We've all heard of problems doing certain kinds of programming. Many of us have experienced these firsthand. Sometimes, we get suggestions involving the use of resistors to "fool" the programming logic into letting us do things it doesn't want to do.
First, there's the QSI problem. Some QSI sound decoders can't be programmed. I think this is because they have a big capacitor on board, and when the programming track tries to do its thing, the current "in-rush" to the capacitor looks like a short, so the programming circuitry shuts down. I've heard that a 10-ohm resistor in series with the programming track will sometimes allow this to work. Is there any truth to this?
I have trouble programming the Digitrax SFX0416 sound-only decoder. The programmer is unhappy with it until I put a light bulb on one of the function outputs, because the programmer expects to see something that looks like a motor, and the SFX0416 doesn't do that well. Is there a way to put a resistor across the track (in parallel this time) or maybe across the function outputs to fool the programmer?
Any other suggestions to solve other problems of this type?
It takes an iron man to play with a toy iron horse.
MisterBeasley I have trouble programming the Digitrax SFX0416 sound-only decoder. The programmer is unhappy with it until I put a light bulb on one of the function outputs, because the programmer expects to see something that looks like a motor, and the SFX0416 doesn't do that well. Is there a way to put a resistor across the track (in parallel this time) or maybe across the function outputs to fool the programmer? Any other suggestions to solve other problems of this type?
You're only having problems because you're not following the instructions:
"Note that to be able to readback Sound FX CV’s a combination of function lead loads of at least 60mA at 12volts should be connected to these function leads." (http://www.digitrax.com/ftp/SFX0416.pdf)
This is no different than any other decoder that supports readback. They respond to the programming commands by pulsing an output. The CS sees the increased current draw from that pulse and interprets it as the response.
For example, say you are trying to read back a decoder that has a value of "5" for CV1:
CS: "Is the value of CV1 1? (timeout) CS: "Is the value of CV1 2? (timeout) CS: "Is the value of CV1 3? (timeout) CS: "Is the value of CV1 4? (timeout) CS: "Is the value of CV1 5? Decoder pulses motor/function output CS "sees" the increased current draw from that pulse and recognizes that the value of CV1 is "5"
Steve
Edit: Fixed typos
But I don't wan't to follow the instructions!
I've been able to program and read back the SFX0416 all along, by putting a light bulb on one of the functions. However, that's a nuisance, and I don't want to leave a bulb attached permanently. However, it does explain why I couldn't get this to work by replacing the bulb with a 1K resistor. .06 amps at 12 volts computes to a 200 ohm resistor. If I go smaller, I can put a resistor on the line permanently and simplify the job.
What I was really hoping was to put a resistor across the programming track, not the decoder, so that I wouldn't have to open the shell every time I wanted to tweak the sound or download a new sound package.
Resistor ont he track won't work because the palce the load needs to be to allow the decoder to signal back to the command station is AFTER the track pickups, not before or at them. Usually it's a motor load, but when the decoder doesn't have a motor drive, it has to be somewhere - that somewhere usually is a function output instead. The issue with QSI decoders is completely different from this one.
I noticed the new Soundtraxx Tsunami ad in the latest MR says that they program on any system, no additional hardware required - did they change the decoder so you don't need the PTB anymore? Because when the Tsunami first came out, their answer was simply to tell you to buy the PTB. If they fixed this problem that never should ahve been there, I have a reason to change my attitude about them. ANd if they did alter the circuitry to fix this issue, then hello, QSI, when will you do it too?
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I guess I am lucky to have an old Power cab. I set up the program track first then carefully put the loco on it and read and write every decoder thrown its way. No booster or resistor and caps. Even those pesky Blueline decoders are no problem. When my layout is big enough for a 5 amp system then the Power cab will be a bench tool and spare throttle.
Pete
I pray every day I break even, Cause I can really use the money!
I started with nothing and still have most of it left!
