I never paid much attention to the turntable but we also have a transfer table on the club layout that I monkeyed with for an hour or so at one of the shows trying to get working, and it seemed like on that control box, if you were on say track 2 and wanted to get to track 6, you could press the up arrow 4 times and it would run right to 6 without stopping in between. I thought the turntable (non-DCC one) worked the same way, you could press the button multiple times and it would run up to the number selected before stopping.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
rrinker I never paid much attention to the turntable but we also have a transfer table on the club layout that I monkeyed with for an hour or so at one of the shows trying to get working, and it seemed like on that control box, if you were on say track 2 and wanted to get to track 6, you could press the up arrow 4 times and it would run right to 6 without stopping in between. I thought the turntable (non-DCC one) worked the same way, you could press the button multiple times and it would run up to the number selected before stopping. --Randy
Rich
Alton Junction
Mike
It has been several years since I disabled the indexing feature and began to operate the non-DCC turntable "manually" by simply holding down the button on the control box until the turntable rotated to the desired position.
So, I went back this morning and dug out the Walthers instruction manual. On the non-DCC version, there is a plastic control box with two "arrow" buttons that control rotation of the turntable bridge track. The LEFT ARROW rotates the bridge track clockwise and the RIGHT ARROW rotates the bridge track counterclockwise.
Here is how the pertinent section of the instruction manual reads: "Use either ARROW button to turn the bridge: press and hold the button to pass stopping positions. As the bridge approaches the desired service track, release the ARROW key. The bridge will overrun the stop position slightly, then align itself."
So, as long as you hold the ARROW button down, the bridge track will continue to rotate past other programmed positions. But if you just press and release the ARROW button, the bridge track will stop at the next programmed position. I recall that is what prompted me to disable the indexing feature. Since I had to stand at the control box and continue to press the button until the bridge track reached the desired position, what was the point of the indexing feature, particularly since it often resulted in a slight misalignment causing derailments?
The whole purpose of the indexing feature on the non-DCC version is to spare the operator the need to stand over the turntable trying to align the bridge track in the desired position. But if the indexing feature misaligns the bridge track, then the whole purpose of the indexing feature is defeated.
I see. Completely understand your frustration with it then. On my new one, the control box has buttons for clockwise, counter-clockwise, head, tail, and track. When you first drop it in, you send it go through a homing sequence to find it's reference point. You then rotate it to the track you want to call "1" and program that point, go to "2", and so on. In operation, you press the "track" button, use the "clockwise" and "counter-clockwise" buttons to pick the track number, then press the "head" (control booth end) or "tail" (opposite of control booth end) and it takes off, moving non stop until it lines up the selected end with the selected track. I bought mine at first release (pre-ordered even) and have yet to have an issue with it. I think Walthers is selling the new controls for use with the older models, but I may be wrong. Might be worth a look though.
*Edit* A quick check of the Walthers page shows the control for use with specific turntable kits, so apparently not all of the previous built up ones?
I noticed a recent Walthers ad that mentions all new turntables with improved electronics - so I guess this will be verion 3? There was the original one, then the DCC version, and now this announced new one.
I think there can be a lot of reasons for misalignment. Several folks have mentioned the possibility of debris in the rack and pinion. Certainly a possibility, however when I ran my all afternoon tests to document alignment errors, my rack and pinion were absolutely sterile, and I still could not get a repeatability better than about +/- .015 inch; sometimes worse. When you look at that system there are three gear meshes (2 worm and the rack and pinion). Those all must have some backlash. There is also necessarily some bearing clearance. I'm not sure how the counting is done, but may be a potential for errors. The actual pulse generation is a light chopper. In my mind one of the more suspect places for error is in the homing switch. That is a photo switch (probably IR) system. It is fairly small (about .050 opening) but switching based on a photo switch is still a somewhat "fuzzy" proposition. In my working career, I designed automation equipment for over 30 years, and used many photoswitch installations. As a rule I would not expect the positioning of a device based on a photo switch signal to be better than +/- .015 inch and that was with photoswitching devices that cost more than the our entire turntable. It appears different versions of the Walthers turntable have somewhat different control logic, but mine rehomed with every revolution of the bridge. Now consider the possibilities of homing errors, particularly when homing may occur from either direction, and it is probably not suprising that there is misalignment. Alignment can be no better than the repeatability of the homing process.
Certainly the debris in the rack and pinion is something to be controled, however in my experience if debris such as ballast causes the problem it is very obvious. I actually put some ballast in the rack to observe it. When the pinion runs over that ballast there was a very noticable jump on that end of the bridge. Also we should consider the pitch of that gear system. It looks to me like the rack has about a .060 inch pitch, so if debris caused the pinion to "jump a tooth" we should see a very large, about .060 ' alignment error. I have never seen that large of error other than when I intentionally forced it.
Eccentricity in the bridge has also been mentioned. No doubt that can cause issues. As others have mentioned, I think the way to get around that is not to use stop 1 and 2. You can program that error out everywhere else. Actually, for an injection molded part of that size I think expecting eccentrity much better than.010 is kind of a stretch.
That is why I went to the decoder control of the bridge motor. I control the bridge with a throttle and as such can stop in virtual perfect alignment, regardless of bridge molding errors, or any of the other errors mentioned. Of course if you can't see the rails well, you are probably pretty much stuck with the Walthers control system.
steering wheel angle inclination sensors.............
Been around in autos for quite some time now.
