MRC Prodigy Advance burning out decoders

[rrinker]

 There is no need to mill the frame to isolate the bottom brush of the P2K S1. All it took was a piece of tape.

 One set of feeders? Have you tried the quarter test at all points? If your booster does not trip the circuit breaker with a quarter laid across the rails, you WILL have problems. Do not press on the quarter, just set it on the rails.

                                             --Randy

[1948PRR]

I am willing to bet most brass has a hot chassis. I should have been more specific with the term "isolated". To me, that means both leads on the motor are "isolated" from the frame. I am very familliar with the P2K S1 hot frame situation (among others). That was a fun one to isolate, and required milling out some of the frame.

For reference, I have almost 140 feet of track, and only have one set of feeder wires.

I have only ever lost one decoder. It was in a Bachmann 2-8-0, and it got the motor leads shorted to track power because of a poor solder connection blob from the factory.

[Truck]

If you are saying you connected the two track wires from your controler to one section of 120 feet of track your asking for trouble.  I was tought to run buss wires and put feeders at least every 36 inches and that includes sidings and spurs. I use MRC  Prodigy Adv. 2 and if there is a short it will keep tripping the breakers till the short is remove also the link and power led's will occillate till the short is removed. Same goes fo the first generation MRC Prodigy system I have on a small N scale layout. But I have to agree with the other posts your loco's or track work  should be more focused on for the source of your shorts. 

[rrinker]

 You need to check the locos. Rule #1 is that the orange and grey motor wires must never EVER come in contact with the track, either through a wheel touching the frame or a loose wire or something moving around inside or even a derailed loco with a metal pilot touching the track.

 If the loco is operating normally, a short on the track (like putting a quarter on it) should NOT harm the decoder. But track power to the decoder output side - that's instant death.

                                               --Randy

 

[williamsb]

Thanks for all the tips. I set this layout up quite quickly as my grandson was coming to visit and he had been upset when he went to our old house and the train was gone. It is pretty simple now but we have bigger plans. It is a continuous double track mainline about 40' long each, 2 station stub tracks and 3 sidings about 9' long, approx. 120' track in all. I used #14 wire soldered to the track in one place only.

I removed all engines and checked the track voltage, it is 16 volts AC. With the meter attached I put the metal NMRA gauge on the track.It cut out immediately. There is a pilot light and it goes out and blinks about once a second. The power supply light also blinks. When I shorted out the other mainline, the pilot light and the link light come on and about every 3 - 4 sec the power will come back on to about 2 - 3 volts. I don't know why the difference in the tracks.

I don't know why I am losing decoders when it appears the power is cutting out right away. I suppose I could put a 2 amp fuse in line with the red or black wires but would probably be annoying to have to change a fuse every time I had a short but might be easier than replacing decoders.

Barry

[mfm37]

 What Randy said.

Any voltage fed back to the decoder motor outputs (orange and gray) will instantly kill a decoder. Won't matter how fast the system tries to restore power, it was dead on the first try. Don't ask how I know this.

[jeffrey-wimberly]

 Place a toggle switch in line between the controller and the track. When a short occurs you can turn the switch off and get the loco off the track. When the controller resets the switch will prevent the power from getting to the track and frying your decoder.

[rrinker]

  That will happen with just about anything with a 'hot' chassis - even Athearns. The motor may well be isolated - from the wheels, but if the chassis is one side of the motor and a derailment causes a wheel to touch the track and chassis - poof goes the decoder. This even happens with such locos as the Proto 2000 Alco S-1 switchers - the chassis is normally hot but the motor is isolated from track pickups, until a wheel touches the frame. The recommended fix for that particular loco is to run a new orange wire to the bottom motor lead so it is isolated from the chassis. The same method could be used to fix brass and other locos. If the problem is a wheel bridging between a hot chassis and the track, this is the way to go - truly isolate the motor. This type of short can blow any decoder on any dcc system.

                             --Randy

 

[1948PRR]

Are you sure your motors are isolated? There's a lot of , well, BRASS in those brass locos, you could be shorting track power to the decoder, and not just the wheels. This will definately fry a decoder.

