TCS CN-GP Decoder "Rotary Beacon" Enabling

[robert3985]

Hi Y'all,

I've successfully installed TCS CN-GP (1286) decoders in two of my old Atlas UP GP-30's, and I'm very happy with them, and the installs went flawlessly. 

However, I am in the process of super detailing both engines, and I want a working "rotary beacon" using an orange LED illuminating a clear, amber beacon from underneath.

I've looked over the instruction sheet, which indicates this decoder is a four (yes FOUR) function decoder (information on the TCS site says it is either a three or four function decoder [?]), and also the CV to program to get the "rotary beacon" simulation but nowhere does it say which pad to solder my additional wiring to, or whether I need to use a resistor for this iteration of 1286 decoder.

I suppose I could experiment around and find the answer to my questions, but I thought someone here may have done a similar TCS install before and enabled the "rotary beacon" simulation, and could just tell me the answers to my two questions.

Additionally, the worksheet instructions indicate under "Lighting Control" what they label as "Light Function Wires"...which are White, Yellow, Green and Purple, and the CV number and value of each color of wire.  Unfortunately, only the yellow wire exists on the decoder, and in the Wiring Diagram, the Green and Yellow wires are the only ones which are indicated on the diagram.  There is no Purple or White wires indicated at all.  Hmmm...there IS a "Violet" wire indicated.  Maybe they think Purple and Violet are the same???

Thanks in advance!

[jagged ben]

The pad for the "green wire" function is indicated on this version of the instruction sheet.

http://www.tcsdcc.com/public_html/Customer_Content/Literature/Decoders/N_Scale/Classic_N/CNGPBEMFWEB.pdf

It's at the front left next to the surface mount LED, and the diagram shows an added resistor.

Ignore the colors of the black and yellow wires that connect the two pieces of the decoder together, these are not indicative of functions.

For purposes of the "Lighting Control" interpret the colors as follows (not all of them actually have a 'wire'):
White - front headlight
Yellow - rear headlight
Green - pad, as mentioned
Purple/Violet - ??  Not sure, but hopefully the smaller pad to the right of the front headlight.  And yes, purple and violet must be the same.

[robert3985]

The pad for the "green wire" function is indicated on this version of the instruction sheet.

http://www.tcsdcc.com/public_html/Customer_Content/Literature/Decoders/N_Scale/Classic_N/CNGPBEMFWEB.pdf

It's at the front left next to the surface mount LED, and the diagram shows an added resistor.

Ignore the colors of the black and yellow wires that connect the two pieces of the decoder together, these are not indicative of functions.

For purposes of the "Lighting Control" interpret the colors as follows (not all of them actually have a 'wire'):
White - front headlight
Yellow - rear headlight
Green - pad, as mentioned
Purple/Violet - ??  Not sure, but hopefully the smaller pad to the right of the front headlight.  And yes, purple and violet must be the same.

Thanks jagged ben,

However, I have seen this diagram on the TCS site previously, and the diagram is very different than the one included in the instruction sheet that came with my decoders.

This pdf file says that the CV-GP decoder is a "three function" decoder, whereas my instruction sheet says it's a "four function" decoder.

This file shows only one pad to the left of the front headlight, whereas my instruction sheet and the actual decoder have two pads, one on either side of the front headlight.

This file shows a resistor being used for hooking up an LED, whereas my instruction sheet's diagram does not.

This is the point of my confusion...different specs for the same decoder, and instructions that don't relate to the actual hardware extant on the decoders which are installed and running in my Atlas GP30's (without the "rotary beacon" simulation).

I had the same problem with the TCS instructions as to which wire (orange or gray) was connected to the "top" brush contact for the Atlas GP30 so it'd run "forward" with the default decoder settings.  I figured I had a 50/50 chance of getting it right, and, contrary to the way things normally go, I got it right with the orange wire going to the "top".

I'm figuring the worst I can do is blow an LED as to the resistor question, so maybe I'll hook up an LED where I "think" it should go and give it a try.

[peteski]

Bob, you are too eager to blow things up! 
Seriously, including a resistor in series with the LED will insure that even if there is a resistor on the decoder, nothing will blow up. The LED will just not be as bright.  But if you don't include a series resistor and there isn't one on the decoder then you might not only fry the LED but also the output transistor on the decoder.    That wouldn't be good.

You can always contact TCS (either by email or even call them) and ask for an explanation. They are very helpful and easy to deal with.

[robert3985]

But if you don't include a series resistor and there isn't one on the decoder then you might not only fry the LED but also the output transistor on the decoder.    That wouldn't be good.

You can always contact TCS (either by email or even call them) and ask for an explanation. They are very helpful and easy to deal with.

Peteski,

Good advice!  And thanks for the terminology ("series resistor")...that way, hopefully TCS will know what I'm talking about! 

These three TCS CN series decoders were the first semi-hard decoder installs I've done (two Atlas GP30's and one Atlas GP9).  All of my earlier installs have been essentially drop-ins (with the possible exception of my Digitrax SDN144K0 sound decoders in my Kato E's), and other than several little ambiguities in the instructions, they were easy installs and I'm very happy with them.  I've got about two dozen Atlas GP7/9's to convert, so these installs confirmed TCS's CN-GP decoder's ease of installation (especially on the Geep 7/9's which require no chassis mods).

When I get satisfaction tomorrow morning from TCS, I'll post the answers here for anybody else who may be interested or have similar questions.

[jagged ben]

I would still bet that the function pads are as I described.

Further, it is pretty obvious that there is not a resistor on the decoder.    (The two resistors that are evident are clearly connected to the SMD LEDs that come with the board, and the other two pads are evidently connected directly to the function output transistors.)

[robert3985]

Jagged Ben and Peteski,

I called TCS about an hour ago and talked with one of their service reps.  He was surprised that the PDF file online was different than the printed instruction sheet that goes out with the CN-GP decoder.  Hahaha...he just said that they'll have to update the PDF file.

Just to make sure, he retrieved a CN-GP decoder to eyeball and confirmed that it has two pads on it, one on either side of the SMD front headlight.

He also confirmed that "Violet" is the same as "Purple" in their instructions.

He also said that no resistors are on the CN-GP decoders and that one would need to be connected in series as per Peteski's and Ben's advice.  However, he said that several of their larger decoders have resistors built in, but not the CN-GP because of its small size.

He said that the CN-GP is indeed now a four-function decoder, even if the online PDF file says it's a three-function decoder.

He finished by saying it did not matter what pad I soldered my wires to to achieve the "rotary beacon" effect, either the "green" side or the "Violet-Purple" side.

There ya have it.  The wiring/resistor questions are now solved.

I am sure that some of my questions answers were "obvious" to both of you...that's why I asked.  However, I had problems with TCS's inconsistencies in their instruction sheet vs the online PDF file instructions, and decided to go to the source to both answer my questions and, perhaps, get TCS to clean up their act, which will improve their customer relations.

By the way, the tech rep was very friendly and helpful.  Excellent service!

Now on to installing an LED and seeing if I can figure out how to program the CV's properly!! 

I appreciate the advice from everybody!

[wm3798]

Doesn't surprise me, the design of the CN-GP has gradually evolved over the years.  I'm sure they've moved things around on us.
Lee

[peteski]

Thanks for the follow-up Bob. It is always good to know the solution.