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ChessieFan2

Posted - 2010 May 28 :  08:40:37 AM  Show Profile
So I ran into a strange problem with a factory installed Tsunami decoder. The decoder in question is in an Athearn Genesis FP45. The model number escapes me at the moment however.

I purchased Richmond Controls 0603 Sunny White LEDs to install as ditch lights. Got them installed and routed the wires. I placed a 1k Ohm resistor on the FX5 and FX6 tabs of the decoder, connected the wiring. And. . . Nothing.

Okay, using DecoderPro I noticed you can set what type of bulb is connected to each Function output. Changed FX5 and 6 to be LED. Nothing. Set FX5 and 6 to trigger off F0, just in case. Nothing. . .

Disconnected the resistor and LED and tested it using track power to be sure I didn't blow something up. Works fine using track power.

Disconnected the headlight from the decoder and put the LED leads on there instead. Nothing. . .

What am I missing? It would appear my LED/resistor combination is okay as it works from track power, but no matter the output of the decoder, they won't come on. I did reconnect the headlight to the decoder and it worked. So I didn't blowout any of the functions of the decoder.

I'm really at wits end, so any help or suggestions would be welcome!

Thanks,
Matt
aka ChessieFan2

Country: USA | Posts: 71

Nebrzephyr

Posted - 2010 May 28 :  09:17:50 AM  Show Profile
I believe the Tsunami for the Athearn is hard wired for 1.5V bulbs. So your problem is that it does not supply enough voltages for LEDs.

Bob



Country: | Posts: 1185 Go to Top of Page

Mark R.

Posted - 2010 May 28 :  10:33:53 AM  Show Profile  Visit Mark R.'s Homepage
The Athearn Tsunami has an LED Compensation Mode that will need to be activated in order to use your LEDs. This is accomplished by adding 128 to the sum value you have entered in the lighting configuration option. I would assume your Decoder Pro does this in the bulb / LED selection, but you may want to check the CV value manually just to be sure.


Mark.




Country: Canada | Posts: 2000 Go to Top of Page

ChessieFan2

Posted - 2010 May 28 :  10:57:40 AM  Show Profile
Thanks for the responses. Should I remove the 1k Ohm resistor in addition to this since it sounds like the functions will be underdriving the LEDs. Richmond Control's website indicates the LEDs are 3V, so a resistor shouldn't be needed.

Matt



Country: USA | Posts: 71 Go to Top of Page

Bearcreekwest

Posted - 2010 May 28 :  11:08:58 AM  Show Profile
quote:
Originally posted by ChessieFan2

Thanks for the responses. Should I remove the 1k Ohm resistor in addition to this since it sounds like the functions will be underdriving the LEDs. Richmond Control's website indicates the LEDs are 3V, so a resistor shouldn't be needed.

Matt


Unless you are absolutely positive there is no current limiting resistor built into the path in the Tsunami decoder, removing the resistor you have installed will turn your LED into a single pulse flash and will destroy the LED. LED's have to have some form of current limiting via resistance or as power is applied the LED will burn out, instantly.



Don

PRRT&HS 7555
OERM 2133
SASME

Country: USA | Posts: 1551 Go to Top of Page

ChessieFan2

Posted - 2010 May 28 :  11:11:44 AM  Show Profile
Excellent pointer Don! Glad I didn't attempt that. "Single pulse flash." lol

I have some 330Ohm resistors, I'll try using one of those and see if I can drive the LEDs with the CV adjusted.


Thanks again all!



Country: USA | Posts: 71 Go to Top of Page

Mark R.

Posted - 2010 May 28 :  11:18:19 AM  Show Profile  Visit Mark R.'s Homepage
Even with the LED compensation feature turned on, a 1000 ohm resistor is too high a value to illuminate the LED.

It's been a while since I did this conversion myself, but I seem to recall using a 100 ohm resistor. (?) If you have one on hand, try a standard white LED with a 100 ohm resistor and see what you get. I wouldn't try it with no resistor at all initially. If the LED functions with the 100 ohm resistor, but appears too dim - go for broke and try it with no resistor. It should be fine with wired directly with no resistor, but I prefer to err on the side of caution.


Mark.




Country: Canada | Posts: 2000 Go to Top of Page

k9wrangler

Posted - 2010 May 28 :  1:02:24 PM  Show Profile
Have you corresponded with the mfgr of the decoder? That would eliminate the should, ought to, may and probably answers.

Karl Scribner
H.M.F.W.B.I.C.

Sunfield Twp. Michigan

Just a grumpy old man playing with my toy trains!
Friend of SPIKRE

Country: USA | Posts: 2633 Go to Top of Page

Mark R.

Posted - 2010 May 28 :  1:54:37 PM  Show Profile  Visit Mark R.'s Homepage
The Athearn / Tsunami manuals can be found right on Athearn's site under the DCC section ....

http://www.athearn.com/dcc/


Mark.



