N Scale Kato RDC/Digitrax Decoder Problem

[davefoxx]

"Help!"  I've tried all of the obvious (to me) solutions to make my Kato RDC-1 run correctly.  First, let me state that there is nothing wrong with the RDC-1.  It ran fine before I converted from DC to DCC.  It also runs fine on DCC.  The issue is the LED lighting.  Oh, and I already reprogrammed CV33 and CV34 to correct the Digitrax software issue that lit the wrong LEDs for forward and reverse running.

For those of you familiar with the decoder, it has four LEDs (similar to the original Kato DC boards), which are one yellow and one red LED at each end of the RDC.  It's supposed to have the yellow lit on the front/red lit on the rear when going forward and vice versa.

Here's what mine is doing:
Forward direction: yellow lit on the front and red lit on the rear (correct!). 
Reverse direction: all four LEDS are lit (NOOOOOOOO!)

Here's possibly a better description of the problem.  In reverse, F0 will turn the proper "rear" LEDs on/off, but, in forward, F0 does not control the "forward" LEDs.  In other words, the yellow LED on the front and the red LED on the rear never go off (that's the problem!).

Thanks for any help, because at the cost of $35.99 (more than I paid for the RDC-1 when it was on sale), I really would like to get this thing working.

DFF

EDIT: I forgot to add that I reset the decoder (CV8 to 008), and that didn't fix the problem.

[peteski]

I installed one of those a long time ago. I seem to recall it being a bit of a pain.  Of course I don't remember if I had to do anything special to get it to work right.  IIRC, there are only yellow and white wires going to the LED boards, or is the blue wire also attached?

[wcfn100]

I did one too a long time ago.  A "pain" is a the word for it.

I can say that I know it can be made to work correctly.  I do remember the first step on all those decoders was to separate the F0 from the directional headlights (making them independent).  Once that's done, it goes better because things start working the way you thing they should when setting/mapping the CVs.

I wish I had the means to read my decoder but my system won't do that.

Jason

[sizemore]

To be honest sounds like a problem with the decoder or just the light boards. I've installed two and ready to install two more, even switched out the yellow LED's for whites, IIRC only had to change F0.

Is it possible that you have the motor board upside down or reversed?

The S.

[davefoxx]

The S.,

I don't think it's an installation problem, because it's one set of lights on each board that just won't go out, regardless of travel or F0 on/off.  I'm not in front of the RDC right now, but I don't think that the board could even be put in upside down and function at all.

Anyhow, I think it's a decoder problem, but I haven't had to the time to go through the return process to send it back to Digitrax.

If you get the chance, please tell me how and what type of white LEDs you used to replace the god-awful yellow ones.  They're terrible.

Thanks,
DFF

[sizemore]

The S.,

I don't think it's an installation problem, because it's one set of lights on each board that just won't go out, regardless of travel or F0 on/off.  I'm not in front of the RDC right now, but I don't think that the board could even be put in upside down and function at all.

Anyhow, I think it's a decoder problem, but I haven't had to the time to go through the return process to send it back to Digitrax.

If you get the chance, please tell me how and what type of white LEDs you used to replace the god-awful yellow ones.  They're terrible.

Thanks,
DFF

I lean towards problem with the board. I cant remember but I think I had a problem with a board short with the motorboard with the contacts/frame. When you install the next one observe the connections, and capton tape liberally.

I used the Digitrax White LEDs. Using Xuron snips, I just cut the existing LED out, drilled out the remaining anode/cathode in the board with a micro-bit and soldered a new LED in there from the bottom of the board. Just observe the Flag before cutting off the existing LED.



I may just have to go play in the Lab tonight

The S.

[peteski]

The LED is a standard T-1 (3mm) size.  I'm not sure if they still do, but IIRC Miniatronics and Richmond controls both sold warm-white 3mm LEDs.

[davefoxx]

The LED is a standard T-1 (3mm) size.  I'm not sure if they still do, but IIRC Miniatronics and Richmond controls both sold warm-white 3mm LEDs.

Thanks, Pete.  I actually would like to also replace those tiny LEDs they use on Digitrax decoders now, because they don't give off enough light for headlights on certain locomotives.  For instance:



That headlight on #5516 is on, if you can believe it. 

DFF

[peteski]

Thanks, Pete.  I actually would like to also replace those tiny LEDs they use on Digitrax decoders now, because they don't give off enough light for headlights on certain locomotives.  For instance:

The problem might be more than just a dim LED.  It is possible that the LED is not well aligned with the headlight light pipe.

The LED itself can also be replaced (if you can solder small components).  Richmond Controls and N-gineering sell warm-white SMD (Surface Mount Device) LEDs.  Few years back Walmart sold LED lights for miniature Christmas trees which were actually warm-white SMD LEDs. Those could be extracted from the light string and used for headlights.

[sizemore]

Yeah the newer Digitrax the lightpoint is further back because they are using the SMLED vs. a standard T1. So the light gets dispersed before it gets to the light tube/front headlight/number boards. Like Pete stated, you could replace the LED with good hands and soldering rig.

I decided to kick it in the lab and its starting to come back to me. The channels for the motor contacts got capton tape, and I actually used Micro Kristal Klear on all the components closest to the frame core. I'll probably just use capton tape along the walls this time around.

I'll post progress later on this evening, and also show how I hid the wires in underneath the seats.

The S.

[sizemore]

Caption tape on the frame:


Channels cut in the frame:


Decoder installed:


HTH,
The S.