Decoder Issues

[conrail92]

Lately ive been haveing trouble with my one engine i use a prodigy express when i play this locomotive on the track the lights on my dcc system blinks back a fourth and when i take it off it stops and stays solid like its supose too. This usualy only ever happens if two wires on touching i checked the whole track and i checked the decoder wiring nothing is touching but it still does this and only for this engine. can some one please help?

[selector]

It would appear that you have an error in connectivity somewhere on the loco-tender combination. Since both items have pickups (I'm fairly certain), they both are meant to take up power via their wheelsets. So, beginning at the wheels, there are metal brushes or tines that rub against the axle or the rear of the wheels. From there, the tines direct power down their lengths to an eventual wire. That wire is either soldered onto the pickup, itself, or onto a post or retainer that both holds the pickup onto a mounting, and hosts the wire that runs inside the loco and to the decoder. Only to the decoder! From the decoder, wires (I don't know the colours) will go to the motor and to the sound system, if there is one, and also to the lights.

Somewhere along this system, a wire is loose, touching a metal component that it should not, or simply mis-attached in the first place.

You could also have a loco that requires isolating the tender, electrically, from the loco via a non-conducting drawbar. Here is where I am fuzzy, because I don't own such a loco...to my knowledge. On these locos, there is not meant to be electrical connectivity allowed via the drawbar, so you will get a short when things have not been assembled well or are now out of spec due to wear and tear.

Beyond that, I cannot help.

[simon1966]

The DCC system is telling you that there is a dead short in the locomotive/decoder installation somewhere. If it is a steamer, make sure that one of the tender trucks has not rotated 180 degrees putting the wheel pichups from oposite sides on one side.

Did this loco ever work?

[conrail92]

Ok the decoder previously worked in this loco and was working for a while then all of a sudden on day when i was operrating it, it started doing this. for no aparnt reason
it is a digitrax DH163A0
i checked the wiring and nothing appears to be touching

[claycts]

1. This is the ONLY decoder that is this way correct.
2. This happens ONLY on one section of the layout or all over? (rerail at a different location)
3. LOOK UNDER the loco real close, did you pick up some METAL trash on the wheels, trucks.
4. Has the trucks shifted on the bolster (loose screw)
5. UNPLUG the coneection for the engine to the tender, clean and reset it.
6. If over 21 pop a brew and think about it. If under 21 have a Pepsi and think about it.
7. IF you have a VOM (volt, ohms meter) then test for a short on each wire. If you understand a VOM then ignore thic next point. If you ahve a short with the meter set on ohms you will get a ZERO read if you touch the metal frame and then a wire.
The resaon for the thinking is what was it doing BEFORE it stopped working? Running fine, running jerky, stalling? That will give a reference to look back to.
Hope this helps.
Take Care
George P.

[conrail92]

1. This is the ONLY decoder that is this way correct. = YES
2. This happens ONLY on one section of the layout or all over? (rerail at a different location)= all over on any track
3. LOOK UNDER the loco real close, did you pick up some METAL trash on the wheels, trucks. = checked no issues
4. Has the trucks shifted on the bolster (loose screw) = no
5. UNPLUG the coneection for the engine to the tender, clean and reset it. = tender? ..where dealing witha an atheran sd 70 genesis
6. If over 21 pop a brew and think about it. If under 21 have a Pepsi and think about it. = ice tea , cured my thirst didnt solve problem
7. IF you have a VOM (volt, ohms meter) then test for a short on each wire. If you understand a VOM then ignore thic next point. If you ahve a short with the meter set on ohms you will get a ZERO read if you touch the metal frame and then a wire. = dont have one
The resaon for the thinking is what was it doing BEFORE it stopped working? Running fine, running jerky, stalling? That will give a reference to look back to.
Hope this helps. = IT was working fine then all of a sudden it just stopped workin altogether and the issue began

[claycts]

On that Note, Bring me a MICK PLEASE! That is a stumper!
Did the decoder itself go south? That is the next question. A REAL stretch is the brushes on the motor. Have you pulled the shell and turned the motor over by hand one complete revolution? If you feel a bind in the works look at the brushes and gear box.
Should have asked before, by the ID it is a solder on decoder correct? If so did a solder joint fail or touch the frame? Unused wires of the decoder are taped off correct?
Can you TEST it on the bench? test track?
If non of the above then it is J. W. Black on the rocks please!
Take Care
George P.

