Piko G-Scale BR80: DCC sound module installation

After the successful installation of the DCC decoder on my first G scale locomotive (described here), the time has come to install the sound module and bring some more life to my train. I again bought it from MSL and it set me back a little over 100€ which is quite a sum, so my expectations were rather high.

The PIKO 36193 sound module comes in a box that looks identical to the one the decoder comes in. It's very sturdy so you can be sure your new purchase is safe during transport.

It differs on the inside. The speaker is held securely inside some polystyrene foam. Included you'll also find a documentation describing the installation and the functions of the module in both: English and German.

The module itself is very small. It looks tiny compared to the size of the speaker. You also get some screws and a small piece of a double sided adhesive tape.

Let's move to the installation. We already know how to disassemble the locomotive, so I'll skip those steps. This is what the inside looks like before the sound module is installed.

The basic installation of the set is really trivial. The SUSI connector fits easily into the socket in the decoder and there's a dedicated space for the speaker. No doubt at all about how those should be connected.

And once connected, the first tests are immediately possible.

In the next step you want to attach the module to the chassis, so that it does not move around, This is where the double sided tape comes into play. And I also added some extra insulation tape to hold the wires.

The speaker gets attached using the provided screws. You do have to use some force to screw those in. Or perhaps you just need to use a bigger screwdriver than the one I used. But once it's done you do have a feeling that it really holds.

 

I did have some trouble closing the chassis. Once the speaker is in place, there's not so much space left for the cabling. So I used even more insulating tape to hold some of the wires. Even with that the boiler would not go back in.

And then I noticed that the front light cables were loose when they should have been kept in the dedicated grooves. Once I forced them there, the chassis closed.

Now I only needed to put the engineer back in his seat. He was previously attached using an adhesive tape similar to the one provided with the sound module. But since I did not have any, I used some hot glue instead.

And here it is. My locomotive with a DCC decoder, a sound module and a smoke generator installed. Making its sounds for the first time in my garden!

Some final notes about the sound module:

• the installation is extremely easy assuming you know how to disassemble the locomotive
• there's no DCC configuration needed - once installed it immediately works
• the produced sound is clear and loud
• there aren't that many sound functions in it - it's just motor, whistle, bell, coupling and some extra noises when running
• I don't think the locomotive is fully weather-proof once converted to DCC/sound. Even PIKO makes a point about this in the manual. I definitely won't be running it during a rainy weather.

DCC voltage control

In my previous post I described a simple home-made meter that can be used for a proper measurement of the DCC voltage. There are two reasons why you may need to take that measurement:

• your voltage may be either too high resulting in locos getting hot or not running at all (and possibly dying)
• or your voltage may be too low resulting in locos not running at all or running slowly.

I needed the meter since one of my older N scale locomotives was running hot after conversion to DCC. The loco came in a starter set with a power supply that provided a maximum of 14V. Using my meter I was able to identify that my DCC voltage was almost 18V.

I'm not really sure whether the locomotive was in any kind of danger. But it was getting hot and that worried me. So I decided to solve that potential risk. And how could I lower the DCC voltage on my layout?

The simplest way to lower the voltage is to insert a resistor into the circuit. That however does not work well in our case. The voltage drop on a resistor depends on the electrical current and that changes all the time when running the locomotives. In this case the more locomotives would run, the lower the voltage on the track would become.

We need a constant voltage drop instead. And the solution is in using diodes which do exactly that, independent of the electrical current. The diodes however pass the current in one direction only and therefore we always need to use a pair to ensure the full DCC signal. The circuit diagram looks as follows:

So we basically attach some diodes in series on one of the wires connecting our command station to the layout track. Each diode generates around 0.6-0.7V drop and any number can be used depending on the need. Of course the number has to be the same in both directions.

I've decided to lower the voltage to around 15V and that resulted in 4 diodes in each direction. Using my poor soldering skills I created this device which works perfectly:

What kind of diodes do you need for this? Any rectifier diode will work but you should consider two aspects:

• The diode should be 'fast'. The DCC signal is not really high frequency, so it should not matter that much, but it's your choice and the difference in price is very small, so always go for 'fast' diodes.
• The diode's maximum current must be more than what you plan for your layout. My diodes are rated 6A and that's way more than I'll ever need with my N scale trains.

Of course I know that some modern DCC systems allow us to change the track voltage. Even the Z21 I use can do that. But I'm using my command station for two different scales and it's easy to forget to change the setting when going back from my garden layout to my N scale layout. And that's why I prefer to have a hardware solution which ensures that I don't kill my decoders when I make a stupid mistake.

And here's the reason behind my DCC voltage experiments - the very "hot" locomotive:

DCC voltage measurement

DCC is - to a large extent - a plug'n'play system. You simply assign an address to a locomotive and you're ready to go. And the equipment from different manufacturers is compatible, so usually there's nothing to worry about.

There are however situations when something does not work as expected. In the small N-scale it might a locomotive getting very hot when running at full speed. In the large G-scale it could be a locomotive not running at all in some parts of the garden layout.

That's when you want to know what's happening on your track and the first thing you'll want to investigate is the track voltage. Measuring it properly is not trivial. The DCC signal is an irregular square wave and no popular meter can handle that out of the box.

The best solution would be to use an oscilloscope but those are neither cheap nor portable. This might change soon looking at what is becoming available at JYE Tech. But that's a topic for another post...

There are also solutions dedicated to measuring DCC voltage like the RRampMeter from DCC Specialties. But those are not cheap either, and that's why I decided to build something on my own.

So here it is - my own DCC voltage meter:

OK, I know. It looks like a failed school project but I can assure you: it does work just fine.

