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Bachmann Spectrum circuit board modification???

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  • Member since
    April 2009
  • From: Sweden
  • 1,468 posts
Bachmann Spectrum circuit board modification???
Posted by Graffen on Wednesday, October 28, 2009 5:01 AM

Hi, I wrote in another thread about my problems with my Spectrum 2-8-0.

I want to modify the circuit board for better DCC operation and I would like to know what to modify/cut. There are some capacitors that shouldn´t be there as they can disturb the HF motor control as I understand it. Possibly there are some more components that should be removed?

I compared it with the older 2-8-0´s c-board but it isn´t the slightest resemblance between them!?!

It would be nice to see how to do it as I don´t want to make a mistake on it.

By the way, circuit boards and I are obviously natural enemies as I can´t make my way around this.

Swedish Custom painter and model maker. My Website:

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  • Member since
    January 2009
  • From: Maryland
  • 12,897 posts
Posted by ATLANTIC CENTRAL on Wednesday, October 28, 2009 5:59 AM

Graffon,

If you have one of the newest circuit boards the motor capacitors are the small square PC mount type that look like PC mount resistors. They are located near the motor lead connections and can be easily cut/scraped off the circuit board.

Removing them will improve DC operations as well as preventing interference with some decoders.

BUT, for the very best DCC operation you would be well advised to remove the circuit board all together and hard wire your decoder.

Sheldon

    

  • Member since
    April 2009
  • From: Sweden
  • 1,468 posts
Posted by Graffen on Wednesday, October 28, 2009 7:00 AM

 Thanks for the answer. I looked at it and decided that if I have to change the headlight I could just as well remove the board and hard wire it using a 8 pin socket for ease of service.

Swedish Custom painter and model maker. My Website:

My Railroad

My Youtube:

Graff´s channel

  • Member since
    October 2006
  • From: Western, MA
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Posted by richg1998 on Wednesday, October 28, 2009 9:46 AM

The capacitors should be labeled C! and C2 if two capacitors. Some boards had only one capacitor. For the chip type capacitor I use a small pair of side cutters and clip it off the board. If you have a light bulb in the loco, no other operations are needed. The two inductors are out of the loop without the capacitors.Think tuned circuit.

For LED headlights. Bachmann sometimes uses a series resistor that is around 3,000 ohms which results in a dim headlight. There have been complaints about dim headlights in Bachmann locos. A 1,000 ohm resistor is sufficient for LED's and allows 10ma of current.

If you hard wire the decoder, insert a 1,000 ohm resistor for LED headlight.

I have modified Spectrum locos this way with excellent results.

 Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

  • Member since
    April 2009
  • From: Sweden
  • 1,468 posts
Posted by Graffen on Wednesday, October 28, 2009 11:12 AM

 Thanks a lot! Now I can get on with the project. I spent the time weathering it, so now it is almost ready.

Swedish Custom painter and model maker. My Website:

My Railroad

My Youtube:

Graff´s channel

  • Member since
    October 2006
  • From: Western, MA
  • 8,571 posts
Posted by richg1998 on Wednesday, October 28, 2009 11:45 AM

Forgot to add. All Spectrum tenders are not wired the same. I bought a USRA medium tender. No resistor for the locos that have a LED headlight. Being an electronic tech for many years I always dig out the multimeter and check out the wiring first.

 Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

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