Bachmann Railtruck conversion to Airwire, Zimo decoder and battery power

[Beddhist]

This is a first for me. I have never worked with any of the components.

To start with, I dismantled most of the truck to fix the known gear box problem, as per http://www.girr.org/girr/tips/tips8/bachmann_railtruck_tips.html#gearbox There is play in all the drivetrain components, so I wonder whether the diff will cause problems in the future. Lots of loose screws in the chassis were tightened.

Here is the chassis with all the gadgets that must be installed:



There is an Airwire Convrtr, a Zimo MX645 with the Galloping Goose sound preloaded and an ESU speaker. The battery is only for testing and will be replaced by something more compact later.

First step is to lose the circuit board. I simply cut off all the wires. I cut the pickup wires to the rear wheels flush with the deck. The speaker will probably sit over the slots in the centre, but there are some burrs from manufacture. 4 screws and the rear axle comes off, I then removed the pickups and everything that went with it. The burrs could now be removed with a sharp knife, so they won`t interfere with the speaker.

Next was a lot of wire stripping and soldering, a process made a little difficult because of my poor eye sight at close range, plus my fingers are not the most nimble. At this stage I didn`t wire the lights, as I don`t have any resistors on hand. After triple-checking all my connections I connected the battery and fired up the Tx. Result:

[youtube]http://www.youtube.com/watch?v=0DOo88okj6o[/youtube]

Hooray, no magic smoke and it works at the first try. First impressions: this is hard to control! Most of the time when I hit the stop button it just keeps going. Most of the time it ran off the end of the track. Sometimes pressing one function key activates the next numbered function. Most annoyingly, after pressing a function key you have to wait several secs before you can use another key. If you don`t it is ignored. At slow speed it runs jerkily. I don`t know whether this might improve over time.

Next is wiring the lights and then installing it all permanently, as well as re-assembling the truck.

Regards,
Peter.

 

[trammayo]

Is the control a keyfob? The sound seems good - would that be OK for track power? My normal power doesn't exceed 14v.

 

[Beddhist]

No Mick, it's an Airwire T5000. I guess you could run it with track power, but you would need a rectifier, as reversing the polarity destroys the receiver. However, if you want track power then why not go for DCC? The Zimo is a DCC decoder.

 

[PhilP]

No Mick, it's an Airwire T5000. I guess you could run it with track power, but you would need a rectifier, as reversing the polarity destroys the receiver. However, if you want track power then why not go for DCC? The Zimo is a DCC decoder.

I guess the reason is he is analogue?? - That, and the 'start-up' cost of going DCC!

Re: sluggish response.. Check the momentum settings in the decoder.. Not sure what CV's they are in the Zimo, but sure the answer will appear here anytime soon! ?Someone?

Well done on a 'first' for you!
See, not too scary is it??

 

[trammayo]

Ah the dark art of DCC! Trouble is, it would cost me a fortune to convert! The sound just seemed right.

 

[trammayo]

Ha Phillip got in before me (I'll have to sharpen my one-finger typing skills - pencil sharpener?). With short arms and deep pockets, I'll never convert

 

[Beddhist]

Thanks Phil. Actually, it was a bit scary. I was worried about the magic smoke, as my history of soldering and electronics is not too hot. On top of that, there are two wires connected to the opposite end of the Zimo which aren't documented anywhere online. In the end I squinted and read the postage sized paper in the box and there they were: for the included capacitor to bridge power outages. Well, I didn't need to wire that one.

The sound file is available to listen to on the Zimo web site, so I guess you could download that and install it in a sound board. It's a free download, so I guess it is OK. Your voltage would be ok, the Zimo is rated at max. 35V DC or DCC.

Re: sluggish response.. Check the momentum settings in the decoder

I don't mean in response to throttle settings. That I can understand and I think it is well done. But issue two commands in a row and the 2nd is ignored. I don't know whether this is the Convrtr or the Zimo, but one of them behaves like an old computer: no commands are accepted until the current one is completed. So, you can't whistle twice, for example. Perhaps it's got something to do with the old rechargeable batteries in the throttle. Unfortunately, I have no access to a DCC system, so I can't compare.

