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Turntable Ring Gap Causes BLI Decoders to Stop

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Turntable Ring Gap Causes BLI Decoders to Stop
Posted by rettop on Saturday, February 18, 2017 2:38 PM

I use the last generation of Walther's turntable although I suspect the brand new ones must have the same ring gap. The problem is that the BLI Paragon 2 & 3 locomotives on the turntable as it rotates and crosses the ring gap, the loco's stop producing sound and must have a speed input to get them back to life. This requires some careful manipulation to keep the loco on the bridge and fouls the whole sound effect.

I'm wondering if capacitors can be added to the turntable to eliminate this problem? I think this could work as the "gap time" is very short. I have no idea where one would attach the keep alive capacitors. Walthers answered this question with a single statement about voiding the warranty. I would really appreciate some advice on this- other model railroaders must experience the same problem. Thanks in advance.

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Posted by BMMECNYC on Saturday, March 11, 2017 8:03 AM

rettop
I'm wondering if capacitors can be added to the turntable to eliminate this problem? I think this could work as the "gap time" is very short.

Not easily.  The power is brought up only through the center bolster of the turn table.  This would require dissassbly of the bridge (waranty voiding).  You would have to disconnect the wires from the track and route them to the capacitors.   The reason for the gap is so you dont dead short at the exit of the turntable (also why there is a no track area on the drawing).  It is a manual reversing circuit. 

I suspect that if you were to keep the tracks live with a capacitor, you would end up with a momentary short circuit when the power reconnects.  This will have the same result as before, execpt your command station shuts down. 

I dont know if you can install keep alives in BLI decoders. 

Rule 108: In case of doubt or uncertainty, the safe course must be taken.
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Posted by rrinker on Saturday, March 11, 2017 10:19 AM

 You can add keep alive capacitors to any decoder, it's just a matter of finding the right place to connect. Since the BLI decoders are somewhat more proprietary than others, this may not be quite so easy, but the basic circuit at a high level has to be similar to other decoders as far as having the bridge rectifier as the first thing in from the track pickups. There are likely existing capacitors designed to keep the sound system going, but the probably aren't big enough to clear the turntable gap. For a case like this, you don't really need a huge keep alive that also powers the motor, so it MAY be possible to increase the existing capacitors just to keep the sound on.

                             --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by MisterBeasley on Saturday, March 11, 2017 10:57 AM

Can you bypass the split-rings somehow and just run the turntable bridge through and auto-reverser?  That should give you a faster polarity flip, and the flip will occur when you enter or leave the bridge so the engine will be in motion as it happens.

It takes an iron man to play with a toy iron horse. 

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Posted by rettop on Saturday, March 11, 2017 11:53 AM

BMMECNYC

   (also why there is a no track area on the drawing)

Thanks to you and the others who posted comments. I would appreciate some clarification of the above please. Thanks.

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Posted by rettop on Saturday, March 11, 2017 12:01 PM

Thanks for the comment. Indeed there are existing capacitors. Attaching an additional capacitor is, according to BLI, a warranty breaker nor will they offer any real comments on this dilemma. The 2 year warranty is something I am loathe to violate.

Bob

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Posted by rettop on Saturday, March 11, 2017 12:20 PM

Thanks for the comment. What an excellent idea. Makes one wonder why Walther's spec's or the turntable manufacturer/designer didn't incorporate this. Probably because of additional cost. I need to figure out, if possible, how to eliminate the gap. I think I have had the turntable a long enough time where warranty is no longer a consideration.

I use NCE DCC and since the turntable stopping points (tracks) are enabled to be controlled digitally thru the command controller, I'm wondering if the track selection couldn't be run thru a device like the NCE Mini Panel creating a macro to switch an auto-reverser to the outgoing track. I'd sure like to see your and other's comments on this.

Edit: This was meant for Mister Beasley.

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Posted by BMMECNYC on Saturday, March 11, 2017 12:27 PM

MisterBeasley
Can you bypass the split-rings somehow and just run the turntable bridge through and auto-reverser?

Im not sure if the ring arrangement of the power pick up will allow that.  A similar arrangement would have to be engineered to allow power to go to the rails (you cant just run a wire, because it will become twisted up).  I could take a look at mine at some point over the weekend to see if it is feasible.