Country: Canada | Posts: 2000 Go to Top of Page

ChessieFan2

Posted - 2010 May 28 :  2:18:01 PM  Show Profile
I sent an email to Soundtraxx just to clarify, so hoping to hear back from them. The manuals on the Athearn site didn't appear to talk about voltages for the functions. But that is a good link none the less.

Matt



Country: USA | Posts: 71 Go to Top of Page

Mark R.

Posted - 2010 May 28 :  2:57:21 PM  Show Profile  Visit Mark R.'s Homepage
Simple answer there .... turn the function on and measure the voltage across the blue and function pads ! If it's right around three volts (when configured for LEDs) you should be good to go with little or no resistor.


Mark.



Country: Canada | Posts: 2000 Go to Top of Page

ChessieFan2

Posted - 2010 May 28 :  8:53:42 PM  Show Profile
Hmm, 1.5V across the function pads even when set for LEDs. . . Not encouraging. :-(


Country: USA | Posts: 71 Go to Top of Page

Nebrzephyr

Posted - 2010 May 29 :  12:20:48 PM  Show Profile
quote:
Originally posted by ChessieFan2

Hmm, 1.5V across the function pads even when set for LEDs. . . Not encouraging. :-(

It will be interesting to see the reply you get from Soundtraxx. I know when they came out with the TSU-GN1000 (this is before Athearn publicly announced switching to Tsunami from MRC) I talked to Soundtraxx and they told me the GN1000 function outputs were hardwired for 1.5v. And could not be used for LEDs. If one wanted to use LEDs you should use the AT1000.

I'm guessing the OEM version in Athearn engines is nothing more than a relabeled GN1000.

Bob



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ChessieFan2

Posted - 2010 May 29 :  8:59:30 PM  Show Profile
This is extremely disappointing on many levels. I'm already not a fan of sound as it is and I've stuck with this unit despite it. In hind sight I should have checked that the LEDs worked with the decoder prior to securing them to the frame of the model. Just never would have thought they'd be hardwired for 1.5V. Live and learn and guess I'll end up ordering a new sound decoder to replace this one. Bah!!!!


Country: USA | Posts: 71 Go to Top of Page

Bearcreekwest

Posted - 2010 May 30 :  3:44:13 PM  Show Profile
From Quick Start Guide

Lighting Connections
Each DSD is equipped with four function outputs that are intended to drive
headlight, backup light and special effect lights. Each output is rated for
100mA. Do not exceed this rating! Be sure that the combined current of
all lights as well as the motor stall current measured does not exceed the
decoder rating.
12-16V lamps can be directly wired to the function outputs as shown in
Figure 1. Connect the WHITE wire to one of the Headlight leads. Connect
the other bulb lead to the BLUE wire. Connect the YELLOW wire to one of
the Backup Light leads. Connect the other bulb lead to the BLUE wire.
To connect the Function 5 lamp, connect the BROWN wire to one lead and
connect the other lead to the BLUE wire. To connect the Function 6 lamp,
connect the GREEN wire to one lead and connect the other lead to the BLUE
wire.
Tsunami decoders may also be used with 1.5 Volt bulbs or LEDs, which
require the use of a resistor. See the Installation Guide if you need more
information.

From the installation guide

Using LEDs
Tsunami decoders may be used with LEDs, which also require a resistor to
be wired in series, typically about 680-ohms, 1/4W. Unlike lightbulbs, LEDs
are sensitive to polarity. The minus (-) cathode end of the LED (the shorter of
the two leads) is connected to the function output and the plus (+) anode end
is connected to the decoderís BLUE (function common) wire.
1. To wire the Headlight, connect the cathode end of the LED to the one
lead of the resistor. Wire the other resistor lead to the decoderís WHITE
wire. Wire the anode LED lead to the decoderís BLUE wire.
2. To wire the Backup light, connect the cathode end of the LED to one lead
of the resistor. Wire the other resistor lead to the decoderís YELLOW
wire. Wire the anode LED lead to the decoderís BLUE wire.
If you use Functions 5 and 6 for lighting effects:
3. To wire the Function 5 output, connect the cathode end of the LED to
one lead of the resistor. Wire the other resistor lead to the decoderís


Don

PRRT&HS 7555
OERM 2133
SASME

Country: USA | Posts: 1551 Go to Top of Page

Mark R.

Posted - 2010 May 30 :  8:12:23 PM  Show Profile  Visit Mark R.'s Homepage
The above information isn't from an Athearn factory installed decoder though was it ? They are configured / programmed specifically for the Athearn set-up using 1.5v bulbs. The factory installed boards don't appear to have as many user-adjustable configurations as the replacement boards you purchase separately. (?)


Mark.



Country: Canada | Posts: 2000 Go to Top of Page
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