I notice that the top speed is not very high, nor is the sound volume. I suppose I need a higher voltage.

Speaking of voltage: what size resistor will I need to wire all 3 lighting LEDs? I can use just one R, I assume?

Cheers,
Peter.

 

[shropshire lad]

An MX645 needs a minimum of 10 volts to operate. At that voltage you should get full sound volume and with a 3 watt output they can make plenty of noise.
What is the rating on the speaker? For good sound quality a 4 ohm (or two 8 ohm) speaker(s) is a must and completely sealing the enclosure with silicone or blue tack will not only improve the volume but also the quality of your sounds.

 

[Beddhist]

Thanks for that info. I don't know what voltage comes out of the Airwire Convrtr, but I hope it doesn't eat more than 1V. The info on speaker impedance for this one is contradictory, it ranges from 2 and 4 to 8 Ohm. The speaker I'm using is 8 Ohm. The horn sounds quite loud. I will remember your hints when I assemble the truck and I will get a battery with more V.

Cheers,
Peter.

 

[shropshire lad]

Peter
I inadvertantly connected an 8 ohm speaker to one of mine and thought I'd somehow blown the amplifier such was the loss of volume and quality!
As you had an issue identifying the capacitor wires I'm guessing you haven't got a manual, which is available to download at zimo.at. The manual clearly states that a 4ohm speaker/combination is required.
Hope this helps.

 

[Beddhist]

Yes, I have the manual (in German), downloaded from the Zimo web site. In there under tech. specs it says "from 3 Ohm", while under the description it clearly is 4 Ohm, 3W. In the list on their web site it says "4 - 8 Ohm". So you see why I got confused. I can't remember how I convinced myself that it had to be 8. :-\

So, I may have to buy two more speakers.

The two wires for the cap are shown in the manual as connected on the same side as all the others, while in reality they are on the other end and on the underside. The two solder pads are not labelled in the manual.

Now I need to figure out how the sound project uses the F keys.

I just had another idea: I have 2 batteries, so I could put them in series to get 24V to see whether the responsiveness improves.

Thanks very much for your input.

Cheers,
Peter.

 

[itsmcgee]

Peter,
You may find the airwire convrtr does not like the higher voltage. They spec it at a higher 28 volts but when I tried one with 18 volts it would not respond until I lowered the voltage to 14.4 volts. I found that to be very frustrating as it would not allow the decoder to run my smoke feature. May have just been me but let us know what you find.

 

[Beddhist]

Thanks for the warning. I just checked the specs and it says max. is 28V, so putting 2 batts in series should be safe. I will post the results asap. Now I'm curious, said the cat...

 

[itsmcgee]

When I attached the higher voltage battery it didn't destroy anything, thank goodness, just did not work. when I put the lower volt battery back in it worked like a charm for all the normal commands. My particular combination was a Bachmann annie with a Zimo mx695 without sound, phoenix sound and one of the new kadee auto couplers. I installed a switch so I could use track power DCC (which works great) or flip the switch for battery power with the convrtr. Good idea just would not handle the more powerful battery to run my smoke unit properly.

 

[Beddhist]

Interesting, I just made a similar experience: on 24V the motor didn't like running on speed 3 and 4. With the momentum as programmed that makes taking off almost impossible. On the other hand, once I got the speed up it ran a lot faster.

There is always the possibility that my jury-rigged batteries or one of my solder joints doesn't handle the current.

As I lost control one more time and I did an emergency stop using my hand as buffer it spat out the drive shaft. I took the diff apart and found that the pinion gear has a brass bearing, which is very lose in the housing. I shimmed it out with a couple of bits of insulation tape and now it has almost no play. Most of the remaining play is now in the gear box and the excessive motor end float. The universal joints are press fits, so no play at all here, nice and simple.