I need to convert an HO Bachmann 44-ton locomotive from DCC to DC. Can anyone help me with how I need to reconnect the wires to allow DC operation, with reversing headlights?
just enable dc operation on a dcc controller, change cv 29, if it's not already enabled ..
Can't you just change CV 29 = 6?
If you don't have a DCC system, is their a train store, train show, train club, Christmas display nearby?
There is also a social platform, called Nextdoor, where people people post about things in their neighborhood, like need a dog sitter, or a painter, or I saw a lost dog.
Henry
COB Potomac & Northern
Shenandoah Valley
wvg_ca just enable dc operation on a dcc controller, change cv 29, if it's not already enabled ..
Well, dual mode decoders suck on DC, and don't work with all DC throttles.
See those seven wires going to the decoder? And the numbers on the circuit board.
Simply cut the decoder wires, and connect terminals/wires 8,1 and 2 together. And connect 4, 5 and 6 together. Ignore 7, cut it off flush so it does not touch anything.
Your engine will now run on DC just fine. The headlights will work in the direction of travel.
Sheldon
Also, I can't trace that circuit board from the picture, but if you can figure out which capacitor on the circuit board is the motor noise suppression circuit, and simply remove it, the slow speed performance of the loco will improve.
I think? it is the one marked C3, or, you may need to remove all four on this board?, but I don't have that loco or my notes handy right now to check. Just moved, lots of stuff still packed......
I run DC with Aristo Craft Train Engineer wireless radio throttles. They use PWM motor control and will not work with dual mode decoders, so I am well versed at removing decoders.......
Bachmann has used several different circuit boards in that loco, somewhere I think I have some notes.
Just a dumb question, but have you tried running it on DC 'as is'? Virtually all decoders in the last 10 years or so are set up to work fine on DC.
Otherwise, the "old fashioned way" would be to remove the decoder and light board completely. Connect the red wires from the trucks to the orange wire, and connect the black wires from the trucks to the gray wire. You'd then connect up headlights (LEDs or bulbs) to the red and black wires. You could add diodes to make the lights directional if you wanted.
wjstix Just a dumb question, but have you tried running it on DC 'as is'? Virtually all decoders in the last 10 years or so are set up to work fine on DC. Otherwise, the "old fashioned way" would be to remove the decoder and light board completely. Connect the red wires from the trucks to the orange wire, and connect the black wires from the trucks to the gray wire. You'd then connect up headlights (LEDs or bulbs) to the red and black wires. You could add diodes to make the lights directional if you wanted.
As I explained, there is no reason to remove the light board if you remove the decoder. The seven wires to the decoder correspond to the standard 8 pin socket and can be wired as I described to retain the directional LED lighting, just as if it had an 8 pin plug and jumper plug, and was sold as DCC ready.
And again, most dual mode decoders do not "work fine" on DC, especially on more advanced DC throttles.
Dual mode decoders do not run on pulse width modulated DC throttles, and even on simple power packs, their performance is often not as good as with the decoder removed.
Brother Sheldon, I think you are going to have to explain exactly why PWM, especially low-frequency or nonsinusoidal PWM, doesn't play nice with decoder circuits. Sometimes you have to educate 'em to 'get the message through.'
And I thought I had trouble having to keep repeating myself about dynamic augment...
I wasn't advocating removing the lightboard and decoder, just pointing out that was another alternative.
FWIW when I buy a new engine I normally give it a break-in run on DC before trying it on DCC. I've never had any trouble doing so using my old MRC Tech II or Tech IV powerpacks. Seems odd DC manufacturers would change things to not work well with dual-mode decoders when decoder-equipped engines are becoming more common, but I suppose there's some reason.
Your basic power pack like that is striahgt DC, or with an added sine wave pulse if the pulse power is turned on, or automatic in the case of some of them.
PWM is square waves. What else is square waves? Yes, the DCC signal. This confused decoders, they think they are on DCC track and won't respond, but in reality they are on PWM DC. PWM has a constant amplitude pulse (the peak voltage), it is the width that varies, the wider the pulse, the more 'on' time relative to the 'off' time and thus the higher average voltage. There aren't a lot of DC control systems that use PWM, but it does allow for smoother control than even a pulse power DC pack.
As for the capacitors, I'm pretty sure C3 adn C4 are both on the motor. The two components int he middle that look like resistors are actually inductors, they are in series with the motor leads and would need to be jumped with wire if removed, but if the caps are removed, the inductors cause no issues.
I have one of these locos, although mine has incandescent bulbs, but the circuit board is the same. It was the DCC Ready version, on those 7 wires on the side where the decoder is connected, there are a couple of metal tabs clipped on, bridging the appropriate terminals to allow the loco to run on DC. Were, since I installed a decoder. Mine's packed away too, but I'm pretty sure I clipped out both caps, C1 and C2 on this one I think are just to keep the LED from flickering. Eventually I will remove the factory board, to make enough room to put a sound decoder and speaker in it, and switch the lights to LEDs.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Overmod Brother Sheldon, I think you are going to have to explain exactly why PWM, especially low-frequency or nonsinusoidal PWM, doesn't play nice with decoder circuits. Sometimes you have to educate 'em to 'get the message through.' And I thought I had trouble having to keep repeating myself about dynamic augment...
There we have it, Randy explained it before I could get back on here.
When I still had some decoders on the property, and using my Aristo 10 Channel Train Engineer wireless throttles, I could have made some funny videos of locos just sitting in one place, trying to go forwards and backwards at the same time, the typical reaction of the inexpensive Bachmann decoders.
OR, of several Broadway Limited locos with sound that only had two speeds - Stop, and full throttle.........and a terrible buzzing noise as the throttle ramped up to get the loco to move.
Stix, why would manufacturers make such throttles? Well, for one thing they were invented before DCC........and they provide much better speed control them most "regular" DC throttles.
In fact your DCC decoder controls the motor in your loco with the same kind of signal. A DCC decoder output is a pulse width modulated throttle - but it expects a different kind of input from the rails.
Why do I use them, well, to get good speed control and a wireless throttle without installing decoders.
Randy, yes C3 and C4, I found my notes on that board.
The ones on the lighting side don't seem to have much effect either way, but removing the ones in the motor circuit will result in much better slow speed operation.
Yes, both with your PWN DC system and with DCC. Mine ran fine out of the box when tested on DC with my Railpoer 1370, but it ran horribly on DCC once I put the decoder in, until I removed those capacitors.
The ones for the LEDs shouldn't do anything with the motor drive, but it's possible they could interfere with DCC decoder lighting functions, since they use the same sort of PWM to dim the LEDs - though why you would put any special effects like blinking or gyralight on the one and only headlight I don't know.
Thanks for your specific instructions about removing the DCC decoder entirely, which is what I was hoping for. I have zero interest in DCC operation, after fumbling with it for over four years, with my actual modeling having come to a standstill. I am tired of the complexity, especially for my simple one-locomotive-only shelf layout. The only benefit is having sound, which has become kind of annoying.
Don Strack Thanks for your specific instructions about removing the DCC decoder entirely, which is what I was hoping for. I have zero interest in DCC operation, after fumbling with it for over four years, with my actual modeling having come to a standstill. I am tired of the complexity, especially for my simple one-locomotive-only shelf layout. The only benefit is having sound, which has become kind of annoying.
Don, you are most welcome, glad I could help.
I considered DCC several times, and have operated on a number of DCC layouts. Even helped design, build and wire a few.
My own layout goals are the polar opposite of yours, and yet I too find DC and no sound a better fit for me as well.
Take care,