P2K 2-8-4 DCC problems

I am writing this for some newsgroup-challenged friends.
One bought a Berk at his local hobbyshop. Tested it in the shop on DC, ran
great. Took it home, put a decoder (Lenz LE1035) in it, fan like a crock -
as if it had a severe bind. Tried it back on DC - smooth as silk. Replaced
the Lenz decoder with a TCS decoder - bind returned. Ditto with an NCE
decoder. DC again - fine. Took it back to the shop and experienced the same
problem with a replacement. Took that back and decided to go without.
At another friends place, tried out his new Berkshire (different loco from
different shop, I hasten to add. Not one of No 1 friends exchanges.).
Installed Lenz LE1035, cut blue wire and wired in 380 ohm resistor to
overcome normal P2K lights problem - this is what we normally do for P2K
steam locos, rather than replace bulbs. Has always worked. Put the tender,
decoder installed but not connected to the loco, no problem. Backup light a
little weak but not objectionably so. Connected loco to tender - bzzzzt.
Short circuit. Disconnected loco from tender. No short. Remove decoder from
tender, restored to DC configuration.
Put the loco back on a bit of totally dead track, and applied 9v DC. Ran
fine. Put loco on DCC track (undecoded), dialled 00 and ran fine. Tried
other decoders (anther LE1035 and an LE 1025) with same result - bzzzt. Loco
goes great on DC, but a complete disaster on DC.
Now over the years our group has installed 100's of decoders. We are not
neophytes at this game. Each install was checked, decoders isolated from
frames, etc, etc. It appears that the problem is in the way the PCB in the
tender is wired when DCC is used. If not, the only other thing I can think
of is our using dropping resistors in the light circuits, rather than
replacing the bulbs with 12v/50ma bulbs. But there has never been a problem
in the 2-8-8-2, 0-8-0 or 0-6-0.
So, anybody had any problems? Got any suggestions? HELP!!!
Steve
Newcastle NSW Oz
Reply to
Steve Magee
Loading thread data ...
"Steve Magee" wrote
just one right now (I do not have that model!): is there any RMF suppression circuitry, like a capacitor across the motor leads? If so, check if disconnecting them solves that problem
another question: is the motor by chance one of those iron-less types? These do not like pulse-power
/jw
Reply to
Jens Wulf
These do not like pulse-power< Not in plastic engines, the cost would be to high. Pulse-power could be the problem however except for the fact the LE1035 is a silent running decoder. Also the TCS decoders are quiet running and so are the new NCE decoders. Often this problem is a capacitor installed for RF radiation problems. Usually cutting this capacitor out will fix the problem.
Reply to
Jon Miller
This is normally what we do for Bachmann loco's - removing chokes and capacitors, have never had to do it with P2K. I shall check, but I don't recall seeing a cap on the PC board.
Thanks for help, guys. Shall see if there is a cap and what happens if we reconfigure the board. But feel free to offer any other suggestions!
Steve Newcastle Oz
Reply to
Steve Magee
Steve, I'm an N scaler so I don't usually have a luxury of plug-n-play decoders, but maybe I can offer some hints.
Since you are a seasoned installer, you could try tracing the motor connections right from the motor, all the way to the DCC plug. The traces on the circiit board should be visible, so you can see if they go anywhere else besides the DCC plug and the motor.
Another option would be to unsolder the existing wires from the motor then hook up temporary jumpers to the motor. Take those wires and hook them up directly to the motor outputs on the decoder (orange and gray). Then hook up the red and black leads from the decoder to the the DCC plug (or directly to the rail pickups) using 2 more temporary jumper wires. Now you have the motor fully isolated from the circuit board. So, you only have 4 connections to the decoder and the loco should run well. If it doesn't, then there is something "funky" with the motor itself ( this is highly unlikely). If it runs Ok, then as you said, there is fomething "fishy" on the circuit board between the motor and decoder. As I said, you should be able to visually follow the traces and see where they go.
BTW, "funky" and "fishy" are highly technical terms.
HTH ! Peteski
Reply to
Peter W.
Thanks for your observations, Pete. Current thoughts are leaning to an unwanted connection between pins 3 and 7 in the socket - not the plug - in the tender. We will look at this first, then move on. After all, the loco is brand new, so the "return it to the shop" option still very much exists. Shall see if the owner wants to strip the loco further before getting into real trouble shooting.
Your technical terminology is noted. Rates right up there with "tads", "smidgins" and redefined versions of base (and I do mean base) Anglo-Saxon, that often accompany decoder installations here... :)
Steve
Reply to
Steve Magee
The even more important question is - where is mine? Did my wife snag it from UPS to put under the tree? Gene ABV61-1043.001.HCB
formatting link
"Skinny Dipping and Other Stories" On the web at
formatting link
or
formatting link
and look for "Into Joy From Sadness" soon.
Reply to
STEAM GENE
"STEAM GENE"
We're not tellin' :-)
Just too bad that the GER doesn't use 2-8-4s.
-- Cheers Roger T.
formatting link
of the Great Eastern Railway
Reply to
Roger T.
Answer is Life Like didn't build enough to supply Standard Hobby Supply with their complete order. Despite ordering it in March, my order was not filled. Gene ABV61-1043.001.HCB
formatting link
"Skinny Dipping and Other Stories" On the web at
formatting link
or
formatting link
and look for "Into Joy From Sadness" soon.
Reply to
STEAM GENE

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.