I have been in this hobby for 10 years now, but I am still encountering firsts. Here is another first for me.
I have a 10 year old Proto 2000 GP9, non-sound loco in which I long ago installed an NCE P2K-SR decoder.
Last week, while trying to track down a short on my layout, I could hear the track beneath this loco buzzing so I removed the loco from the layout. I found some nearby feeders touching the opposite rail with bare wire, so I did a fix and the short went away.
Today, I put the loco back on the track, and a short instantly occurred. Both trucks were shorting the rails. So, I removed the shell and examined the decoder and the wiring. Everything appeared OK. I pulled the decoder and tested it with my decoder tester. Everything checked out fine.
So, I put the original DC board back into the loco and plugged it in to the 8-pin chip. Set it on a piece of track on the work bench and wired up a DC power pack. Tested the track for voltage and that was good. Tried to run the loco, nothing. I removed the loco and clipped a 12 volt incandescent bulb to the rails and it lit brightly. With power on from the DC power pack and the bulb glowing brightly, I set the loco on the track and the bulb went out. Took the loco off the track and the lamp came back on. Put the front truck only on the track. Went dead immediately. Put only the rear truck on the track and the lamp stayed on, but only for a few moments and then went off.
What is going on here? Any ideas or suggestions?
Rich
Alton Junction
The Proto 2000 Geeps use the chassis as a ground. Check the wiring to make sure nothing is inadvertantly touching the chassis ground from the opposite rail. This is strictly a divide and conquer proceedure. Remove both trucks from the chassis and see if either truck will short out the rails on its own. Check the wiring for any worn insulation. A truck wire that may have been rubbing on the chassis may have finally worn through and is shorting out on the chassis.
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
Rich,
Just a long shot, but with all the moving around you did, it's a possibility, that now one of the wheels sets, the axle's are touching in the gear. Do a continuity test, wheel to wheel on one axle, should not get a reading, if they are not touching.
It happens.
BTW. While you are at it, check for a cracked axle gear. IF you recall, I changed all my GP7's gears, they were cracked, just sitting for a period of time.
Frank
EDIT: Athearn part# ATH 60024, perfect match, 6 per pack.
Yeah, that's true. Cracked axle gears are very common on those engines. A cracked gear could easily cause one axle to move inboard and short out against the opposing axle.
If you haven't already replaced all the gears, now would be a good time to do it.
zstripe Rich, Just a long shot, but with all the moving around you did, it's a possibility, that now one of the wheels sets, the axle's are touching in the gear. Do a continuity test, wheel to wheel on one axle, should not get a reading, if they are not touching. It happens. BTW. While you are at it, check for a cracked axle gear. IF you recall, I changed all my GP7's gears, they were cracked, just sitting for a period of time. Frank
Oh, this just isn't right. How could Frank solve my problem? LOL
Frank, u da man !
And, Mark, thanks for your suggestion as well. Before I attempted to remove the trucks from the chassis, I decided to try Frank's idea first. I did a continuity test after popping the wheelsets out of their gear housings. The front wheelset of the front truck was the culprit.
This loco, CNW #1720, is the mate to CNW #1719 in a consist that I run. Back in January, I replaced cracked gears in CNW #1719 and, at the same time, I checked the gears in this loco, CNW #1720, as well. The gears in this loco are fine, but if you press these split axle wheelsets too firmly, both of the axles will touch. That is what happened here. I slightly pulled the axles apart without throwing the wheelset out of gauge, and that did the trick.
Frank, I owe you one.
Pushed in as far as they go, such that they cause a short, they will be way narrow on the NMRA gauge. It's almost good this causes a short and the loco won;t run - if it did, it would probably derail on anything more complex than a basic turnout.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Stupid design, though.
I recall now that in January when I checked out all of my Proto Geeps for cracked gears, I pushed the wheels in too far and caused shorts on a couple of them.
Split axles have been around since, hmm, at least the first gear drive Athearn Blue Box locos, and likely before that. The alternative, used on train set quality stuff from Tyco and LifeLike, was to make one wheel plastic. Just insulating at the hub of one wheel like is often done on metal wheelsets wouldn;t hold up - on a piece of rolling stock, the wheels are along for the ride and don;t carry much force, but on a loco, the pully power is transmitted through there and you wouldn;t want the wheel to spin on the isulator and only the one side actually pull the loco. Not sure how else you would pull off powering the axle while also having metal wheels and oh by the way keep it insulated for 2-rail use.
Well, OK, so maybe not a stupid design.
But, definitely something to keep in mind when examining or replacing cracked gears on Proto Geeps.
Don't press those wheels together too firmly.
That's why everyone should have an NMRA gauge. I don;t like to take things apart over and over again, so as part of installing a decoder in my P2K Geeps, I put in LEDs for the lights and repalce the gears with the Athearn ones. Even if they aren;t currently cracked - they eventually will. It's pretty close to correct if some of the axle shows on each side, but I check them all before installing. The other thing to keep in mind is you want to keep the gear centered - so pull out each side equally, don;t keep one pushed all the way in and back out just the other one.
rrinker That's why everyone should have an NMRA gauge.
That's why everyone should have an NMRA gauge.
You mean, that's why everyone should use an NMRA gauge.
I have one, but I didn't use it.
Shame on me.
I had one that had the axle pushed all the way into the gear shaft and the other side wasn't and it still shorted, wheels in gauge, out of the box, brand new. There must be at least, a 1/32 space on both sides of the axle gear. Three weeks ago, I replaced, 24 axle gears.
I hope you can still respond. I just bought a Proto 2000 E6 on e-bay. It was brand new still in it's original wrappings. I run analog. It has run great for a week. Two days ago it stopped. On the track, it shorts everything out. When I reset the Kato power pack everything runs fine. I hope you can help me fix my E6.
Thanks!
to the forum and you are in luck, Rich is still around, ready to help. However it costs nothing to start an new thread and if you are not asking which DCC system is best, no one will give you a hard time for starting anew.
This thread is pretty clear. The half axles in each truck can touch if the the wheelsets are not in gauge and too close together. I'm not sure the E6 is the same as the GP9, but manufacturers don't try to reinvent the wheel with every new model.
Gear cracking is a known problem with many of the Proto diesels and that could lead to your problem
Have you checked the wheels with the NMRA gauge? According to other threads, the E6 uses a different wheel set that the GP, if you need to replace them. Since your loco worked for a while then stopped, I think we can assume something broke.
Walthers
EDIT this has a good pic so I will put it back in my post
http://cs.trains.com/mrr/f/88/t/257955.aspx?page=2#3117578
Henry
COB Potomac & Northern
Shenandoah Valley
Gator Marty I hope you can still respond. I just bought a Proto 2000 E6 on e-bay. It was brand new still in it's original wrappings. I run analog. It has run great for a week. Two days ago it stopped. On the track, it shorts everything out. When I reset the Kato power pack everything runs fine. I hope you can help me fix my E6. Thanks!
I don't like You, either Henry!........LOL
Take Care!
zstripe I don't like You, either Henry!........LOL Take Care! Frank
WOW! Some friend You are Rich.....now everyone knows, I was in prison....
Take It Slow..........
Frankie
richhotrain Henry could not be sure if you were still in prison Rich
zstripe WOW! Some friend You are Rich.....now everyone knows, I was in prison.... Frankie
Oops, sorry Frankie, I meant to say that Henry didn't know whether you had taken poison, not prison.
Richie