TheRailwire
General Discussion => DCC / Electronics => Topic started by: Cajonpassfan on November 12, 2015, 01:49:39 AM
-
I spent the entire day today, my day off, (not counting countless frustrating hours over the course of a year) chasing down a short on one of my power districts that had made the central portion of my layout inoperable and the rest of the layout pretty much useless. I tracked every hard to get to connection under scenicked portions of the layout, pulled off scenery, disconnected and unsoldered many blocks, cut wires to narrow down the problem, took the Ohm meter around inch by inch, and finally found the culprit: a sloppy loose edge connector on one of the 100 or so Tortoises I have that bridged the Tortoise contacts, below :scared: :scared: :scared:
I should be thrilled I finally found the problem (and I guess I am) but I am so royally pissed at myself (and the manufacturer) for creating such a stupid simple but deadly malfunction.
I think I'll celebrate tomorrow; tonight I'm just tired...
Good night, Otto
-
Reminds me of an incident I had on TBC a few years ago where I somehow managed to get a steady 12 V across my (then-DC) rails via a Tortoise. I don't remember how it happened, but it was kind of spooky to see my locos tear off like a bat out of hell!
Model Railroading is Fun.
-
Model railroading IS fun; it's the flipping' wiring is not :scared:
So I can't believe I'm the only one with this problem. Is there a simple way to prevent the edge connectors from sliding laterally? Do I need to put nonconductive shims inside the connectors? Or do I just hardwire future installs like I used to before I "discovered" the edge connectors? If the Tortoise card were just a bit wider, this wouldn't be an issue.
These are the ones I'm using, see below...
Otto K.
-
On some of my connectors I've glued in a styrene shim to prevent misalignments. The rest are a problem waiting to happen.
What it really means is that the connectors are the wrong spec for the Tortoise. Does anyone know of the correct one?
Ed
Edit: makes me long for the day when we can have dead rail in N scale :ashat:
-
This has been a pet peeve for me that the board doesn't match the size of standard connectors. The usual fix is to glue a piece of strip styrene into the connector on each side to keep it centered on the tortoise's edge connector. I have heard that somebody has created a connector that matches the size, if I can find it I'll post it
Lyle
-
I've never used these, but swore I've seen the styrene shim trick in an article before.
-
I had a very similar experience last week. Turn on the layout and "click--click--click--click". After about half an hour, I traced it to.... A Tortoise! One strand of a stranded wire had come lose and wandered over to make contact with its neighbor.
-
Easiest solution: don't use edge connectors (they are really a kludge, not specifically designed for the Tortoise's circuit board). My Tortoises are wired with 5 wires (M+, M-, Track+, Track-, Frog out). Before I install them, I solder five 18" lengths of color-coded wire to the appropriate terminals (red and black for track power; yellow and blue for motor; green for frog out). Once the Tortoise is in place, I complete the wiring by using half of a 12-position European-style terminal block (Digikey, $2.20 in lots of 10, so $1.10 for each Tortoise). The wires from the Tortoise go in the top of the terminal block, the supply wires in the bottom. Easy to disconnect if I need to replace the Tortoise, and easy to disconnect individual wires for troubleshooting if necessary. Never, ever had a wiring problem this way.
John C.
-
John, NOW you tell me :D
This sounds like a great way to go, before one installs a hundred of them :facepalm:
Otto
-
John, NOW you tell me :D
This sounds like a great way to go, before one installs a hundred of them :facepalm:
Otto
Well, heck, I thought everyone did it this way :D
John
-
This has been a pet peeve for me that the board doesn't match the size of standard connectors. ...
Oooo, that's disappointing. I haven't used Tortoises so can't speak directly... but a connector mismatch like this is a basic design error. It easily could be they designed the board/edge connector around a specific brand and type of connector that was discontinued, or after tooling the board, changed connector source. However, it seems odd to me as a former designer of such things that there would be that much difference between 0.1"-pitch edge connectors. This connector type has been around for over half a century, and with that I tend to think that the specs are pretty cut-and-dried.
