 pin version of the decoder and plugged it onto the socket.  Equally, don't know why they didn't also wire the speaker via the loco PCB.  But some folk are just weird when it comes to wiring...   

 

 

- Nigel

So is that definitely the type of decoder? That's very useful. Unfortunately, I don't solder, but it does help.

[Kaput]

Can't tell 100% from the pictures but it looks like the actual wiring to the PCB is unchanged from the factory therefore the easiest and most straight forward option for a DC user is to unsolder all the wires from the DCC socket and fit a blanking plug.

However if the previous owner done all this as an attempt to mod the lights for independant control then the actual PCB connections might have been altered meaning the above idea might not work.

 

Note: unsoldering the wires doesn't really require soldering skills, just a soldering iron and a reasonly steady hand. If unsoldering is completely and totally out of the question just cut the wires as close to the PCB/socket as possible with the smallest cutters you can get.

[beejack]

So from the picture this looks like a loksound v4.

The orange cable should be connected to the vacant solder pad next to the red cable.

 

If the solder pad is damaged and you have a multimeter you can find which pad on the reverse side is connected to the damaged pad and solder the cable to that pad instead.

 

Once you know it is all working again you could always desolder the decoder from the pins and fit a blanking plate. 

Sell the decoder and recoup some of the cost for the loco.  V4 decoders still fetch a good price secondhand.

 

[Tim Hall]

8 hours ago, beejack said:

So from the picture this looks like a loksound v4.

The orange cable should be connected to the vacant solder pad next to the red cable.

 

If the solder pad is damaged and you have a multimeter you can find which pad on the reverse side is connected to the damaged pad and solder the cable to that pad instead.

 

Once you know it is all working again you could always desolder the decoder from the pins and fit a blanking plate. 

Sell the decoder and recoup some of the cost for the loco.  V4 decoders still fetch a good price secondhand.

 

Thanks for that. I don't have a multimeter or a soldering iron, a), but it's good information. Two of you agree that it's a V4 decoder, and where the stray wire needs to go.

[Tim Hall]

8 hours ago, beejack said:

So from the picture this looks like a loksound v4.

The orange cable should be connected to the vacant solder pad next to the red cable.

 

If the solder pad is damaged and you have a multimeter you can find which pad on the reverse side is connected to the damaged pad and solder the cable to that pad instead.

 

Once you know it is all working again you could always desolder the decoder from the pins and fit a blanking plate. 

Sell the decoder and recoup some of the cost for the loco.  V4 decoders still fetch a good price secondhand.

 

Thanks for that. I don't have a multimeter or a soldering iron, a), but it's good information. Two of you agree that it's a V4 decoder, and where the stray wire needs to go.

[Tim Hall]

Thanks for all your comments. I've just discovered that although my local dealer no longer does repairs, a former employee of theirs does, so I've emailed him on the matter.

Hopefully he'll be able to assist.