Rule 108: In case of doubt or uncertainty, the safe course must be taken.
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Posted by rrinker on Saturday, March 11, 2017 1:18 PM

 It requires a little work because there are multiple contact rings on the turntable shaft (all the electronics and the motor are in the bridge) but I'm pretty sure I've seen someone post that they've done it.

                      --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by CSX Robert on Sunday, March 12, 2017 7:15 AM

rettop
I'm wondering if capacitors can be added to the turntable to eliminate this problem?

No, because the DCC power is AC.

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Posted by BMMECNYC on Sunday, March 12, 2017 8:30 AM

CSX Robert
 
rettop
I'm wondering if capacitors can be added to the turntable to eliminate this problem?

 

No, because the DCC power is AC.

 

 

Yeah, oops.

Any way.

As far as mods go...

There are 3 rings on the bottom of the Walthers 90' TT.  The outside split ring is track power.  It works by the fingers in the pit contacting the opposite sides of the ring.  The gap is the auto reverser.  There are 2 other rings and a center disk that all have fingers contacting them all the time.  Im not sure what these 3 items do, but if I had to guess, 2 are the motor and 1 is the auto indexing system?

The following statement is a WAG and I dont actually know if this will work, use at your own risk:

Remove all electronics from the TT.  Install the best motor decoder you can find (or maybe a sound one with air pump noises or electric motor sounds).  Hard wire the track power for the table into the table motor supply wires.  Use the same wires to provide power to the decoder then connect to the turntable motor.  Install a DCC Auto Reverser in line with the turntable's new power.

Remove all locomotives from layout. Program turntable on main.  Use your throttle to spin turntable (slow speed motor control very important).

This uses only 2 of the rings on the bottom.  You might be able to put some conductive paint across the other ring and use it for something else (lighting on the TT bridge or something).

The above is an untested theory.  I have not tried it to see if it is practical.  I provide no garuntee that this will actually work..  And it definitely voids the warranty.

 

Rule 108: In case of doubt or uncertainty, the safe course must be taken.
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Posted by Jacktal on Sunday, March 12, 2017 10:06 AM

If my memory serves me well,our friend Digital Griffin has initiated a post on this specific issue.It was then a nice exchange of knowledge that had brought an interesting solution to this problem.

I believe this post was about a year ago.If it can be found,it's a highly interesting read.

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Posted by Jacktal on Sunday, March 12, 2017 10:08 PM

I found it.It dates from last June,page 47:"Anyone ever consider putting an autoreverser on Walthers turntable".

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Posted by hon30critter on Sunday, March 12, 2017 10:20 PM

Here is a link to the thread Jacktal is referring to about connecting an auto reverser to a Walthers turntable:

http://cs.trains.com/mrr/f/744/t/247718.aspx

I think there may be a bit of confusion in the linked thread about which Walthers 90' turntable is being referred to. If I understand correctly, the factory assembled turntable is wired differently from the kit turntable. The factory assembled turntable apparently is the one with the split ring to which most of the posters in the thread are referring. I know from recent experience that the kit turntable does not have any split rings. One poster in the linked thread, Split Reduction, is apparently referring to the kit and is not aware of the differences between the two. With the kit, an auto reverser should be easy to hook up. Just use it to feed the bridge track. Am I correct or am I missing something?

I recognize that doesn't help the OP with his problem but I thought I should mention it so those of us with the kits don't get confused.

Dave

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Posted by rettop on Monday, March 13, 2017 1:55 PM

hon30critter

Here is a link to the thread Jacktal is referring to about connecting an auto reverser to a Walthers turntable:

http://cs.trains.com/mrr/f/744/t/247718.aspx

I think there may be a bit of confusion in the linked thread about which Walthers 90' turntable is being referred to. If I understand correctly, the factory assembled turntable is wired differently from the kit turntable. The factory assembled turntable apparently is the one with the split ring to which most of the posters in the thread are referring. I know from recent experience that the kit turntable does not have any split rings. One poster in the linked thread, Split Reduction, is apparently referring to the kit and is not aware of the differences between the two. With the kit, an auto reverser should be easy to hook up. Just use it to feed the bridge track. Am I correct or am I missing something?

I recognize that doesn't help the OP with his problem but I thought I should mention it so those of us with the kits don't get confused.

Dave

 

 
I followed the link and thank you for posting it. It is quite interesting but Mel's solution is beyond where I want to go. What an excellent job he did.
 
If you are refering to the Walther's turntables, I didn't realize they made a kit TT.
 