Then again, as John inferred they were not designed for edge connectors, it was just "lucky" that the wire solder pads were on 0.1" centers and could be used with modified (the styrene shim) edge connectors. As are all things hobby related, it's an issue of cost sensitivity - including the connector with the device would increase the end-user cost by about $1.50... or more, considering that solder-tab edge connectors are an electronics-design dinosaur. :|
Aaaaaaaanywaaaay... as we incorporate more and more electronics into our MRRs, folks are going to discover one of the truisms from my too-long career in electronic devices: the #1 source of failures is connectors, and flakiness thereof. ;)
-
OK, this doesn't reassure me about my upcoming under the layout adventures, DCC and otherwise, at all. :scared:
-
OK, this doesn't reassure me about my upcoming under the layout adventures, DCC and otherwise, at all. :scared:
I've learned the hard way that using the European-style terminal blocks EVERYWHERE is the best insurance against wiring problems. I use them for the Tortoises, but I also use them for feeder wiring and for wiring the main bus between isolated sections of the layout. It's a bit of a pain, but I use a standard 12-position block for track feeder wiring, one block for red and one for black. I connect the track power to the top, daisy-chaining 1" lengths of 20-gauge SOLID wire across all 12 positions and feeding from the far left or right as needed, and then use the bottom portion to connect individual feeders. If I have a short, I can undo the feed wire in 5 seconds, disconnecting all the feeders. If that fixes the short, then I reconnect the main feeder, and unhook all 12 feeder wires. Then I hook them back up one-by-one until I find the short.
Here's a photo that shows both the Tortoise wiring and my feeder wiring (I'm not a neat freak, so be forewarned that there are wires everywhere):
(https://lh5.googleusercontent.com/-ObWnxv6zSGc/TgVHEY52hcI/AAAAAAAABiw/q5nU05Lpp9Q/w981-h654-no/IMG_5195.jpg)
The thick red and black wires are the bus wires connecting this isolated section of the layout. Disconnecting one of these disconnects the entire layout section. The individual Euro terminal blocks are wired together with the short 1" daisy-chained wires, and the feeders come off the bottom.
And . . . I always use only SOLID wire for layout wiring. Stranded wire has its uses, but there are too many opportunities for a stray strand of wire to cause problems under a layout. Even my 12-gauge bus wires are solid copper. They are not exactly flexible . . . but they get the job done.
John C.
-
OK, this doesn't reassure me about my upcoming under the layout adventures, DCC and otherwise, at all. :scared:
Peter, you'll be fine, really :P
John's advice about using terminal blocks is actually very practical. Aside from the edge connector problem, every time I have an issue is where I was cutting corners. The terminals make troubleshooting much easier; I had to cut some wires. The other (obvious) suggestion I'd make is to get most of your wiring done before too much scenery goes in. Amazing how much easier it is when you can actually see it and get to it :D
Best, Otto K.
-
Here is an example of the way my friend hooked these up under his layout. He soldered color-coded wires to the tortoise connecter and used crimp terminals on the other end. Then they are attached to the terminal blocks. This is a very reliable solution and it makes it easy to troubleshoot any problems (since each wire can be individually detached from the terminal block).
[attachimg=1]
[attachimg=2]
I also think that the edge connector was an afterthought rather than a design feature. If it was a design feature then I think that the circuit board would have been made wider to better fir the connector. But if you want to continue using the edge connectors then installing styrene strips to properly align it with the circuit board is a viable (and easy) workaround.
-
I'm with JD :D Euroconnectors make wiring and cabling much easier to organize and trouble shoot. Here's an example of how I used them to wire a G-scale layout I automated several years ago. The first image is of a card rack of BDL168's. The connectors made connection a snap. The second photo is a breakout board for an SE8C. Again the connectors made the connections easy to make and edit.
Lyle
(http://a4.pbase.com/g10/64/1272964/2/165987441.iHQqc3Bo.jpg)
(http://a4.pbase.com/g10/64/1272964/2/165987381.ViaB7fC9.jpg)
-
Lyle, that's just sick, I mean slick. :o
Do you have time to come over this weekend?
Otto K.
-
Hi Otto. Pity you have had such a bad time with your short. When wiring all of my over 100 tortoise machines I drilled a slightly larger hole in the board and inserted all of my 8 wires in from behind. Then using a very hot small tipped iron and a good quality R/C solder applied a good fillet of solder to the board and wire. I then made sure that each joint was clean and no tracers present.
Then all wires (about 8 inches in length) were terminated into a very good quality terminal strip. All other wires were then attached to the terminal strip.
Saved a heap of trouble during installation.
Rod.
-
I'm with JD :D Euroconnectors make wiring and cabling much easier to organize and trouble shoot. Here's an example of how I used them to wire a G-scale layout I automated several years ago. The first image is of a card rack of BDL168's. The connectors made connection a snap. The second photo is a breakout board for an SE8C. Again the connectors made the connections easy to make and edit.
