OK, I BBQ another decoder!
Engine is my Proto 2000 SD 7, this is the third decoder it has cooked. Other day I tested the motor and free wheeling it was pulling 1 amp and was running real slow, stall was little over 1.5 amps.
Replaced it with another motor. Free wheeling it was pulling .09 amps and stalled at .80 amps. Installed the motor with drive train hooked up, pulled .45 amps and stalled at .85 amps. So I am good to go!
Set it up on my PR 3 and used Decoder Pro to read and write the CV's, went with out a hitch.
Set it on the track, gave it power and Poof, let the smoke out?
Just tested the motor in the chassis again, still pulls .45 amps and stall's at .85 amps. So it is not the motor or drive train.
Engine still has it stock light board, I am going to pull it and hard wire the next decoder.
The SD 7 came DCC ready and ran for 3 years before it became a problem.
If I had a wire grounded, would Decoder Pro still read the CV's?
Is there a safe way to test a engine and if there is a problem that will not let the smoke out?
Thank You folks for the coming answers.
Ken Cooking Decoders Again
I hate Rust
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Well I'm kinda new to this but this is what I have done
"A separate low-current programming track is needed only for first time programming of locomotives with user-installed decoders. The low current to the programming track protects the decoder if the installation was performed incorrectly. To create a programming track, connect a resistor in series with one track wire to an isolated section of track (figure 14). A 100 ohm 10W Wire wound Resistor (Radio Shack Catalog # 271-135) is recommended (figure 14)."
By reading your post though you know your amp draws and stuff so I'm assuming that you already have a programming track. This is what I do and I've never had an issue.
Your obviously way more advanced into DCC than I am but thought I would throw my thoughts out there just in case
Any time after I just instal a new decoder in anything, I put it on my programming track and see if it will read back. I use an NCE Power Pro, and if it doesn't read back or just times out, something is wrong. If it does read back AND will program correctly, then it's good to go. I haven't had any problems with decoder installs since doing things this way. AND - I have found some mistakes and got them corrected before I put the loco on the main by doing things this way.
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.
Elmer and Mike. That is why I used Decoder Pro first. I could write then read the CV's I wrote. Was pretty sure I was home free. Then I got my hat out and started cooking!
Guess I am going to try out Digitrax No Fault Warranty.
Ken
You can build a current limited test track by using a 100ohm 1/2 watt resistor in series with one of the track power wires. That will save your decoders while testing. However, your problem seems to lie in keeping the motor brushes or functions isolated after testing. Normally, if the decoder programs, it is isolated. A short between a motor brush and the rails or a function lead and rails will result in no programming. D The decoder would not be damaged if using a current limited programming track. It just simply will not program.
I would have a good hard look at the installations. Could the motor be torquing up and causing a momentary contact? Maybe some extra space is required between the frame and motor brushes to allow for movement?
Martin Myers
Dunno what all the extra stuff would accomplish - using the PR3 first IS a current-limited program track. Normally you should not be able to get good reads and writes if there is a wire crossed, like a track wire contacting a motor wire, but it's not 100% foolproof.
There is always the possibility that the decoder was just defective, and was able to handle the reduced power of the program track but once full power was applied - poof. That's what warranties are for. They make these by the thousands, and the individual components posibly int he millions (since the circuit chips aren't used just for DCC - otherwise decoders would be a LOT more expensive), so to have one slip through sub-par now and then is somewhat expected. Not to mention the new lead-free standards require the board and components to be subject to a much higher heat level during the manufacturing process - compontnes rated for ROHS are supposed to be able to withstand this increased temp in a non-operational mode (ie, when the board is made) but if there was any attempt to use up any old pre-ROHS inventory of chips, you cna have issues caused by the process as well.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
So I may be right, if Decoder Pro could read the decoder there good chances I did nothing wrong. Makes me feel a little better.
When I put it on the main, I had no lights. I moved it a little thinking the wheels may have been dirty. Motor moved then poof. Last a 10th of a second if that.
Going to pull it apart and double check my install. Hopefully this time I won't the decoder.
Thanks again folks.
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Graffen, I have had outstanding luck with Proto's. In fact the SD 7 has around 200 to 300 hours of run time.
Mine have all been fine. Lots of extended run time at the club on my Geeps - but then, I rip out the factory boards and hard wire almost all of my decoders, and use LEDs.