[Anonymous]

I think something's got to be touching, but without a meter it is going to be tricky. Can you try running without the shell on?

[conrail92]

i turned motor over by hand nothing happened, i tried it on test track nothing happened, no it is not soldered on, I have wires going to the lights the lights are burned out and until i get new ones the wires are disconnected. but there taped so nothing it touching. Ill try to see if my one friend has a volt meter i can barrow from him to test if it works that way. Its starting to get annoying, now say i fried the decoder is there a pacific way of telling if i did or not , just want to see if i can roll that cause out

[M&PWJOHN]

One item I've found to play a bit of a problem is some of the newer (1995) loco's have a different polirity on each tender truck. If this is the case, you can have one side of the loco picking up from one rail and one tender truck also picking up from that same rail. If you have this and happen to misconnect the tender trucks, you build in a short. This is a bit difficult to detect, as if you pick up either the loco or the tender or both the short goes away.

[conrail92]

but could this be the problem if it worked before? it previously worked. then this problem started

[simon1966]

QUOTE: Originally posted by conrail92

I have wires going to the lights the lights are burned out and until i get new ones the wires are disconnected. but there taped so nothing it touching.

Could this be the clue as to what happened? If the bulbs burned out, then there is a very good possibility that the function outputs of the decoder and therefore the decoder itself is fried. What rating were the bulbs that burned out, and what level of resistor, if any was installed in line with the bulbs?

[conrail92]

no the lights where out from the day i put the decoder in, and the decoder worked with the lights burned out

[bp020897]

I had the same problem with one of my locomotives (F7A) and the problem was the decoder plug was not seated firmly in the receptacle. As in it was loose as a goose because I had not pressed it in the socket hard enough when it was installed . Did you try reseating the decoder plug?

Bob

[simon1966]

Ok, so we are still left with a dead short in the loco/decoder somewhere. Somehow you are going to have to isolate the problem. Since you do not have a meter, I think the next best thing would be to place the loco on the track with the shell off. Verify that you still have the short. Then turn off the DCC system and remove the decoder. If the short goes away then the problem is in the decoder/wiring, if not, there is a short between the pickups on each side, most likely thru the frame, or possible the insulation used to isolate the motor has broken down and is causing the short.

[conrail92]

Theres no short detected when the decoder is off, but when i put it back on there is...if that helps any... any chance this is the sign its fried?

[simon1966]

Is it a plug in, or solder in job? If it is a plug in job, look really carefully ar the socket and the plug to see if there is anything that might be causing a short. This could be a particle of stray solder or a filament of wire linking 2 of the pins. If you can't see anything then it really looks like the decoder might be toast.

[conrail92]

its not a plug in, and i was afraid of that how do i go about replaceing it. do i get a free replacment from digitrax?

[simon1966]

Give them a call. www.digitrax.com I find that they are very responsive to phone calls, e-mails can get lost. Let them know when and where you purchased it, and if it is still under warranty, I am sure that they will honor the device.

For what it is worth, although I am a really happy Digitrax systems operator, my decoders of choice are those made by TCS www.tcsdcc.com They have a fantastic warranty that includes replacement of decoders fried due to incorrect installation and user error. I had to avail myself of this as a result of not putting in a resistor in a light installation and burned out a decoder, literally!

[conrail92]

i saw them before i was going to buy from them but i got digitrax, i might buy my next one from them, and ill give them a call later.

[davekelly]

How hard would it be to take the decoder out of the engine and see if it works on DC? Is it possible to jury rig something so you can test the decoder in a different engine?

[conrail92]

no im limited of my amound of locos, and they arent all dcc compatible, im putting most of my money in the track and scenery at moment.

[Anonymous]

How about this...?
Take off the shell, disconnect the red and black wires from the pick-up, and jump them straight to the booster, with no track involved at all? If that works we know the problem is in the frame somewhere, if it doesn't the decoder is getting more suspect.

[conrail92]

ill try that thnx