Lyle
(http://i622.photobucket.com/albums/tt307/l_dowell/Alpine%20Layout/HPIM1913_zpsxncnfjo5.jpg)
(http://i622.photobucket.com/albums/tt307/l_dowell/Alpine%20Layout/HPIM0659_zpsnzlu58mz.jpg)
This is what I meant when I said I'm not a "neat freak." Jeez, this looks like something from NASA, not a model railroad!
John C.
-
Easiest solution: don't use edge connectors (they are really a kludge, not specifically designed for the Tortoise's circuit board). My Tortoises are wired with 5 wires (M+, M-, Track+, Track-, Frog out). Before I install them, I solder five 18" lengths of color-coded wire to the appropriate terminals (red and black for track power; yellow and blue for motor; green for frog out). Once the Tortoise is in place, I complete the wiring by using half of a 12-position European-style terminal block (Digikey, $2.20 in lots of 10, so $1.10 for each Tortoise). The wires from the Tortoise go in the top of the terminal block, the supply wires in the bottom. Easy to disconnect if I need to replace the Tortoise, and easy to disconnect individual wires for troubleshooting if necessary. Never, ever had a wiring problem this way.
John C.
I agree that this sounds like the way to wire up Tortoises. As usual, John's idea is simple, and takes care of real-world potential problems.
I can only add one more thing, and that is to ALWAYS use solid, non-stranded wire when soldering wires to Tortoise terminals. We've got one anecdote here how strands seem to "sneak" out and cause shorts, and solid core wire, the protruding ends snipped off close, will put an end that that problem.
I also had a "short from Hell" when I removed my rat's nest DC wiring, and replaced it with highly organized (for me) and standardized DCC wiring after installing a 22AWG feeder on EVERY stinking piece of rail up top. Not following my own advice and logic, I did not check each and every new connection I was making as I connected the feeders to my sub-buses...then connected the sub-buses to my buses. Luckily, I am using genuine 3M Scotchlok connectors (suitcase connectors) for every track power connection minus the soldered joint at the underside of the rail feet, so I was able to disconnect my connectors in an attempt to isolate the short. Soooo...with EVERY wire disconnected, I still had the short!! Finally, I found it (after three 12 to 14 hour days!!!) and it was a broken PCB throwbar up top that I'd unknowingly broken when tipping my section up on its side to get at the wiring underneath! This was on the first of my six old-DC-wired sections, and following my "check-every-joint-and-connection-when-you-make-them" protocol, the other five sections got re-wired without incident.
However, during this process, I discovered that at least half of my Tortoises' soldered connections were either loose or coming loose. I had not secured the wires in any significant or organized way, and since my layout is portable, a lot of vibrating and banging around goes on in 200 miles riding in a U-Haul trailer three times a year, and the weak point of course is the soldered joint...especially those that connect floppy wires to solid pads. I had done some wiring joints using suitcase connectors on power-routing circuits, and none (ZERO) of these had loosening or non-conductivity problems...only my soldered joints, mostly at my Tortoises or at my SPDT toggle switches.
This observation led me to organize my DC buses and associated wiring, making sure I secured the wires within 6" of the Tortoise and toggle switch connections with either a zip-tie or simply gluing the wires to wood or Masonite with thick CA (I was in a hurry, getting ready for a show), which, in the 6 years since converting everything to DCC, seems to have cured the loosening/oxidizing problems I had before in my portable sections.
However, if I had had John's suggestion in my consciousness 25+ years ago when I started using Tortoises and wiring them up, it would have solved several problems I've had to deal with over that quarter of a century! JEEZE...getting OLD!!
Just to join the fray, here's a photo of my new, non-rat's-nest DCC wiring on one of my Echo Yard sections. After reading this thread, I'm seriously considering totally re-doing my Tortoise wiring to make it neater...
(https://lh3.googleusercontent.com/-pUsQ0GoqHXw/UECKS7vjVqI/AAAAAAAADbU/OoaS9yhm9Q4/s000-Ic42/WiringDONELastUnit003.jpg)
Cheerio!
Bob Gilmore
-
Although I don't use the connector for the Tortoise soldering tab on my layout, it appears that maybe there's a fairly simple solution to the registration and slippage-shorting problems just waiting to happen.
