Electronics and DCC

I recently installed a Tsunami Diesel decoder in an Athearn Genesis F-2. In the process of soldering the wires to the pick up tabs on the decoder, I soldered a Mintronics 3mm LED in place for the headlight complete with the resister. I used the middle 2 tabs on the front of the decoder that are used for normal lighting, but the LED with resister would not work.

Do these new Tsunami deisel decoders come with a special place to solder LED's? or do I need to change some CV's?

Mike

 Since you mentioned soldering wires to tabs, I assume you installed the Tsunami TSU-AT1000. That version already has resistors on board for 1.5V bulbs, although at what current limit it does not say. There appear to be additional places to attach the lights, bypassing the internal limiter, but for whatever reason they do not have an AT1000 specific manual on their web site. Hopefully the decoder came with some instructions that reference this. Best bet is to enable such a bypass and use your own resistors.

 LEDs are also polarity sensitive, but so long as there is a proper resistor, they won't be damaged if connected backwards - they just won't work. However, at this point, I don't think this is your problem. It's the on-board resistor plus your external resistor.

                                        --Randy

Yes, I hard wired the TSU-AT1000 EMD 567 into my Athearn F-2. Everything works wonderfully except for the LED headlight. As I said, I soldered the 680 resister inline with the LED and soldered the LED to the middle 2 tabs on the locomotive front side of the decoder (once installed) and nothing...no lights. I then reversed the 2 leads of the LED and again...nothing.

Do I need to remove the resister?

 F2?  Athearn doesnt make an F2.

Can you test to see if the LED isnt dead?  Can you also use a Multi Meter to see if your function tabs are working?

If the LED works and the tabs dont, then consider using the reverse light tabs and remap it.

David B

I think you have to hit f-0 when you fire it up ,and there is a map of wireing differant lighting types on the packageing ,1.5 athern an such is differant than say altas . hope youget it going wish I new more ...J.W.

davidmbedard:

 F2?  Athearn doesnt make an F2.

Can you test to see if the LED isnt dead?  Can you also use a Multi Meter to see if your function tabs are working?

If the LED works and the tabs dont, then consider using the reverse light tabs and remap it.

David B

 They actually have several; the ACL unit is linked below:

http://www.athearn.com/Products/Default.aspx?ProdID=ATHG22200

Meyblc:

Yes, I hard wired the TSU-AT1000 EMD 567 into my Athearn F-2. Everything works wonderfully except for the LED headlight. As I said, I soldered the 680 resister inline with the LED and soldered the LED to the middle 2 tabs on the locomotive front side of the decoder (once installed) and nothing...no lights. I then reversed the 2 leads of the LED and again...nothing.

Do I need to remove the resister?

This decoder is setup for 1.5 volt lamps; it appears to have a voltage regulator circuit that supplies 1.5v max on the COMMON terminals. You need at least 3 volts of potential for LED operation. You can use the 1/2 wave supply method by connecting the cathode of the LED to the function lead (F0 Front or Rear) and connect the anode to the LEFT or RIGHT rail through a 1K 1/4 w ( better than 680 in this case) resistor. The higher value is safer for reverse current since you are going directly to the rail power in this case.

 Huh....I stand corrected.  Nice looking F2s...

David B

This decoder is setup for 1.5 volt lamps; it appears to have a voltage regulator circuit that supplies 1.5v max on the COMMON terminals. You need at least 3 volts of potential for LED operation. You can use the 1/2 wave supply method by connecting the cathode of the LED to the function lead (F0 Front or Rear) and connect the anode to the LEFT or RIGHT rail through a 1K 1/4 w ( better than 680 in this case) resistor. The higher value is safer for reverse current since you are going directly to the rail power in this case.

Nope, the AT version has the 14v common on the ends and the 1.5v common on the side of the decoder.

The OP was setting up the LED correctly.  The board needs to be checked with a MM as well as the LED tested.

David B

I'll check the outputs of the decoder with a multi-meter and see what I've got going on. Yes, I'm pretty sure the locomotive is an Athearn Genesis F-2. At least that is what the box says.

The 1.5 volt terminals are "Only" for “1.5 volt light bulbs", not LED's. Some people confuse light bulbs with LED's.

Rich

davidmbedard:

This decoder is setup for 1.5 volt lamps; it appears to have a voltage regulator circuit that supplies 1.5v max on the COMMON terminals. You need at least 3 volts of potential for LED operation. You can use the 1/2 wave supply method by connecting the cathode of the LED to the function lead (F0 Front or Rear) and connect the anode to the LEFT or RIGHT rail through a 1K 1/4 w ( better than 680 in this case) resistor. The higher value is safer for reverse current since you are going directly to the rail power in this case.

 

Nope, the AT version has the 14v common on the ends and the 1.5v common on the side of the decoder.

The OP was setting up the LED correctly.  The board needs to be checked with a MM as well as the LED tested.

David B

Thanks for the correction and heads-up!

Ok.....I checked the decoder with a MM and I found that it is putting out exactly 1.5 volts of power when F0 is pushed, 0.0 volts when F0 is turned off.

I checked the LED wired up to an old Atlas DC powerpack With the same multi-meter, the LED works great at exactly 3.0 volts of DC power.

So.....how do I get enough power (3 volts) to the LED when only 1.5 volts is supplied from the lighting outputs of the decoder?

Any help would be greatly appreciated

Mike 

 Reverse the connections to the LED.  They are polarity sensitive and if you have the positive terminal connected to negative and vice versa, they won't light.

If this doesn't solve the problem, then the LED is bad.

 How big a resistor are you using? 2.7 volts is BARELY enough for a white LED (most need 3.1 - 3.5 volts). 2.7 votls is a rather odd number, if the decoder is set to drive 1.5 volt bulbs, 2.7 no load is probably too high. If the decoder is SUPPOSED to put full voltage to those function leads then it shoudl be around 12 volts.

                                                --Randy