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Offline marklin61  
#1 Posted : 20 July 2022 00:48:22(UTC)
marklin61


Joined: 05/01/2007(UTC)
Posts: 101
Location: Tuki Tuki Valley
Hi all,
Just seeking some helpful advice from anyone that has a good mechanical background on the Marklin 7286 Turntable.
I am having a problem with my newly installed 7286 Turntable using a TT-Dec decoder operated with my Win digipet software via my CS3.
After spending a great deal of time getting the decoder and the turntable to work I finally had everything running correctly .
This was at least until yesterday. Now I noticed that the turntable is having a problem turning. Initially I thought It was a decoder problem but now have ruled this out by using my backup with no change in condition. I removed the turntable bridge and inspected the motor assembly and noticed the throw bar located was quite stiff and wasn’t travelling correctly.. On further inspection (once removing the 4 screws) I noticed the small leaf spring was disengage and out of position. I reseated the small metal spring back in position, reassemble everything thinking my problems were over. Well they just started!!! Upon reinstalling the turntable deck I would test the function and on the first test everything worked correctly. The bridge would turn to the correct spoke track but the second attempt to turn the bridge to a different spoke resulted in just a clicking sound with no movement. So, I removed the deck and rechecked and the small leaf spring disengage again. Put back and retested with exactly the same result. I must of tested at least 10 times and every time the throw bar gets stiff and the leaf spring has come out of its little socket. I have even tried a replacement motor assembly thinking there might some manufacturing defect, but I get exactly the same result. So I have to assume I am doing something wrong. So anyone who’s is a mechanical genius that can point me in the right direction with be of some great use.
Photo of the leaf spring disengagement and correct position attached.
Many thanks
Steve534502C0-47F3-45CB-AD20-11FE6485A897.jpeg8B183D82-993B-4226-A132-7C990D41D3B7.jpeg
Steve...............

Life with Pinot Noir, Chocolate and Marklin trains..........
Offline owidgie  
#2 Posted : 20 July 2022 00:59:58(UTC)
owidgie

United States   
Joined: 03/06/2007(UTC)
Posts: 149
HI Steve, I would have to tear mine apart but the part at the motor shaft doesn't look correctly seated from the angle of the picture. I could be wrong and it might not have anything to do with it, but again, it might.

Rick

resource.jpg
Offline Dave Banks  
#3 Posted : 20 July 2022 01:07:15(UTC)
Dave Banks

Australia   
Joined: 08/03/2006(UTC)
Posts: 1,026
Location: Gold Coast, Australia.
[Try running it without any of the track inserts & see if this runs freely. I have taken one of these apart to see how it all works it can be fiddly.

Have a look at this: https://youtu.be/7Qz1jlGaeSs?t=424

Dave on the Gold Coast.
D.A.Banks
Offline marklin61  
#4 Posted : 20 July 2022 01:11:27(UTC)
marklin61


Joined: 05/01/2007(UTC)
Posts: 101
Location: Tuki Tuki Valley
Thanks Rick,
I did indeed check the motor seating. I think it must be a photo thing, but the motor is sitting flush in its compartment . I checked several times that every thing was in good order on reassembling. After replacing the spring back in position the throw bar will travel freely the way it supposed to be. It’s only during the second command ( as the first one works correctly) that the throw bar plays up. I’m thinking that the throw bar is pulling this spring out of its socket. But that only a guess.!
Steve...............

Life with Pinot Noir, Chocolate and Marklin trains..........
Offline owidgie  
#5 Posted : 20 July 2022 01:20:02(UTC)
owidgie

United States   
Joined: 03/06/2007(UTC)
Posts: 149
My guess is that the spring is coming out when the gear moves back the first time. When the gear moves forward into position the spring is already out of position and the unit doesn't work the second time. I guess it is possible that a small piece of the mount for the spring has broken off just enough to let it pop out. This may be difficult to fix if this is the case.

Rick

Offline Ross  
#6 Posted : 20 July 2022 04:54:17(UTC)
Ross

Australia   
Joined: 25/09/2006(UTC)
Posts: 868
Location: Sydney, NSW
Hi Steve/All,

Please read my Strange Bits Log Part 1 pages 9-12

I have had the TT jamming as you describe.

The other thing to check is that none of your spoke tracks are being pushed towards the centre of the TT this will cause the gear to become very tight on the pit rack gear and jam.