Thanks Dave.Big Smile
 
Robert
Tags: turntable , split ring , TT
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Posted by rettop on Monday, March 13, 2017 1:59 PM

Jacktal

I found it.It dates from last June,page 47:"Anyone ever consider putting an autoreverser on Walthers turntable".

 

 

Thank you sir (Jacktal). Have you done any more TT work?

Robert[quote user="Jacktal"]

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Posted by rettop on Monday, March 13, 2017 2:06 PM

BMMECNYC

"No, because the DCC power is AC."

 Yeah, oops.

The following statement is a WAG and I dont actually know if this will work, use at your own risk:

The above is an untested theory.  I have not tried it to see if it is practical.  I provide no garuntee that this will actually work..  And it definitely voids the warranty.

Yeah, double oops.

Are you really not letting me blame you when I destroy my turnable? 

Seriously, I really appreciate your input.

Robert

 

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Posted by rettop on Monday, March 13, 2017 2:18 PM

rrinker

 You can add keep alive capacitors to any decoder, it's just a matter of finding the right place to connect. Since the BLI decoders are somewhat more proprietary than others, this may not be quite so easy, but the basic circuit at a high level has to be similar to other decoders as far as having the bridge rectifier as the first thing in from the track pickups. There are likely existing capacitors designed to keep the sound system going, but the probably aren't big enough to clear the turntable gap. For a case like this, you don't really need a huge keep alive that also powers the motor, so it MAY be possible to increase the existing capacitors just to keep the sound on.

                             --Randy

 

Thank you for the input Randy. BTW, I did repower my Roundhouse ALGEIR w/ a NWSL truck drive. Took some milling of the frame and I changed it to an end door body. Attaching the original truck sideframes is problematic but I'm working on it.

Robert

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Posted by hon30critter on Monday, March 13, 2017 3:00 PM

rettop
If you are refering to the Walther's turntables, I didn't realize they made a kit TT.

The kits are the pits! Pun intended! They require a lot of TLC to get them to work properly. I built one not too long ago with some modifications to get it to perform decently. Here is the condensed thread:

http://cs.trains.com/mrr/f/88/t/261225.aspx

Note that the design of the kit turntable is different from the pre-assembled one so the above information won't do you a lot of good unless you rip your existing turntable to pieces or swap it for a kit version.

Dave

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Posted by Jacktal on Monday, March 13, 2017 4:03 PM

I've finally installed and used mine (N scale) and to me it's a jewel.Since it was designed so that it could be used for either DC or DCC,it has to control the track polarities mechanically,thus the two half circle slips (one for each track) and the gaps between,wich are the issue here.There's a dead spot every half rotation that can't be avoided.

I'm having the same issue and the only solution I can see is finding a small two paths slip ring that I could install on top of the middle arch structure.The slip ring assembly could then be held steady with a small tube (carrying the DCC) tied to an outer structure,like a shed that could also hide a reverser.However,finding a slip ring so small can be a problem.

May be doing this from under the TT is possible,but won't try it.The N scale version is so small,I fear I might just ruin it.

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Posted by rettop on Tuesday, March 14, 2017 11:22 AM

hon30critter

 The kits are the pits! Pun intended! They require a lot of TLC to get them to work properly. I built one not too long ago with some modifications to get it to perform decently. Here is the condensed thread:

http://cs.trains.com/mrr/f/88/t/261225.aspx

Note that the design of the kit turntable is different from the pre-assembled one so the above information won't do you a lot of good unless you rip your existing turntable to pieces or swap it for a kit version.

Dave

 

 
Dave- What a nice thread and pictures you created- both versions. You did a great job with the modifications. Thanks for sharing.
 
"The kits are the pits!" --wonderful.
 
Robert
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Posted by rettop on Tuesday, March 14, 2017 11:57 AM

Jacktal

I've finally installed and used mine (N scale) and to me it's a jewel.Since it was designed so that it could be used for either DC or DCC,it has to control the track polarities mechanically,thus the two half circle slips (one for each track) and the gaps between,wich are the issue here.There's a dead spot every half rotation that can't be avoided.

I'm having the same issue and the only solution I can see is finding a small two paths slip ring that I could install on top of the middle arch structure.The slip ring assembly could then be held steady with a small tube (carrying the DCC) tied to an outer structure,like a shed that could also hide a reverser.However,finding a slip ring so small can be a problem.