Powercab is a "broadcast programmer" just like the Digitrax Empire Builder. That's why it will program anything - more power. Drawback is everything on the track will be programmed so the layout needs to be shut down while programming.
As far as read back, it's already been stated that the decoder won't "ack" the programmer unless there is a load. Try measuring the resitance of that lightbulb and try a similar value resistor on the function. Can't remember off hand what size resistor I used on my home made decoder tester. 100ohms seems to ring a bell.
Martin Myers
MisterBeasley We've all heard of problems doing certain kinds of programming. Many of us have experienced these firsthand. Sometimes, we get suggestions involving the use of resistors to "fool" the programming logic into letting us do things it doesn't want to do. First, there's the QSI problem. Some QSI sound decoders can't be programmed. I think this is because they have a big capacitor on board, and when the programming track tries to do its thing, the current "in-rush" to the capacitor looks like a short, so the programming circuitry shuts down. I've heard that a 10-ohm resistor in series with the programming track will sometimes allow this to work. Is there any truth to this? I have trouble programming the Digitrax SFX0416 sound-only decoder. The programmer is unhappy with it until I put a light bulb on one of the function outputs, because the programmer expects to see something that looks like a motor, and the SFX0416 doesn't do that well. Is there a way to put a resistor across the track (in parallel this time) or maybe across the function outputs to fool the programmer? Any other suggestions to solve other problems of this type?
For the SFX0416 just add a 220 ohm resistor across the Blue/White leads (if you aren't using it for light outputs, otherwise this is not necessary) and it will program fine. It needs a small load. The SFX064D is the same way.
This is from the decoder manual:
Connect the function leads that are to be used from the 9pin Track and Function harness. Note that to be able to readback Sound FX CV’s a combination of function lead loads of at least 60mA at 12volts should be connected to these function leads. Ins.ulate the unused function leads so they cannot short to the locomotive frame or track power
For the QSI decoders, I've never had an issue. The series 7 decoders need to be programmed in direct mode, not page mode, on my Super Chief system.
Engineer Jeff NS Nut Visit my layout at: http://www.thebinks.com/trains/
rrinker I noticed the new Soundtraxx Tsunami ad in the latest MR says that they program on any system, no additional hardware required - did they change the decoder so you don't need the PTB anymore?
I guess they did. I've got a new diesel Tsunami, and it programmed just fine on the programming track with my Lenz.
For reference, the SoundBug will program all by itself, with no additional loads or resistors.
If I had to guess, the Soundbug has a resistor on the board. Not much choice, it has no motor outputs nor does it have any function outputs. I'm so tempted to cut the shrink wrap on mine, because I'm curious about several things.
According to the Soundbug manual it has the same problem but since it is often plugged into a 165 decoder, the problem is solved. Try one in stand-alone mode. The manual says:
The sound project loaded into this decoder may be operated independently of any other DCC motor or function decoder. If another non-Sound FX compatible DCC decoder is connected to the track leads then CV readback of SFX004 Sound CV’s and PR2 SoundTest modes may not be possible. Note that it is always possible to Write CV values using Operations mode or a Service Mode programming track, even if CV Read is inoperative.
If the connected function loads are insufficient for CV readback with a PR2 or an incompatible DCC decoder is also connected, it is still possible to download a complete sound project by using the large green “program project” icon. in the SoundLoader program.
MisterBeasley Snip Any other suggestions to solve other problems of this type?
Snip
My zephyr came with a resistor in the box
but i bought a power paxx booster and never looked back
i can program anything now with no problems
TerryinTexas
See my Web Site Here
http://conewriversubdivision.yolasite.com/
C&O Fan MisterBeasley Snip Any other suggestions to solve other problems of this type? My zephyr came with a resistor in the box but i bought a power paxx booster and never looked back i can program anything now with no problems
The resistor should have been for your LT1 testor, not for the programming track Here's the link for the LT1 instructions.