Hope it helps
Ross
Offline marklin61  
#7 Posted : 20 July 2022 06:11:44(UTC)
marklin61


Joined: 05/01/2007(UTC)
Posts: 101
Location: Tuki Tuki Valley
Thank you Ross, I have gone through the detail provided and there are some very good ideas to check. Great information and now I have some work to do when I return home.
One thing I did do was check the turntable with the hand lever which stepped through each of the 48 positions step by step. It seem to travel okay without catching any of the spoke rails ( which there are 14) I did put a bit of time in checking this when I first install the turntable. It was working flawlessly for the first week of testing. Is was just out of the blue that the turntable started to behave the way it is currently, totally with out explanation.
I have a old fleischmann 6652 ( bought for parts) Which now might just come in handy.
Steve...............

Life with Pinot Noir, Chocolate and Marklin trains..........
thanks 1 user liked this useful post by marklin61
Offline Ross  
#8 Posted : 20 July 2022 08:53:38(UTC)
Ross

Australia   
Joined: 25/09/2006(UTC)
Posts: 868
Location: Sydney, NSW
Hi Steve,

The hand lever test is ok but what you need to check is that the magnet that moves the hand lever moves the lever far enough to unlock the TT which also holds the contact closed so the motor can start.

Originally Posted by: marklin61 Go to Quoted Post
Thank you Ross, I have gone through the detail provided and there are some very good ideas to check. Great information and now I have some work to do when I return home.
One thing I did do was check the turntable with the hand lever which stepped through each of the 48 positions step by step. It seem to travel okay without catching any of the spoke rails ( which there are 14) I did put a bit of time in checking this when I first install the turntable. It was working flawlessly for the first week of testing. Is was just out of the blue that the turntable started to behave the way it is currently, totally with out explanation.
I have a old fleischmann 6652 ( bought for parts) Which now might just come in handy.


Ross
Offline Bigdaddynz  
#9 Posted : 20 July 2022 11:59:24(UTC)
Bigdaddynz

New Zealand   
Joined: 17/09/2006(UTC)
Posts: 18,661
Location: New Zealand
Thanks all, this will help with similar issues I have with the 7286 turntable.

Certainly some spoke rails do catch on the bridge and I have pulled the spoke fitting back and secure in place with a screw sitting in front of a rail tie. My only concern is with all the pulling and stretching is whether you end up distorting the turntable pit.
Offline JohnjeanB  
#10 Posted : 20 July 2022 13:06:21(UTC)
JohnjeanB

France   
Joined: 04/02/2011(UTC)
Posts: 3,084
Location: Paris, France
Hi Steve
Looking at your pictures, one thing is not correct
There is a rectangular spring that is not in its place.
Look here
Sans titre.png
It is supposed to be vertical and pushing against the main gearwheel
The other thing is the solenoid under the bridge does 2 things
- gets the motor started by closing a contact
- unlock the motor so that when the bridge reach its position, the motor is stopped instantly thus avoiding a "ballistic overrun" (bridge stopping too far.) The part circled in Rick's picture is the motor part to be locked when the spear (the long piece actuated by the solenoid) comes to rest.
Also, please don't be offended but your mechanism needs a good cleaning and only a very little lubrication.
Note: the 7286 Turntable is very silent and quite good but may become very bad when contacts are bent especially those at the end of the bridge.
Here is mine in operation. The noise you hear comes from a sound module

Sorry sorry for the things you know already. I hope you'l fix it fine.

Cheers
Jean
Offline JohnjeanB  
#11 Posted : 20 July 2022 13:32:15(UTC)
JohnjeanB

France   
Joined: 04/02/2011(UTC)
Posts: 3,084
Location: Paris, France
Originally Posted by: Bigdaddynz Go to Quoted Post
Certainly some spoke rails do catch on the bridge and I have pulled the spoke fitting back and secure in place with a screw sitting in front of a rail tie. My only concern is with all the pulling and stretching is whether you end up distorting the turntable pit.

Hi
This seems to indicate you have stress on your TT. A spoke rail is pushing towards the center or exerting a torque (spoke rail is not exactly along a spoke). The clearance between the bridge and the access track (spoke rails) is 1 mm and the altitude tolerance should be +/-0.3 mm or so.
Cheers
Jean
Offline marklin61  
#12 Posted : 21 July 2022 07:32:15(UTC)
marklin61


Joined: 05/01/2007(UTC)
Posts: 101
Location: Tuki Tuki Valley
Ross, I think you might be on the money here.I do remember the large gear every now and then felt like it had a small catch to it while I was inspecting its rotation. I will have to pull the whole mechanism apart and inspect the gears in more detail.

Unfortunately I’m on the road in the South Island and the whole country is in a sorry state with bad weather..so moving around is a real challenge, although you NSW folks would know what that is likeWink .
When I return home the turntable will be back on the inspection table for more analysis! Will report back once I have more information.
Steve...............

Life with Pinot Noir, Chocolate and Marklin trains..........
thanks 2 users liked this useful post by marklin61
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