Ok, I did a search first, so I believe this would be new topic-don't flame if repeat but...after trying to fit digitrax DH126 decoders to some Bachmann steamers with smoke and finding brand new decoders unreadable on my DCS50 programming throttle, I made a discovery... This after contacting DTX support (great group of people), my local decoder dealer (Steve Valin of Steve's Depot- stellar guy, gives 110% for his customers), all of us stumped- bad throttle (it reads my older decoders) bad decoders? Here's what I found: the Bachmann smoke generator will electrically block polling of CV data! Pull the smoker out from between the chassis half shells, the decoder is read. Reinsert, reset the throttle, power up- decoder is not read "d nA"! Anyone have an explanation for this? Is it merely resistive shunting that's wiping out the coding pulses or some sort of inductive effect of the wound Nichrome heater coil? To be clear: the smoker is fully operational, and it's installation places it across rail power, ahead of and in parallel with the red/black power feed to the decoder. Just curious if this reported and if a workaround (tuning capacitor if it's an inductor thing) to allow data access and smoke!!
My guess is that the smoke generator is sapping too much power from the DCC signal, especially in the programming mode, which puts less power on the track.
Most of us shun smoke because it's an oil-based product that leaves a sticky film on track which can result in the need more more frequent track cleaning.
Yes, let alone bad for the lungs. I'm not using the smoke, but it never occurred to me to excise the generator during decoder surgery! Lesson learned! I'll talk to my engines about going smoke-free!!
The smoke generator is like having a low value resistor across the rails. Electricity is like water, it takes the path of least resistence. Most or all of the brief pulse sent to the decoder during CV reads ends up going throught he smoke unit and not the decoder, so you get a failed read. The read pulses on the program track are already very low current, compared to the main track power. This is the reason for testing new installs on the dedicated program track, when using systems that have them, before putting the loco on the main track. The program track current is low enough that even if there is a wiring mistake, it shouldn't fry the decoder. The decoder must be wired correctly, at least in reagrds to the track power and motor connections, with no shorts, in order for it to read and write CVs. If it reads and writes properly, you can be reasonably assured that the wires are connected properly. You might have the lights hooked up backwards, or maybe forgot to use a resistor for an LED, but an LED wired backwards just won;t light. Forgetting the resistor will blow the LED and possibly damage the decoder, however. And testing on the program track doesn;t cover things like mayve a tab on the truck making contact with something only on tight curves, or a wire laying against a moving part that works fine now but after running for a few hours, wears through the insulation and then shorts out. But it's still a very good safety net.
--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 don't understand the facination of reading back decoder data, especially from a decoder such as this one which appears to be a relatively simple one.
Not sure about all systems, but the ones I have experience with do the read-back as part of the programming proceedure as a verification.
I found a similar problem with having TCS Stay Alive modules attached to a Loksound decoder. If I attempted to write CV's on the Loksound decoder with the TCS module attached, it would scramble the CV's and render the decoder useless. Fortunately it isn't permanent and a re-write of the CV's corrected it once I disconnected the Stay Alive module.
I solved my problem by attaching a micro slide switch on the bottom of the engine to put the Stay Alive module in or out of the circuit for programming. The same could be done with the smoke unit.
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
Same concept, that brief pulse first goes to trying to charge up the stay-alive and there's nothing left over for the decoder to respond with.
Good idea to put a switch on the smoke unit - the stock ones are going to be designed to operate on DC, not DCC - so they are expected to operate at something less than full throttle. On DCC, it will see even higher voltage than full throttle DC, and it will get way hotter than normal. Even on DC, runnign them dry is not a good idea, so being able to switch it off if you aren't going to use it is a very good idea.
Not meaning to vere off-topic, but will a decoder equipped with a TCS Stay Alive module program properly if it is allowed to attain a full charge first ? My experience was based on new modules that haven't been charged yet.
I know this isn't a problem when using ESU's stay alive module as they have a built-in buffering circuit.
It may be theoretically possible but I'm not sure how you would accomplish that. Even with the lights all off and sounds muted, the decoder will draw some power. Maybe with a drive-on program track, drive it in, all lights off, sound mute, then flip the switch to program and MAYBE it would work, at least a little bit. Stick witht he switch, I think. It even mentions this in the Loksound manual. I do believe that if instead of the simple KA module, you used either Loksound's or the Lenz module (that use 3 wires) it will work fine on the program track, that third wire is a control signal. That's partly why the Lenz module costs more than the TCS, the TCS is just the capacitors with a simple resistor/diode inrush reduction (I think - perhaps they have nothing, but that much capacitance would ordinarly be a huge inrush without some limiter), while the Lenz ESP module also incorporates some additional control. If you notice in the Loksound manual, it shows hookups for both types of keep alives.
Never tried any of the Lenz modules yet, but I know there's no problems programming with the ESU Power Pack installed. The drawback is price - almost double that of the TCS modules.
You can buy a lot of micro slide switches for that price difference !
Yup. I might just go for some micro connectors even, once I have a loco set up, I rarely make further program changes to it. I already use them for lights, in locos where everything mounts to the chassis except eh lights. That way I can fully remove and set aside the shell in a safe place, without having to leave long wires that might get caught in something. In fact, I'm more likely to need to work on the shell than the chassis once it's running - I'll put a loco in service and then go back later and add additional details and do things like paint the handrails.
With all due respect Maxman, it's not a "facination" it's documentation! Do all your DCC steeds operate the same way? From 0-4-0 switchers to GG1's to Doodlebugs? If so and your happy, good for you! For me and many others, readout (and modification) of the default is essential to realistic operation. Hence the big obstacle when the smoker blocks proper input/output in tailoring performance stats. Currently I'm running 50 different steam/diesel/electric/other locos and this was a first for me, hence the post. Digitrax was stumped too!!!
There is now officially no smoking by operators, visitors, or motive power on my layout. Compliance testing may be run at any time!!!