E 33 Decoder install

[Reinhard S]

Hi.

My apologies in advance if this subject was touched on before.  I have purchased a new Virginian E33 Spectrum electric locomotive #82404 and plan on installing a TCS T1 decoder with a harness connecting said decoder to the 8 pin plug on the board which came with the locomotive.  Do I need to make any adjustments to the board itself?  I believe I read before that a capacitor needs to be cut in order for the decoder to perform properly.  It appears that the board has 3 capacitors.  Which one needs to be cut?

Thank you for your assistance.

All the best.

Reinhard

[richg]

Cut them all. Some have one, somw two, some three. My latest has five.

Rich

[Jim Banner]

If in doubt, cut just one lead of each capacitor and bend the second lead so the pieces of the cut lead do not touch.  Done this way, it is easy to bend the capacitors back into position and solder the cut leads back together.  This tip is most helpful when you cut the lead of something you think is a capacitor but it turns out to be something else.

Jim

[richg]

If in doubt, cut just one lead of each capacitor and bend the second lead so the pieces of the cut lead do not touch.  Done this way, it is easy to bend the capacitors back into position and solder the cut leads back together.  This tip is most helpful when you cut the lead of something you think is a capacitor but it turns out to be something else.

Jim

In addition, more and more, Bachmann is turning to Surface Mount Devices in the PC board setup.
My newest Spectrum has two wire wound inductors that are the only two devices with wire leads.

If in doubt, each device has a label next to it whether a leaded device or SMD.

You have to completely clip off the SMD capacitors. There is no way to clip just one side of a SMD cap.

Some PC boards have two inductors that look like resistors. Some have two wire wound inductors.

D for a diode.
C for a capacitor.
L for an inductor.
R for resistor.

What throws some, the capacitors are soldered right on the motor leads.

Rich

[Reinhard S]

Thanks Rich and Jim for the valuable information.  May I ask why this procedure of cutting the capacitors is necessary?

All the best.

Reinhard

[richg]

Thanks Rich and Jim for the valuable information.  May I ask why this procedure of cutting the capacitors is necessary?

All the best.

Reinhard

The capacitors are actually in place to satisfy a European emissions standard. They aren't needed for normal operation and recommended removed for DCC.
The non sound decoders that come with the Bachmann products work OK with the caps.
Most decoders sold now do not like playing with the caps. Slow speed operation is where many see issues.
If you are not going to replace the on board decoder with a newer more efficient one, then just leave the caps in.
The capacitor/s and two inductors form a tuned circuit. With the caps out, the inductors are not an issue. Some who do not understand electronics remove the complete board.

There are resistors and a couple diodes used for the LED's.
One tender I have uses no resistor for the light bulb headlight and a 22 ohm resistor to dim the light bulb in reverse operation.

Unfortunately, Bachmann has variations between tenders that is poorly documented the last I knew.
A couple people here have posted some of the difference's.
I suspect the stop in tender sales may be because of this issue.

Others will add more info on this issue. Actually well known capacitor issue among many DCC users.

Rich

[Reinhard S]

Many thanks again.

All the best.

Reinhard

[kamerad47]

Pictures helps everbody alot!!!!!!!

[richg]

I was doing that when you posted your message,

PC board from a Spectrum 4-4-0. Top.



Bottom. I suggested removing the inductors for more room and replace with wire jumper.



Older Spectrum 4-6-0, DCC ready.



That will show you leaded caps and SMD caps.

Rich

[richg]

By the way, anyone here can right click on any photo here and save it to your PC for future reference.

You can also highlight the complete message and copy, then paste into a Word Document. The text and photos insert into the document.

Rich

[Reinhard S]

Wow!!  Thanks again Rich.  A picture is worth a thousand words.

All the best.

Reinhard

[richg]

Below is the new 4-6-0 with on board Tsunami.



Rich

[Jim Banner]

For SMT devices, the equivalent to clipping one lead is to touch both ends of the capacitor at the same time using a clean, well tinned soldering iron.  Both ends will unsolder almost instantly, allowing your to lift off the SMT capacitor with a pair of sharp tweezers.  After the capacitor has cooled, you can solder one end of the capacitor back in place but with the other end clear of the board traces.  Or you can just throw them away - I cannot visualize a circumstance where you would reinstall them.

The capacitors are there to short circuit the high frequency components of the arcing of the motor brushes.  That keeps this radio frequency electrical noise from being radiated to nearby radios and TV's where it can interfere with reception.  Thus the term "Radio Frequency Interference" or "RFI."  Unfortunately, DCC decoders power our locomotive motors with pulses that also include high frequencies in their makeup.  Bachmann uses a type of decoder that produces longer pulses but fewer of them to operate the motors.  This minimizes the amount of high high frequency energy in the motor pulses so that the capacitors do not interfere with the decoders.  Other decoders, usually referred to a "silent decoders," use shorter, more frequent pulses to drive the motors.  This minimizes audible motor noise but increases the high frequency content of the pulses.  With these decoders, the capacitors short circuit a larger percentage of the energy that the decoders feed to the motors, often enough to overload the decoders.  Depending on the exact circuitry in the decoders, this overloading can show up in different ways, all of them bad.  When you remove the capacitors, they can no longer overload the decoders and they respond by behaving properly.

Jim

[Reinhard S]

Excellent.  Thanks very much Jim.

All the best.

Reinhard

[kamerad47]

I just looked a my 70 ton (DCC on board) it has 3 caps on the motor 2 on the board, my 44 ton also (DCC on Board) has 4 caps on the board  take them all out ??