Hi all,
Just wanted to share, that last week we had two incidents of Bachmann decoder malfunction, which caused the PWB to burn and char my carpet. Fortunately, me and my wife were at the layout both times and didn't leave the room to pour some coffee or use the bathroom.
The first event was caused by sloppy winding and packaging of one of the solenoid coils, causing opposing ends of the coil to press against one another in perpendicular direction. Eventually, the thin coating on the wire gave in to pressure of the tight enclosure, and boom. The 50 mA output circuit had to handle 0.8 Amp, which it obviously couldn't.
We were lucky to catch both events in the making, however, we don't want to face the future when its not safe to turn your head away from the running layout. And my wife said, no more Bachmann in our house. I already opened and tidied up all the coils and I'm facing pending work of replacing all 8 Bachmann decoders.
Just wanted people to know about our experience. If anyone wants to know more detail, I can provide. Just reply to this message. Best regards,
Andrew

Bachmann site; Amazon; Walthers.

Andrew

Hi Segsig, if you bought a DCC controller, the power supply usually comes as part of the controller set. It is usually a AC to DC adapter with 12.5 - 13.5 VDC output of a certain amperage capacity (e.g. 1 Amp; 3 Amp). Some controllers use AC as input. The DCC controller may state in the manual what kind of power supply is compatible. If you know the voltage and the type, AC or DC, and the required amperage you can get any commercially available power supply that fits the requirements.

If you have any further questions, post a response, I can help clarify further.
Enjoy,
Andrew

Hi Grumpy, these days the LEDs are made using different technologies and they come with different luminosity/brightness. I use LED's a lot -  on the locos, in cars, on the layout for special decoration and effects. I prefer to test them before deciding what drop resistor to use.

For example, if its very bright, you may need to put only 5 mA or even 1 mA current through it. If its not bright, 10 mA will work for most cases, or 20 mA for street lights.

First, you need to know the forward voltage drop on your LED. Usually it is posted on the specs when you buy it, or it can be measured by some DMM in diode measuring mode.
Lets, say the LED forward voltage drop is 2 V. And your electrical source is 12 VDC. The way how drop resistor value is calculated: 12 V (source) - 2 V (LED) = 10 volts, this is LED drop voltage.
If you need to put 5 mA through your LED, the resistor value is: 10 V / 5 mA = 2 kOhms.
If you need 10 mA, the resistor should be: 10 V / 10 mA = 1 kOhms.

If you want to connect two LEDs in series, your LED drop will be 12 V - 4 V (2xLED) = 8 Volts.
For 10 mA LED current, the drop resistor value is: 8 V / 10 mA = 820 Ohms.

Enjoy!
Andrew

Hi all, I'm using bachmann DCC #6 crossovers with powered frogs. I'm also using electrical pickup trucks to add lighting effects to the rolling stock. Everything works all right until a mistake happens in operating the crossovers when the trains are running over. I understand that this causes various types of shorts, but this isn't the problem.

The problem is that the crossover decoders are vulnerable to the electrical transition currents and can get stuck in a certain position, and won't respond to throw/close signals. I did some troubleshooting and ruled out loco decoders; types of electrical pickup trucks and the DCC system. I suspect that the problem is that the decoder memory gets altered and it looses the address that was programmed into it. It is easily fixable by taking the crossover out, reprogramming the address and putting it back. However, its a hassle.

Has anyone come across this defect? Any recommendations how to improve the decoder protection from such spikes and transition currents? Thanks...
Andrew
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Update of Apr 27.
Upon further research it was discovered that Bachmann uses in their decoder a cheap knock-off of the venerable 12F629 controller, and they didn't implement the manufacturer recommended noise protection circuitry. Nothing can be improved here, except unpowering the frogs (not a guaranteed fix) or replacing the decoder with a different brand.
I think I'll go with the latter.
Andrew