Hello...
I finally got around to installing a Digitrax TF4 into my C&NW bi-level cab car. My plan was to use three of the four functions for headlight, marker lamps, and the roof top beacon using a 1.5v. microlamp.
I have the red and black wires of the tf4 soldered to the bronze strips below the floor. The white to the existing headlight LED, green to the marker lamp LED and the yellow wire to the 1.5v lamp installed in the drilled out yellow beacon. I put 1k resistors on the LEDs and a 680 on the 1.5v lamp. I isolated the LEDs that were mounted to the original pc board.
When I try to change the address using Decoderpro I get a "no response from locomotive" error. The LEDs blink when the program is trying to write but the address change does not take. Using the DT400 I can't seem to get any programming response either.
After I do a "factory reset" in decoder pro I can access the TF4 on address 03 and I can turn on and off all three functions.
Am I missing something in the programming process here? Everything works on address 03 but I'd like to change the address and remap the function outputs to f0 headlight, f1 strobe and f3 marker lamps.
Thanks... Ed
There's probably not enough load caused by the low power of the LEDs. You cna try the 1K resistor trick - put a 1K resistor across the program track to increase the load. Or try Ops Mode and program it on the main. You'll likely have to do the address manually - use a calculator for CV17 and 18 if the address is to be greater than 127, and program both thoses CVs, then set CV29. You can do Ops Mode in DecoderPro to set the light functions.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Thanks, Randy
I will try a little resistance across the programming track later tonight. Never gave the load value any thought. I do use a PTB100 and have never had any programming errors in the past.
Digitrax says in their documentation that the TF4 does not use Ops mode programming. I'll let you know after I mess with it tonight.
Thanks again...
Difference being the PTB100 makes up for decoders that need EXTRA power to program. The TF4 does not - it simply needs enough of a load on one of the function outputs to generate the acknowledge signal. Depending on the resistor used, the load imposed by the LED could be less than 10ma. You might have to swap in a bulb. And bypass the PTB100, definitely not needed here.
YES!
Thank you Randy.
I did not remove the PTB from the programming track but I did use your suggestion and put a 120 ohm 2w resistor across the programming rails. Kind of heavy, I know, but its the one that came with the SEB so I thought I'd try that. I got the TF4 to see the new address then proceeded to assign the functions
The selection boxes in Decoderpro turned red and the error message still showed but I could see it step through each pane of the writing process. I have the strobe, markers and headlight working on function 3,4 & 5 since the selection of output assignments is limited and I can't use the momentary f2.
The lighting effects aren't as sophisticated as in the newer FX decoders but good enough for a blinking strobe.
Thanks again!
With the PTB the 120 ohm resistor probably was ok - without it I'm pretty sure that would be way too low a value and cause excessive current draw - hence it workign with the PTB in place.
As an alternative, unless you actually are using Transponding, TCS has the FL2 and FL4 function only decoders. TCS decoders in general do a much better job of supporting LEDs for fancy light functions as compared to Digitrax. TCS has a wide range of adjustment for the 'dim level' so you can adjust it for bulbs or LEDs. I don;t have any flashing beacons or ditch lights, but I do make use of the adjustment t set the brightness of a Rule 17 dimmed headlight.