I have an old Athearn Loco that is fitted with an old Digitrax light board ( So old that the board actually clips onto the top motor clip with full electrical contact ) All the lights worked when the dummy plug was in place but now I am wondering when I put the decoder in will it burn out the lights.
There are four terminals on each end of the board the outer 2 terminals each end are wired to the truck pickups, the 2 centre terminals are conected to the lights and there appear to be some very small diodes across the light terminals and on the under side of the board there is a resistor between the pick up terminals at both ends.
Any help would be appreciated, Thanks.
Kay.Div.
If you were running the locomotive on DC when all the lights worked before removing the dummy plug, did the light intensity increase and decrease as you increased and decreased power/speed? If so, the bulbs are very likely 12v to 16v bulbs and should be fine powered directly through the decoder, but since they will be on constantly at full power, there may be enough heat to melt the shell If the light intensity was constant, then they are likely 1.5v bulbs.
Why did you remove the dummy plug? If it is to convert to DCC, why not ditch the old board and hard wire in your decoder of choice? Be sure to isolate the motor from the frame if not already done. I would switch to 1.5v bulbs (if not already) or, better yet, LED's, both of which would require a resistor (probably 1K ohm) if the decoder does not already have them.
The board has an 8 pin socket on one end and a 9 pin plug hard wired to it on the other end, the dummy plug was in the 9 pin plug when I ran it on DCC using address 00. Does this help ?? So now I want to remove the dummy plug from the 9 pin and plug in a DH163 decoder.
Okay, so the loco has the stock Athearn (not Digitrax) light board.
Yes, you can remove the dummy plug and plug in a Digitrax DH163, or any other decoder with either a 9-pin JST plug like the DH163 has, or one with an 8-pin NMRA medium plug. The lights will work fine using either socket.
Just keep in mind that if you use a decoder with the 8-pin plug, you'll still need to remove the dummy plug from the 9-pin socket.