One of my favorite sayings is "Just because you are paranoid doe's not mean they are not out to get you"!
About ready to give the PK 2 SD 7 another try. I have hard wired the decoder and found no shorts between the axles. Getting ready to read the decoder on the test track.
This time to be safe, I was going to hook up my E Z Command to a 3 foot section of flex track and give her a try. E Z Command is only has 1 amp power. Do you folks think it is possible to BBQ a DH 123 decoder with just one Amp?
Thank you for your time.
Cuda Ken
I hate Rust
I believe that the decoder rating is for the motor draw. I have a Digitrax system that puts out 5amps. No fried decoders here. Joe
Ken,
The DH123 is rated for a maximum motor draw of 1.5 amps, but that's not necessarily it's tolerance for current dissipation from various miswirings or short circuits.
So yes, depending on a number of factors such as the nature of the power applied, where it's applied to, what's shorted and for how long, etc. it isn't inconceivable that you could burn out a DH123 with a one-amp DCC system.
For example, back-feeding that one amp of DCC current into the motor outputs would probably do it.
1 amp can definitely BBQ it. Like Steve said, the 1.5 amp ratign is the direct load on the output motor drive, but a short between the output and track input can put power through other parts of the circuit that aren't necessarily capable of handling 1.5 amps, because all they do is control the part that CAN hand the 1.5 amps. And power semiconductors are complex beasts. The current loop to the motor might be designed to handle 1.5 amps, but a different path through the same component might be rated for only say 25ma. Or, current int he forward direction might be 1.5 amps, but in reverse - a fraction of that.
Volts not amps, but a sort of example is a diode. a 1N4001 rectifier diode can handle 50 volts in the wrong direction - like water piling up behind a ***. Above that and the *** breaks - poof, out comes the smoke. An LED though, can only take a couple of volts in the reverse direction - which is why an LED and resistor alone isn't a great idea for AC - it works, but 60 times a second it's getting a reverse voltage that exceeds the rating. A bi-color LED with resistor is ok - because witht he current flow in any given direction, the unlit LED is only seeing the drop across the lit LED as the reverse voltage - 3 volts or less, well within the rating.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
If everything is wired correctly, NO.
On average, many DCC controllers put out 12 to 14 volts to the track, whether they have 1 amp or 8 amp capability. Too high a voltage can burn out the full wave diode bridge. The EZ Command is not a problem.
A loco with a motor and lights that requires 2 amps will blow out the decoder.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
YEP !!!!!
That is why I think you should test it first on the programming track.
If your present DCC system does not have a programming track capability, I would seriously recommend that you trash it and get something better. Like an NCE or Digitrax system.
If you don't have a programming track capability, you are ALWAYS gong to have this problem of trying to test new decoder installs without blowing them.
Elmer.
The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.
(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.
A mis-wired decoder will smoke with very little current. Some have done this. If you are new to DCC, like was suggested, get a system like was recommended. My NCE Power Cab spotted a mis-wired decoder that would have smoked.
Thing is, he DID that - he tested one on a PR3, low current program track. It programmed fine. Set it on the DCC main - poof. So just because it programms and reads back is not 100% guarantee it won;t smoke, although I tend to think such things are isolated incidents and point to a defective decoder in the first place, unless somewhere in the process of moving the loco fromt he program track tot he main, a wire came loose or somethign twisted around to cause a short that hadn't been there.
rrinker Thing is, he DID that - he tested one on a PR3, low current program track. It programmed fine. Set it on the DCC main - poof. So just because it programms and reads back is not 100% guarantee it won;t smoke, although I tend to think such things are isolated incidents and point to a defective decoder in the first place, unless somewhere in the process of moving the loco fromt he program track tot he main, a wire came loose or somethign twisted around to cause a short that hadn't been there. --Randy
Ok, I did not see, He tested on a PR3.
I do know a few have put a loco together and had a short occur.
I don't count the PR3 as part of the original Digitrax DCC system. It is an add on that may not have certain features. One of them being able to push through a mis wired decoder to program it anyway, which is exactly what happened.
If the decoder isn't wired correctly, the PR4 won;t program it any betetr than a DCS50 or DCS100. It;s BETTER than using a DB150 since that uses full power to the program track, and there is no way to read back to verify a change was actually accepted. The PR3 is current limited liek the programing functionality in the DCS command stations - I'm not sure what you mean by it allowign a miswired decoder to program anyway. The PR3 in standalone mode does nothing more than send NMRA DCC program commands to the track with a very limited current. If the decoder can;t acknowledge correctly, due to miswiring, you would get the JMRI equivalent of DnR or DnD errors.