Loksound into Athearn Genesis F7 - Lights? how?

Model Railroader General Discussion (Model Railroader)
1

I’m attempting to install 4 Loksound 3.5’s into two sets of Athearn F7 A & B units - one is SP Black Widow, and the other UP. As there’s no 8-pin plug, we are having to hard-wire the decoder, but the lights in the A units are causing problems, especially in the UP F unit, which has two white lights and one red in the nose.

Can anyone tell me what resistors etc you have to place between the various headlights and the decoder, so they won’t fry on DCC 16 volts, please?

Some one out there must have done this before me!

Thanks for any help.

Brian

2

Loksound decoders support both 12 volt and 1.5 volt lights.

David B

3

Thanks for that!! I had no idea, as I had run into the same issue using NCE decoders. How is this controlled?

4

I want to know how to do this too please, David?! So there’s no need for resisitors? How to you “tweak” the decoder to lower the voltage?

Brian

5

I put one in a single headlight F7 not to long ago. I used a Sunny white LED with a 1K 1/4 w resistor. No problem.

6

Brian,

I answered your question on the Yahoo Loksound Forum as well. I recommend not using the “dimming” feature of the Loksound decoder to limit the lamp current as a decoder reset will return the lamp current to maximum, destroying the lamps.

For best results, use a voltage regulator, LM317LZ or a current regulator, IC 334 to control lamp current. These methods give you great light output while maximizing the life of the lamps. Using a resistor works but will not “clamp” the current if the input spikes or varies according track power, i.e., some systems have a nominal value of 12 to 14 volts, others 14 to 16 volts. Also the lamps will not suffer from startup shock as the filament transitions from cold (lower resistance) to warm (operating resistance and higher temperature).

Check the following links:

http://litchfieldstation.com/lobby/install_pix/IC-334CurrentReg.gif

http://www.tonystrains.com/technews/install-lamps-decoders.htm

The first link is a wiring diagram for the current regulator solution. The second link gives many tips on using 1.5 volt bulbs with DCC decoders, complete with wiring diagrams.

I recommend these solutions to all using low voltage lamps with decoders not supplied with built-in low voltage lamp support.

7

Thanks to all, and to Carl for his answer here and elsewhere - all of it is most appreciated, and will be of good use!

Felicitations for the forthcoming festive season from a sunny (if nippy) Plymouth in the UK.

Brian

8

Really? Athearn Genesis F units have not DCC plug? Being premium diesels, I would have thought that was a “for sure” since even the RTR line has a DCC plug.

9

They do, but it’s a 9 pin plug. Loksound uses an 8 pin plug.

10

Um - sorry to disappoint you, guys, but I can assure you that these Athearn Genesis premium units have absolutely NO DCC-ready facility - either 8- or 9-pin (and I may be mistaken, but isn’t “9-pin” what describes an 8-pin decoder with an extra purple wire?).

There is but the basic DC circuit board above the motor. This is why I am seeking advice about hard-wiring and resistors!

Brian

11

Wow what a pain in the you know what. I thought for sure the Genesis units came easy DCC ready…meaning they have a plug. Sorry for my big mistake [:I]

I only have the F-units that came with factory DCC/Sound. The typical Athearn DCC ready unit has a 9-pin connector, like the newer Athearn/Walthers P42.

Very odd that the Genesis line F-Units are so DCC unfriendly. Guess it makes sense with the DCC/Sound units being so unfriendly [(-D]

12

Well thats really odd that the cheaper RTR have DCC plug and play and the more expensive Genesis doen’st. Thats reverse logic!

I do own 10 Genesis Athearns but haven’t cracked them open yet.

13

It’s because Genesis F7 light controller boards are the same boards used in the original release of units; before the idea of installing a DCC socket. In addition the newer units are made with sound and DCC or DC only. They have not replaced the DC version’s light controller board yet.

14

So to make a DC Genesis F unit DCC, there is probably a “drop in” circuit board decoder like those used on many KATO or Stewart loco’s… almost as easy as plug and play but not quite.