Maybe doing this from under the TT is possible,but won't try it.The N scale version is so small,I fear I might just ruin it.

 

 
If the wires from the two halves of the two slip rings are wired directly to the tracks and not through a digital controller on the bridge, then it would perhaps simplify the issue. The rings could be made continuous (whole) with a thin copper overlay on each and disconnecting the wires from one of the halves. An auto-reverser (AR) would of course be needed and that becomes a problem since I don't know of any that are small enough to fit on and under the bridge. To install the AR apart from the bridge would require another rotating connection for the bridge. Which brings me back to your solution of a slip ring on top of the bridge.
 
As I'm writing this I'm thinking modifications to the TT to fix the gap problem are all impratical. A different onboard controller from Walther's with a built in reverser and continuous rings is the ideal. Since Walther's has recently announced their new line of TT's I doubt it is a forthcoming design. Perhaps an aftermarket vendor could market a PCB replacement that worked?
 
I think the solution to the gap problem probably lies with onboard engine capacitors. As I stated elsewhere, this is not possible on BLI loco's without voiding the warranty. Unfortunately I think I must live with the problem. I value your input amd thanks for it.
 
Robert
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Posted by BMMECNYC on Tuesday, March 14, 2017 12:37 PM

If you made the split ring continuous, you would still need separate power to one of the rails, an auto reverser on the bridge would not solve this.  Also as described you would have an instantaneous dead short when you hooked this up. 

Rule 108: In case of doubt or uncertainty, the safe course must be taken.
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Posted by rettop on Tuesday, March 14, 2017 3:07 PM

BMMECNYC

If you made the split ring continuous, you would still need separate power to one of the rails, an auto reverser on the bridge would not solve this.  Also as described you would have an instantaneous dead short when you hooked this up. 

 

 
Sorry for the confusion- my bad. I meant to say the overlay to make the rings continuous would be two overlays- one for each ring & therefore each rail. I envision copper etched film.
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Posted by BMMECNYC on Tuesday, March 14, 2017 3:23 PM

rettop
 
BMMECNYC

If you made the split ring continuous, you would still need separate power to one of the rails, an auto reverser on the bridge would not solve this.  Also as described you would have an instantaneous dead short when you hooked this up. 

 

 

 
Sorry for the confusion- my bad. I meant to say the overlay to make the rings continuous would be two overlays- one for each ring & therefore each rail. I envision copper etched film.
 

Ah that makes more sense.

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Posted by CSX Robert on Tuesday, March 14, 2017 6:27 PM

rettop
...An auto-reverser (AR) would of course be needed and that becomes a problem since I don't know of any that are small enough to fit on and under the bridge. To install the AR apart from the bridge would require another rotating connection for the bridge...

Why would installing the auto-reverser away from the turntable require another set of contacts?  Unless I'm missing something, you could just have the output of the reverser feeding the turntable.

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Posted by rrinker on Tuesday, March 14, 2017 6:30 PM

That would not remove the gap. ANd with the reversing gap on the turnbtable, there's no need for an autoreverser anyway.

           --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by CSX Robert on Tuesday, March 14, 2017 7:50 PM

rrinker

That would not remove the gap. ANd with the reversing gap on the turnbtable, there's no need for an autoreverser anyway.

           --Randy 

I wasn't saying feeding the turntable with an autoreverser would eliminate the need for the gap, but if you did the other things rettop mentioned to eliminate the gap, then you could just feed the turntable with the autoreverser instead of having it on the bridge.

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Posted by rrinker on Wednesday, March 15, 2017 6:42 AM

 His initial post suggested just making the ring continuous - but you need TWO continuous rings to feed the track, which he corrected in a later post. With TWO continuous rings, then you just hook up an autoreverser to the wires feeding the rings.

 The putting it in the bridge idea came from the possibility that there was a power feed to the electronics that could be tapped off to power the bridge rails. In that case the autoreverser would need to be in the bridge because the drive electronics may not like the phase reversal.

                          --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by CSX Robert on Wednesday, March 15, 2017 7:29 AM

rrinker
With TWO continuous rings, then you just hook up an autoreverser to the wires feeding the rings.

Which is exctly what I was saying!

In his correction, he said he meant to say there would be two rings - referring to the same post where he said the autoreverser would need to be on the bridge.  I read that as meaning with two rings the autoreverser would need to be on the bridge, and was mearly stating that it would not.

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