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Offline PMPeter  
#51 Posted : 13 February 2018 00:59:00(UTC)
PMPeter

Canada   
Joined: 04/04/2013(UTC)
Posts: 1,273
Location: Port Moody, BC
Allowing the switch to float for me is a key. As I mentioned in a different thread a year or so ago regarding the problems with the attachable solenoids, screwing them down causes nothing but grief. They will work when you first install them, but may bind a day/week/month later due to temperature and humidity variations and the different expansions and contractions of the roadbed and the switch itself. The inconsistency had nothing to do with the microswitches since I always shorted them out. Removing the screws and letting the switch, motor and lantern float solved a lot of problems.

I do not use Merkur, but I assume it is similar to the Noch hard foam scenery pieces. I find these to also be quite temperature sensitive and it would be very interesting to see if the switch that is causing all of the grief on the Merkur would show the same symptoms if it was positioned on a flat piece of plywood as an experiment.
Offline applor  
#52 Posted : 15 February 2018 01:53:50(UTC)
applor

Australia   
Joined: 21/05/2004(UTC)
Posts: 1,653
Location: Brisbane, Queensland
Originally Posted by: DaleSchultz Go to Quoted Post
hmm I see. Does the servo perhaps actuate it slowly? The Märklin switch motors snap across and that may be the difference.

My k-track 'floats' somewhat in the Merkur, with no screws or nails holding it down other than the electrical wires. I have never had this problem.


servo actuation speed is adjustable. I do have it set relatively slowly to give a more realistic appearance.
I may have to try a faster speed on my other turnout that is sticky, since it moves most of the way but then stops just short of where it should - so a faster movement may fix that, if not ideal.
modelling era IIIa (1951-1955) Germany
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Offline applor  
#53 Posted : 06 March 2018 08:20:18(UTC)
applor

Australia   
Joined: 21/05/2004(UTC)
Posts: 1,653
Location: Brisbane, Queensland
Well I decided to bite the bullet and just replace the turnout that was not working with a new one.

Tested fine of course by itself and after installing the mechanism still worked great (yay so far)

After connecting the servo mechanism it still works great, it can operate all day:



Here's the kicker though - as soon as I connect the lantern mechanism it works OK for a number of operations before the servo tongue decides it wants to disconnect!



Cursing Cursing Cursing

Another afternoon spent that could otherwise have been spent elsewhere and the problem is not resolved.

I know the K track switches are very 'twitchy' and so checked the lantern and servo mechanism lever heights.
They should be fine servo height tongue is the same as all the others I have done.
My options are to either use this switch without lantern or take the servo side mounting apart and play with its height (ie. shave off some plastic) and see if I can get it to work reliably and rebuild.
modelling era IIIa (1951-1955) Germany
Offline hxmiesa  
#54 Posted : 06 March 2018 09:43:24(UTC)
hxmiesa

Spain   
Joined: 15/12/2005(UTC)
Posts: 3,519
Location: Spain
Thanks for sharing the videos.

I normally use Märklins own relays, and the snap-together tongues as you do.
But in a few places I use TILLIG under-floor servo motors, and I drive the switch directly; I place the motor with its actuator-arm just beneath the tongue of the switch, and drill a tiny hole in the plastic-band of the tongue of the switch, for the vertical actuator-arm to move the switch directly; No posibility for mechanical disconection!

The actuator-arm is like a thick piano wire, and can flex a little bit, so if I have a troublesome lantern, it might fail too, like in your case. -But at least it woulnt disconnect mechanically.
Best regards
Henrik Hoexbroe ("The Dane In Spain")
http://hoexbroe.tripod.com
Offline PMPeter  
#55 Posted : 06 March 2018 15:14:24(UTC)
PMPeter

Canada   
Joined: 04/04/2013(UTC)
Posts: 1,273
Location: Port Moody, BC
Originally Posted by: applor Go to Quoted Post

I know the K track switches are very 'twitchy' and so checked the lantern and servo mechanism lever heights.
They should be fine servo height tongue is the same as all the others I have done.
My options are to either use this switch without lantern or take the servo side mounting apart and play with its height (ie. shave off some plastic) and see if I can get it to work reliably and rebuild.


