Stupid Proto 2000 decoder problem

[cudaken]

  Simon, you free Monday? I start the new job Wednesday.

[simon1966]

Ken I am actually in town this week, so would be happy to help.  Plus I was going to crimp a new connector onto your DT400

[rrinker]

 Actually what I recommend is this. I think you've had Simon help out with some decoders, maybe he or someone else nearby could help out with this one, but instead of sending the loco off and then getting it back, work together on it so next time you'll be all set to do it yourself.

 Ken's proven he can do some real nice work once he has some experience and instruction - just go back and find some of his earliest posts and compare to where he's at today. It's truly remarkable and something to point out to other newcomers who get frustrated early on.

                                           --Randy

[cacole]

cudaken

Could I just wire a LED to the board with out a resistor?

Sure you could. 

But if you want it to work, you probably need a resistor.  Otherwise it won't light up at all if you get the polarity backwards, or it will just make a bright flash like an old camera flash bulb without the resistor, or the decoder's function output will release it's magic smoke.

With your track record of burned out decoders, lights, motors, etc., you should get someone else to do it for you.

 

[cudaken]

  Thanks for the answers. Could I just wire a LED to the board with out a resistor?

[WSOR 3801]

 I would suggest taking out the flaky P2K board and using a TCS A4X or equivalent board-style decoder.  Bottom one has the replacement.  The replaced one runs better.

The stock P2K bulbs are 1.5 volt.  They still work with a decoder plugged in, newer P2Ks had the problem Randy relates.  The Athearn bulbs might work, or they might pop quickly. 

If you can get the weights out, cleaning up the gearboxes helps quite a bit on these.  the old grease P2K used turns into peanut butter.  

[rrinker]

 Definitely something wrong besides the missing light, the function circuit is not connected to the motor circuit.

 The Athearn RTR bulbs are 1.5V. Proto 2000 ones might be 3V, so that wouldn't work. Regardless - normal plug-in installation of a decoder in the P2K locos that actually have a plug bypasses the on-board diodes which limit voltage to the bulb so either the bulbs need to be changed for 14-16V or they need to be repalced with LEDs or they need resistors to keep from burning out the stock bulbs.

 Edit: Oh never mind, SD7. Yeah those are tricky. If you plug the decoder in the resistors on the board stay in the circuit to limit voltage to the bulbs. Although on the one I did, I tried tracing the circuit board and finally ripped the whole thing out as it ended up with one of the resistors going absolutely no where and the other one apparantly in the blue wire lead runnign both bulbs. Fine if you never ever mess up and always have directional lights, so only one is on at a time. It seemed such a mess to be that it seemed best to just remove the whole thing and change over to LEDs. I think I have pictures of that one, actually.

 

                                    --Randy

 

[cacole]

There's something much more wrong with it than a burned out light bulb -- a runaway is a sign of a short circuit or a flaky decoder, not a burned out bulb. 

[retsignalmtr]

Why would a missing or burnt out bulb cause loss of control?

[cudaken]

  I have a SD 7 PK 2000 and I am using the stock PC board and a Digitrax DH 163. I was going to add LED's and never got around to it. In the mean time I lost one of the lights. Now, if I run the engine in the direction the light is missing it becomes a runaway engine. I have to hit the stop button to stop it.

  I know that the light is needed to complete the circuit but cannot find the light and my LHS does not stock any that looks like it.

  I do have some Athearn's bulbs for a RTR SD 45, would they work? Could I just run a wire from side to side of the board?

  I know, I know hard wire the decoder. But I hate hard wiring!

               Ken