Model Railroading > Wiring headlight and strobe

I'm trying to wire an LED headlight on a Tsunami board replacement decoder (AT1000 I believe - came pre-installed).  The unit already has a bulb wired into the F6 and 5U ports for the strobe flasher.  In order to avoid the use of a resistor for the headlight LED, my understanding is that I can make use of the third port along the side, F5, for one leg of the LED.  However, when I do so, the headlight flashes in sequence with the strobe.

Is there a way to use F5 for a headlight but have it controlled by F0?  If so, any idea what I've done wrong in my configuration to cause it to flash?

Also, for a simple strobe flasher (NOT a rotary beacon), is it necessary to use both F6 and 5U, or is there a simpler way to wire that that would allow it to continue to be controlled by F6?

As is probably clear by now, electronics are one of my weakest points in the hobby, so I'd appreciate any guidance geared toward about the third grade level. :-)

Joe Atkinson
Council Bluffs, IA
www.iaisrailfans.org/../Sub4WestEnd



Edited 1 time(s). Last edit at 06/29/15 10:25 by iaisfan.

You could remap F0F to F5 but why not leave the headlight where it is assigned? Then use F5 for your flashing light. Then you can program F5 to operate and flash in conjunction with the headlight or independently of it.

Posted from Windows Phone OS 7

The TSU AT-1000 decoder is set up for 12 volt lights with a 1.5 volt option. The headlights F0F and F0R use the end terminals. Then F5 and F6 12v lights use those tabs and the #9 blue wire connection for their positive. If you want all 1.5 v bulbs you can use the two negative connections on the ends for headlights with the 1.5 + for the supply. F5 & F6 also use the 1.5 + for the supply. These connections are all shown in the instruction diagram.

There is no power source for 3.3 v for led lighting on this board. To use leds you will need to use the 12 v connections with 1k ohm resistors in series with each led.

The KT-1000 comes from the factory set up for led lighting. I think the BW-1000 and IM-1000 may also be set for leds since that is what the models from Bowser and Intermountain use in their models.

So your choices for leds are to use the decoder you have and add resistors or purchase a different decoder set up at the factory for leds. If you keep the AT-1000 you have it is probably a good idea to restore the defaults and start the programming from scratch unless you can talk to the previous owner and can talk to him about what he changed in the CVs. Otherwise, there is no way of knowing what was done to try to make leds work on a decoder which was not designed for 3.3v lights.


Posted from Windows Phone OS 7



Edited 2 time(s). Last edit at 06/29/15 12:41 by fbe.

fbe Wrote:
> You could remap F0F to F5 but why not leave the headlight where it is assigned? Then use F5 for your flashing light. Then you can program F5 to operate and flash in conjunction with the headlight or independently of it. 
> The TSU AT-1000 decoder is set up for 12 volt
> lights with a 1.5 volt option. The headlights F0F
> and F0R use the end terminals. Then F5 and F6 12v
> lights use those tabs and the #9 blue wire
> connection for their positive. If you want all 1.5
> v bulbs you can use the two negative connections
> on the ends for headlights with the 1.5 + for the
> supply. F5 & F6 also use the 1.5 + for the supply.
> These connections are all shown in the instruction
> diagram.
>
> There is no power source for 3.3 v for led
> lighting on this board. To use leds you will need
> to use the 12 v connections with 1k ohm resistors
> in series with each led.
>
> The KT-1000 comes from the factory set up for led
> lighting. I think the BW-1000 and IM-1000 may also
> be set for leds since that is what the models from
> Bowser and Intermountain use in their models.
>
> So your choices for leds are to use the decoder
> you have and add resistors or purchase a different
> decoder set up at the factory for leds. If you
> keep the AT-1000 you have it is probably a good
> idea to restore the defaults and start the
> programming from scratch unless you can talk to
> the previous owner and can talk to him about what
> he changed in the CVs. Otherwise, there is no way
> of knowing what was done to try to make leds work
> on a decoder which was not designed for 3.3v
> lights.

Thanks very much FBE.  That was very helpful.

To give some context to the questions, there's kind of a long story behind this.  I bought the unit (Atlas IAIS C420 850) from a friend with the Tsunami, flasher, and LEDs already installed.  The front headlight started flickering after about 15-20 minutes of operation - not like there was dirty track, but more like a constant strobe effect.  Sound never cut out, the motor never hesitated, and other units iin the consist were fine, so I'm confident that it's not a track issue.  It would start this flashing from the moment I turned the headlight on, sitting still, with the same intensity.

In attempting to troubleshoot it, I tried moving the front LED and resistor to the rear.  Same strobing problem there, so I'm fairly confident it's not the decoder.  I said earlier that I didn't have another LED/resistor available, which turned out to be inaccurate.  The rear headlight black lead was wired to F5, with the red lead on the rear headlight pad.  The heat shrink tubing was so thin that I didn't think there were resistors in it, and I thought I remembered reading that F5 and F6 had configurable voltage outputs that could bypass the use of resistors, so I assumed it didn't have them, leading to my earlier question about continuing to use F5 under the thought that I could do so without adding resistors.  After reading your comments, and hearing from the original owner that he only wired to F5 in order to make the rear headlight independently-controlled and that he was fairly sure he added resistors front and rear, I realized that that rear light HAD to already have resistors on it.  So, I simply moved it to the front, where it works fine.  I run fixed consists, so the rear headlights are unnecessary on all units anyway.  Problem solved - kind of.  

I'm still concerned about what might have caused the original front LED/resistor to apparently fail and go into "strobe mode", but I'll start a new thread for that topic.  Thank you again for your great explanation.

Joe Atkinson
Council Bluffs, IA
www.iaisrailfans.org/../Sub4WestEnd

Joe,

I am glad I could help you work with the Tsunami. While there is an led configuration value you can use for led lights rather than incandescent bulbs I don't believe it changes the supply voltage to the function output. An led is digital and goes off to on abruptly while a bulb with a filament is analog and builds to full brightness as the filament heats up. It is much the same when going to off. The led is abrupt while the filament bulb decays to off. Adding a value, commonly 128 to the lighting function output using an led causes the power to apply in a different manner to mimic an incandescent bulb. At last that is the way I understand it. I might be wrong, though.

I had not heard of using F5 or other function for the rear headlight but it is certainly more protypically accurate to do things that way. I am working on an NW-2 switcher and that connection would allow me to have the light against the cars always off while the light on the outside end always dim.

Posted from Windows Phone OS 7

fbe Wrote:
> I had not heard of using F5 or other function for the rear headlight but it is certainly more protypically accurate to do things that way. I am
> working on an NW-2 switcher and that connection would allow me to have the light against the cars always off while the light on the outside end
> always dim.

I have all my consists configured to use F0 for the west-facing headlight and F1 for the east-facer, and when enabled, they're constant on regardless of direction.  It required me to move the bell to F5, but seemed to be easier to remember since F0 and F1 are on opposite "ends" of the keypad.  I really like what this arrangement does for realism.  I've never been a fan of headlights toggling with direction changes.

Joe Atkinson
Council Bluffs, IA
www.iaisrailfans.org/../Sub4WestEnd