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Turntable Ring Gap Causes BLI Decoders to Stop

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  • Member since
    June, 2014
  • From: Southern New Mexico
  • 16 posts
Posted by rettop on Wednesday, March 15, 2017 2:35 PM

In regards to my post and the somewhat confusion about bridging the gap on BOTH track feed rings with ONE overlay- I did correct the so called error by saying you needed an overlay on each ring. However my original post said this: "The rings could be made continuous (whole) with a thin copper overlay on each and disconnecting the wires from one of the halves."

 
At any rate, I thought about this gap problem some last night. The third ring must be for the power feed to the bridge electronics as BMMECNYC pointed out. Since the gap extends to all three rings, either the electronics feed can handle polarity reversal or the wiring and/or the electronics compensates for it. I suspect the electronics do not care if polarity is reversed or the third ring would not be gapped.
 
To that end, if true, the AR could be elsewhere in the power feed to the TT itself and the ring gaps could be bridged by TWO overlays and disconnecting one side of the track feeds. I had previously connected an AR to the turntable feeds at installation (at the time not realizing what the gaps accomplished). Duh. There had not been any change in operation occuring. 
 
Now I have a question. Because of the existing gaps is the external AR doing anything?
 
If all of the above is true, than a solution to the gap cutout for sound decoders would be to use very thin copper sheet with two seperate but full circle rings on it. Then a piece of thin insulating film could be applied to one half of the two rings under the copper film. This would provide constant power to the track pickup on one side only and eliminate any wire cutting on the bridge feeds to the track. Yes????
 
Thanks to all who posted to this thread so far- it's great.
 
Robert
 
  • Member since
    February, 2002
  • From: Reading, PA
  • 22,073 posts
Posted by rrinker on Wednesday, March 15, 2017 3:27 PM

 With the gaps as they are, an external AR ould do nothing. There never is a short for the AR to detect and fix.

 Two thin continuous rings with insulation between them would work, but you may have to shift one of the bridge power contacts to make it touch one ring, while the other pickup would touch the second ring. You'd have to move one of the bridge track power wires to attach to the second ring. They both need to be continuous rings with no insulation on them for this to work - effectively wires right fromt eh bridge rails to the power supply - straight wires like that work, but if you constantly turn the table in one direction and never back they tend to get twisted up. Any insulation between a pair of rings has to be radially around the shaft. You can make the existing gap shorter as long as neither pickup can span both pieces (that would be a short) but I suspect it's already about as small a gap as can work reliably.

 I'm pretty sure the track feeds are JUST track feeds. They have nothign to do with powerign the bridge motor or electronics. You can stop the table at the dead spots and then move it again - if the bridge track pickups also fed power to the bridge electronics the whole thing would stop and get stuck at the gap area.

 This thread has more and more convinced me to not even bother with the Walthers built up turntable and instead just get something like the Diamond Scale kit or similar. I don't need indexing, I plan to have the turntable fairly up front where it will be easy to line by eye.

                       --Randy

 


Modeling the Reading Railroad in the 1950's

 

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

  • Member since
    November, 2013
  • From: Ledyard, CT
  • 1,554 posts
Posted by BMMECNYC on Friday, March 17, 2017 4:36 PM

rrinker

 With the gaps as they are, an external AR ould do nothing. There never is a short for the AR to detect and fix.

 Two thin continuous rings with insulation between them would work, but you may have to shift one of the bridge power contacts to make it touch one ring, while the other pickup would touch the second ring. You'd have to move one of the bridge track power wires to attach to the second ring. They both need to be continuous rings with no insulation on them for this to work - effectively wires right fromt eh bridge rails to the power supply - straight wires like that work, but if you constantly turn the table in one direction and never back they tend to get twisted up. Any insulation between a pair of rings has to be radially around the shaft. You can make the existing gap shorter as long as neither pickup can span both pieces (that would be a short) but I suspect it's already about as small a gap as can work reliably.

 I'm pretty sure the track feeds are JUST track feeds. They have nothign to do with powerign the bridge motor or electronics. You can stop the table at the dead spots and then move it again - if the bridge track pickups also fed power to the bridge electronics the whole thing would stop and get stuck at the gap area.

 This thread has more and more convinced me to not even bother with the Walthers built up turntable and instead just get something like the Diamond Scale kit or similar. I don't need indexing, I plan to have the turntable fairly up front where it will be easy to line by eye.

                       --Randy

 

 

If I could upload photos to photobucket I would post 8x10 color glossy photographs with circles and arrows and a paragraph on the back explaining what each one was.... wait thats from song.  Still though.  Any one else having problems with the bucket?

 

Rule 108: In case of doubt or uncertainty, the safe course must be taken.

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