[maxman]

williamsb

I wish the power wouldn't cut back in automatically. Any ideas how to solve this? The system puts out 3.5 amps which is more than the decoders are rated for.

 

I think I'm with the others on this in that you probably have some sort of wiring problem.  But if you really think everything is okay, then you can get yourself one of these:

http://www.tonystrains.com/products/img/showimage.html?PSX DCC Circuit Breaker|dccspec|4|1|psx_2254.jpg|psx_2255.jpg|psx_2256.jpg|psx_2262.jpg|

Looking at the specifications, it appears to be adjustable for four diferent current trip values, including 1.27 amp, and can be configured to require a manual reset.  Instructions are at: http://dccspecialties.com/products/pdf/man_psx1.pdf

[williamsb]

I have burnt out at least 3 decoders. The steam engines are HO Samhongsa from Korea. The decoders are Digitrax. The track and wheels are not dirty, I do not have any loss of power due to poor contact.

On the one steam engine the holes for the tender wheels are too deep and the wheels would occasionally touch the side frame and cause a short across the motor. The system would cut out but after 2 seconds it will reset and if you don't get the engine off the track in about 10 seconds it will have reset about 3 or 4 times and the decoder burns out. The other steam engine had the same type of short through poor insulation of the drawbar.

Another was on a Proto 2000 FA2, not sure what shorted out but the same thing cutting back in several times blows the power to the motor, the lights still work but the engine won't move. I have reprogrammed, reset and they come back to a blown decoder. My original DCC would not reset automatically, you had to do it manually and I never lost a decoder in more than 10 years.

Barry

 

 

[CSX Robert]

williamsb

If one of my steam engines gets a short it cuts out immediately, but it resets itself after about 2 seconds and if it does this several times it burns out the decoder. My older system had to be reset manually and I never burnt out a decoder...

A layout short(i.e. derailment or running a turnout set the wrong way) should not burn out the decoder. Have you tried resetting the affected decoders? Layout shorts will sometimes scramble a decoder's memory(some are more sensitive to this than others). If shorts are blowing your decoder, it sounds like the locomotive is internally shorting the motor or function leads to each other or to one of the rail pickups. If that is the case, then it needs to addressed regardless of whether or not your system automatically restores power. My Zephyr automatically restores power after a short and I have never had a blown decoder due to a short(and yes, I have had plenty of shorts).

williamsb

..The system puts out 3.5 amps which is more than the decoders are rated for.

With a layout short, the 3.5 amps won't matter because the 3.5 amps will not be flowing through the decoder. The only way the 3.5 amps would flow through the decoder is if the decoder loco is shorting out the decoder.

[cacole]

You need to find and correct the problem with the locomotive and stop the shorts from happening.  Poor trackwork could also be the cause.

What makes you think it's shorts and not just dirty wheels or dirty track causing a loss of power?  If the locomotive stalls periodically that's probably from dirty wheels, dirty track, or loose rail joiners, and not a short.  A short would/should cause the DCC system to shut down.

Unless you have poor electrical wiring the DCC system's built-in circuit breakers should prevent damage to a decoder.  There's something very wrong with your wiring or trackwork that's allowing this to happen.

It would also help if you provide more complete information such as what scale and what brand/type of locomotive, and what brand of decoders.  If it's an HO scale Bachmann Spectrum steam engine, for example, you need to check the wiring between the tender and back of the locomotive and make sure they are tightly plugged in.

 

[locoi1sa]

 Barry

 If the loco shorts the layout you must get to and fix the short before the power comes back. When the power comes back the short should trip the booster immediately again.  You may need more feeders or larger buss wires if your booster is not tripping right away. It should not be cooking decoders. Maybe a scrambled decoder every now and then that requires a reset and re program.

       Pete

[williamsb]

If one of my steam engines gets a short it cuts out immediately, but it resets itself after about 2 seconds and if it does this several times it burns out the decoder. My older system had to be reset manually and I never burnt out a decoder.

I wish the power wouldn't cut back in automatically. Any ideas how to solve this? The system puts out 3.5 amps which is more than the decoders are rated for.

Barry