I had a similar problem with one of my switches after converting it to servo control. It was the lantern that caused the issue. The tongue seemed to engage but it obviously didn't. I ended up taking the lantern cover off and manually pushing the lantern tongue in until I heard the click. I then painstakingly reassembled the lantern around the properly connected tongue and I have had no problem since. I also do the same with the tongues for the servos. If I don't feel the click I remove and reinsert until I know I have a positive connection.

It is pretty finicky work and all I can assume is that the tongues sometimes only partially engage either high or low and then cause binding. It's hard to tell when you can't see inside.

Peter

thanks 3 users liked this useful post by PMPeter
Offline applor  
#56 Posted : 08 March 2018 04:45:12(UTC)
applor

Australia   
Joined: 21/05/2004(UTC)
Posts: 1,653
Location: Brisbane, Queensland
Originally Posted by: hxmiesa Go to Quoted Post
Thanks for sharing the videos.

I normally use Märklins own relays, and the snap-together tongues as you do.
But in a few places I use TILLIG under-floor servo motors, and I drive the switch directly; I place the motor with its actuator-arm just beneath the tongue of the switch, and drill a tiny hole in the plastic-band of the tongue of the switch, for the vertical actuator-arm to move the switch directly; No posibility for mechanical disconection!

The actuator-arm is like a thick piano wire, and can flex a little bit, so if I have a troublesome lantern, it might fail too, like in your case. -But at least it woulnt disconnect mechanically.


Yes that is how the other manufacturers do it - directly connecting the servo wire to the tongue drawbar and that way there are no mechanism issues.
Marklins design however is to allow the switch to be run in reverse without causing derailments. Usefull but sometimes you wonder if its worth the troubles.
Had I to start again I would strongly consider using Tilig or Peco 2 rail with the centre stud strips you can buy. I didn't realise that was an option when I first started.

In any case, back to the problem at hand. The good part is that this issue is easier to solve than the previous one (where the mechanism moves but the tongue doesn't)
I removed the servo and anything else that could possibly interfere with the mechanism. This did not help and I struggled to get the tongue piece to lock into the mechanism at all.
So out comes the turnout, had a play and then on closer inspection I found that one of the plastic connector tabs at the end of the turnout was actually bent upwards.
This resulted in a slight increase in distance between the plastic body and the metal plate it sits on. It would have happened when installing this turnout due to the tricky positioning.

photo of the tab but on a new turnout.

tab issue.JPG

This increased the gap in the slot further down that the tongue piece slots into, making it far more likely for the tongue piece to lose lock due to being too high or low.

I bent the plastic tab back down flat and spent time carefully applying pressure to the metal body with the plastic body to remove any possible gap/space.

Switch was re-installed and after a bit of re-assembling and pressure here and there it is all working again.


modelling era IIIa (1951-1955) Germany
thanks 3 users liked this useful post by applor
Offline hxmiesa  
#57 Posted : 08 March 2018 09:08:24(UTC)
hxmiesa

Spain   
Joined: 15/12/2005(UTC)
Posts: 3,519
Location: Spain
Originally Posted by: applor Go to Quoted Post
Yes that is how the other manufacturers do it - directly connecting the servo wire to the tongue drawbar and that way there are no mechanism issues.
Marklins design however is to allow the switch to be run in reverse without causing derailments. Usefull but sometimes you wonder if its worth the troubles.

The aproximatly 30mm of stiff piano-wire allows the frog to be run up in reverse direction, so no problem there. The Tillig motor occupies an enormous lot of space beneath the plate, so possible issues here if you run a dense multi-level layout...

Quote:
So out comes the turnout, had a play and then on closer inspection I found that one of the plastic connector tabs at the end of the turnout was actually bent upwards.
This resulted in a slight increase in distance between the plastic body and the metal plate it sits on. It would have happened when installing this turnout due to the tricky positioning.

I know this problem too!
Now that you have documented it well here, we can all avoid it in the future! So thanks for sharing, again.

Glad that you solved your problem!
Best regards
Henrik Hoexbroe ("The Dane In Spain")
http://hoexbroe.tripod.com
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