So how do you make your own? The detailed instructions can be found here: http://www.wiringfordcc.com/track.htm#a4 but I'll try to summarize them below.

All you need is a very simple electrical circuit that will rectify and filter the square wave. It's really just a few components:

So what you need is:

• The rectifier bridge (the four diodes) - I'm using an integrated circuit here, it's cheap and small.

• A capacitor to filter the rectified signal - any will do as long as it is rated above the voltage you're going to measure. Mine is 35V.
  And you might not want to go too high with the capacity, as the more you use, the stronger switch-on surge you'll cause. 1uF should be enough.

• A DC voltmeter - I'm using a component bought on Ebay for around 2-3 Eur

• Some cabling - my choice is a wire with the "crocodile" clips but it's not the best choice in case you want to have the meter connected permanently to your layout

• A housing - I've used a beautifully transparent Apple mouse box

In my case all those components ended up soldered to a universal PCB and then hot glued to the housing. Works like a charm.

An important thing to remember is that such a meter does not really measure its input voltage. It measures the voltage after the bridge rectifier. You should expect that to be lower by 1.3-1.5V compared to the track voltage.

So what you should do is check what the difference is in your case. This can be done by measuring a DC source and comparing your result to a result coming from another "reference" meter. Then you always need to remember to take that offset into account when performing your measurements on the real track.

Total cost: below 5 Eur.
Satisfaction: immeasurable :)

Piko G-Scale BR80: DCC decoder and smoke generator installation

I knew very, very well that my G scale train would be going DCC rather sooner than later. That's why I've made my reservation for the decoder at MSL already some time ago and waited for it to become available. It cost me less than 67€ which is a pretty good price considering the recent price rise at PIKO.

Let's start with some unboxing. The PIKO 36121 decoder comes in a sturdy box which makes a really good impression.

The box is even sealed at its side. Let's open it.

Quite a lot of stuff inside...

We get:

• The decoder itself with cabling
• Mounting screws
• A comprehensive manual (also in English!)
• Quick wiring guide
• Some extra pages I did not care for :)

In addition to the decoder, I'm going to be installing PIKO 36141 smoke generator and I'm going to use it with the PIKO 36210 smoke oil.

Time to disassemble the locomotive. That's when it gets a little tricky. The manual does not describe the disassembly process. It only shows some general assembly steps (it's one picture really!). My guess is to follow the assembly guide in the backward order.

Looking at the bottom of the BR80 locomotive you can see two kinds of screws:

• small ones - holding the front and rear buffers
• large ones - holding the locomotive body

There are four large ones and I'm starting with them. Once they're removed, the side covers come off.

Looking at the assembly steps, the next thing to remove should be the red part forming the steps to the driver's cabin. But that part just wouldn't really move. I wasn't sure which direction I should be pulling or pushing and was afraid to break it. Finally I discovered that this part can be rotated and then it reveals the next six screws that hold the green cabin.

The screws are gone and the cabin comes off. The next part to remove is the boiler. There are two screws holding it next to where the driver is glued.

Here the screws are no more but the driver's leg would not allow me to remove the boiler. What should I do?

Sorry, Mr. Piko, you will have to step down for now.

The driver was removed and I knew I should be pulling the boiler up. But it just wouldn't move. Looking back at the manual, I've realized there's one more screw holding it. To get to it, I needed to remove the front buffer (two small screws under the locomotive). And yes, the final large screw is really there.

With the last screw gone, the boiler can be removed (almost) easily. I had to be careful, since the driver's seats were still a little in the way.

The insides of the locomotive:

The disassembly was not trivial but it was not very difficult, either. It took me around one hour but I was being really careful doing it for the first time and owning a BR80 with a lot of fragile details. Next time it will be much quicker.

Compared to the body disassembly, the installation of the decoder is really very, very easy. It takes literally five minutes. And that is only because the S1/S2 and M1/M2 symbols are not very well marked near the locomotive's connectors and you have to look carefully to find them.

Of course, I'm attaching the smoke generator, too. You can choose which DCC function it will respond to but it makes perfect sense to follow the wiring diagram and attach it to output #1.

For some reason, the generator won't go all the way into the chimney.

First test. Lights on - check, Lights off - check, Function #1 on - yeeeey, it's smoking!
The test is performed with Z21 command station and the Roco 18V DC power supply. I'm surprised by the significant amount of smoke being produced at only 18V.

The generator still wouldn't go all the way in. I had to use a small file tool and enlarge the the hole in the chimney. Now it looks OK.

I started assembling the locomotive back. One interesting thing I noticed - the driver's seats can be rotated! Perhaps I did not have to remove Mr. Piko at all!

The locomotive is back in its full shape. Well, almost... I know I will be installing the sound module soon, so I skipped some screws and skipped glueing the driver back. It has to wait for the next disassembly.

As mentioned above, I'm using Z21 for DCC control. I did have some trouble programming the locomotive with Z21. Luckily the manual covers that case (mentioning Lenz central station) and recommends programming through a 47 Ohm resistor. I did not have 47 Ohm but two 20 Ohm resistors did just fine. The locomotive has its own address now.

Here's a test video showing the locomotive operating in DCC. This is again Z21 but this time it's powered by 22V DC PIKO power supply. So I assume it's operating under the conditions the were meant by the manufacturer.

I'm surprised by two things:

• Some squeaky noises at a very low speed - have to investigate that...
• Not so much smoke. Seeing the nice effect at 18V I expected A LOT of smoke at 22V but this isn't the case. Another thing to investigate...

My next step is of course the DCC sound module. I'll be writing an article about its installation as soon as it arrives.