Wonder why they didn't do that in th first place. Hall effect sensor with a metal wheel with nitches to indicate position in degrees.
I swear manufacturers just forget KISS anymore.....
RVFLYER I had the same problem. I spent an entire Sunday afternoon documenting move accuracy. I found most moves varied about .015 inch mismatch at the rail head; occasionally twice that. I could also document about .005-.010 inch eccentricity. If you are DC my solution is not appropriate. I finally took the entire Walther's control system out and replaced it with a DCC Decoder (Digitrax DH126D). I used the existing Walther's contact wipers to bring power up to the bridge track. I actually doubled up on contacts since there are four rings and now I only need two coonduction paths (you have to connect the two halves of the outer ring). I then used a Digitrax automatic reversing unit (AR-1) to take care of the phase reversing when the bridge reverses. The motor drive is a double worm drive so on speed step one or two, the bridge creeps extremely slow so it is possible to get perfect track alignment. In my case, speed step 30 exactly duplicates the normal Walthers speed. The other advantage I now have, is that I don't get that sound and light shutdown as the bridge rotates through the dead zone as was necessary in the Walthers arrangement. Of course you have to be close enough to see when rails are aligned.
I had the same problem. I spent an entire Sunday afternoon documenting move accuracy. I found most moves varied about .015 inch mismatch at the rail head; occasionally twice that. I could also document about .005-.010 inch eccentricity. If you are DC my solution is not appropriate. I finally took the entire Walther's control system out and replaced it with a DCC Decoder (Digitrax DH126D). I used the existing Walther's contact wipers to bring power up to the bridge track. I actually doubled up on contacts since there are four rings and now I only need two coonduction paths (you have to connect the two halves of the outer ring). I then used a Digitrax automatic reversing unit (AR-1) to take care of the phase reversing when the bridge reverses. The motor drive is a double worm drive so on speed step one or two, the bridge creeps extremely slow so it is possible to get perfect track alignment. In my case, speed step 30 exactly duplicates the normal Walthers speed. The other advantage I now have, is that I don't get that sound and light shutdown as the bridge rotates through the dead zone as was necessary in the Walthers arrangement. Of course you have to be close enough to see when rails are aligned.
RVFLYER,
Can you provide photos and a wiring diagram of your installation. I was planning on doing this myself with both my 130' and 90' turtables.
I haven't figured out how to add pictures to this. If you want to email me at mlewis@cfu.net I can send you a couple photos and wiring diagrams. In general, I cut the wiring to the Walthers circuit board and removed the board. I also removed the light chopper disc from the motor shaft. You will have to use some sort of continuity tester (beeper, light, or ohmmeter)to determine which wires are connected to which ring on the slip rings. I used wires from the inner two rings to connect to one rail, and the outer two rings to connect to the other rail (you need to disconnect the original wires that are connected to the rails). I then just wired the DH126D to the rails, and to the turntable motor per Digitrax instructions. You then need to identify the wires in the original cable that ran from the pit to the Walthers controller. I cut that cable about a foot from the center of the pit, and then removed about two inches of the jacket, so you can spread the individual wires out. Again, use a continuity tester to identify which wire is connected to which wiper. (they are in pairs). You can then assign all the wires coming the inner two rings to one new wire, and the wires from the outer two rings to another new wire. (Shrink tube them up). Now you connect those two new wires to the terminals on the AR1 labeled "out to reversing section". Then connect the terminals on the AR1 labeled "Track A and Track B" to your rail buss, or booster etc. That's all there is to it. Glad to send you photos and diagrams if you email me, (or if you can educate me on how to get them in here!
RVFLYER I haven't figured out how to add pictures to this. ... Glad to send you photos and diagrams if you email me, (or if you can educate me on how to get them in here!
I haven't figured out how to add pictures to this. ... Glad to send you photos and diagrams if you email me, (or if you can educate me on how to get them in here!
--Steven Otte, Model Railroader senior associate editorsotte@kalmbach.com
In his two previous posts in this thread, RVFLYER described replacing the Walthers DCC controller with a conventional DCC encoder, thus converting the turntable from an indexed device to one that the operator positions directly. I too became frustrated with fumbling with the awkward control and standing and waiting for the controller to misposition to the requested index, so I successfully undertook the conversion as described by RVFLYER.
I am very pleased with the result. My turntable is near enough to the layout edge that I can accurately sight and position the bridge using my throttle, and there is no more dead zone disrupting the sounds from the loco on the bridge. Control is very precise with the default motor CV settings.
With his permission, here are the photos and diagrams described in RVFLYER's posts above:
I used an inexpensive Soundtraxx Econami decoder salvaged when I retrofitted a better decoder into a Walthers diesel.
Instructions for disassembling the Walthers bridge, and in particular for popping the center rings circuit board can be found here: http://www.nyrs.com/docs/App4_WalthConv.pdf
Here is a picture of how I implemented RVFLYER's circuits on my ring board. I removed all the wires from the back of the board, and resoldered new wires in their place. The correspondence between the soldering pads and the rings on the other side are obvious. Do not be confused by the orange and blue wires on the ring with the orange and blue wires I connected to the motor. On my bridge, Walthers used orange and blue for the rail wires, so the ones you see on the ring circuit board are the rail leads. The orange and blue wires you will see the bridge photos that follow run from the motor on the left to the decoder on the right with no contact to the rings.
And finally here are some photos of my final retrofitted bridge.