Looking at the photo of the connector and reading that the shorting problems are caused by too much "slop" between the outside edges of the Tortoise soldering tab and the inside edges of the connector, allowing the connector to shift and possibly short.
I also get from reading that there is probably not enough room inside the connector for plastic shims, which means the problem is twofold...too tight tolerances between connective tabs inside the connector, and too loose tolerances on the inside edges (which register the connector's tabs to the soldering pads on the Tortoise).
I also get that shifting the connector from side to side only a few thousandths of an inch one way or the other might result in a short, which means the tabs in the connector are probably too wide to be 100% compatible with the Tortoise solder pads.
Generally, the connectors won't short (which is my assumption because they continue to be sold and used mostly successfully), so the problem appears to be sporadic, but definite, and are probably caused by differences in manufacturing/assembly tolerances in both Tortoises and connectors...meaning that shims of a certain thickness, placed in the same way in every connector probably won't solve the problem.
Hmmmm....okay, if the plastic is thick enough on the narrow sides of the connector, I'd say that drilling and tapping small holes to accept small diameter set-screws (or machine screws) would offer both adjustment and security for positioning of the connector relative to the Tortoise soldering pad tab. If you do your wiring connections to the connector and press it onto the Tortoise soldering pad tab...and it works, then adjust each set-screw inward to bear on the edges of the Tortoise soldering pad tab, properly securing the connector in the correct position and not allowing it to shift sideways in the future and cause a short. It's anybody's guess which direction the connector, if shifted sideways, would cause a short, so adjust both set-screws inward to "verify" the registration between connector and Tortoise soldering pad tab since it's working.
If the connection shorts after attaching wires to the connector and pressing it onto the Tortoise soldering pad tab, then shift it sideways until the short opens...retest to make sure, then adjust the set screws accordingly.
Again, this is dependent on if the plastic on the sides of the connector is thick enough to accept a small threaded hole. You could use small machine screws instead of set-screws which might make them more convenient to access and adjust with a screwdriver. If there's a problem inside the connector with using metal screws, maybe small Nylon screws would work just as well.
Cheerio!
Bob Gilmore
-
I started using ribbon cabling, break it out into a group of 4, then the outer wires are tortoise power and the inner ones are from frog polarity. pretty simple to wire up and keep organized. A few photos
(http://i1324.photobucket.com/albums/u602/57miguel/panels%20and%20wiring/DSCF4195_zps5ajymdu9.jpg)
(http://i1324.photobucket.com/albums/u602/57miguel/panels%20and%20wiring/DSCF0257_zpstlae7m16.jpg)
(http://i1324.photobucket.com/albums/u602/57miguel/panels%20and%20wiring/DSCF0261_zpsicm7pyfo.jpg)
(http://i1324.photobucket.com/albums/u602/57miguel/panels%20and%20wiring/DSCF0243_zpshfbigtge.jpg)
-
At the club we solder something like this to all our Tortoises.
https://www.phoenixcontact.com/online/portal/us?uri=pxc-oc-itemdetail:pid=1727078
If anyone wants confirmation of the exact part we use I can find out, but it looks real similar.
-
Wow, some of you guys do some real quality electrical work....
Im not giving up on edge connectors with the styrene shim trick. I like the ability to just isolate the entire Tortise for trouble shooting with a quick tug... without having to utilize additional tools.
Jeff
http://espeeoregondivision.blogspot.com/
-
Wow, some of you guys do some real quality electrical work....
Im not giving up on edge connectors with the styrene shim trick. I like the ability to just isolate the entire Tortise for trouble shooting with a quick tug... without having to utilize additional tools.
Jeff
http://espeeoregondivision.blogspot.com/
Yeah Jeff, I'm inclined to agree, there's something about just "pulling the plug". Still, the damn edge connector gave me bunch of grief. Now that I understand the issue, I know what to look for.
And if my layout wiring looked as pretty as some of the guys' work here, like Lyle's, I think I'd just turn it upside down, scenery and all, and call it a day :D
Otto
-
And if my layout wiring looked as pretty as some of the guys' work here, like Lyle's, I think I'd just turn it upside down, scenery and all, and call it a day :D
Otto
+ :D
-
And if my layout wiring looked as pretty as some of the guys' work here, like Lyle's, I think I'd just turn it upside down, scenery and all, and call it a day :D
Otto
Thanks Otto, I am appreciative of the compliment. :) I had the luxury of time, and made good use of it
Lyle