Developing & Building Bell Code Block Instruments.

Discussion in 'Workshop Benches' started by gormo, Nov 22, 2020.

  1. gormo

    gormo Staff Member Administrator

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    G`day Folks,
    I ventured out into the shed very early this morning and kicked on for a while with the soldering on one of two of Little Bardfield`s block instruments. Bamford and Great Chesterford are complete.
    Various other chores had to be dealt with today as well, so they were taken care of as the heat of the day increased. At the moment, it`s not realistic or sensible to go outdoors, so I sit here writing my update in the cool of the air-con indoors.
    Testing on my first instrument connected temporarily to the railway revealed an issue I could not overcome with the wiring plan I had in place. The diode protection worked exactly as planned , however, the diodes were causing some resistance resulting in a voltage drop that was annoying me. In other words, when the locos would hit the isolated section fed through the diodes, they would slow by about 10 to 15%. No big deal really, but I knew it would nag away in the back of my mind and result in a re-wire at some stage in the future, so I removed the diodes and employed the capabilities of the rotating switch to activate and de-activate rail breaks as required. I have a plan of the new wiring system below. The little red and green bars depict the switch contacts settings.

    Block Instrument Commutator Settings.jpg

    In fact this system, not only allows the trains to run at the speed set by the controllers, but if I want to run my auto shuttle instead, all I have to do is set all instruments to "Train On Line".
    Train On Line closes all rail breaks and will allow the shuttle to run freely from Great Chesterford Junction on through Little Bardfield to Bamford where it will terminate temporarily before making a return journey automatically and so on.
    With the diode system there would have been a conflict with the shuttle and I would have had to switch off the block instruments completely........not that hard to do but a further complication.
    The re- wiring and removal of the diodes has resulted in a cleaner more efficient solution with sufficient protection built in and it still has that requirement for the station operators to co-operate to move trains between the three locations.

    So here we have Great Chesterford and Bamford complete and ready to be installed.

    DSC00682.JPG

    First Little Bardfield instrument being wired.........weather permitting.


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    You will notice on the back of the instruments we now have two terminals per rail to cover the rail breaks on the inner and outer rails of the isolated section.


    DSC00684.JPG

    I`ve been using a bench vise to hold the parts for certain stages of the wiring. I got this at Aldi a few years ago. It`s supposed to have a rubber sucker underneath to secure it to the bench........useless !!!!.....so I took the sucker off and screwed the vice to the bench.......beautiful....:thumbs:


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    You can set it at different angles and it will be handy for other modelling jobs as well. It has removable rubber inserts for the jaws which is good to gently hold those delicate parts.


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    This handle locks the rotating ball head in place.


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    I`ve also set up a proper connection for testing the boxes rather than using test leads and juggling wires. It`s a simple mono audio plug permanently set up and can just plug into the back of the boxes.


    DSC00689.JPG



    DSC00690.JPG

    These tools and jigs I am using, take some of the difficulty out of the build and they act like a second pair of hands sometimes.....:thumbs:

    Anyway that`s all I`ve got for you at the moment.........more as it happens
    :tophat:Gormo
     
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  2. Keith M

    Keith M Staff Member Moderator

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    I have one of the Aldi vices too Gormo, and as you say, the sucker mounting is useless and I never got around to looking at an alternative fixing method, in fact it's still in the box kicking around on the train room floor. My existing mini vice is the best part of 60 years old and has seen better days as the jaws don't always line up properly as it closes, so I shall modify the Aldi one and put it into use. Thanks for the nudge, it's a reminder to look it out and get it sorted.:thumbup:
    Keith.
     
  3. gormo

    gormo Staff Member Administrator

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    No worries Keith,
    I just removed the rubber and it`s lever system and put it aside. I then drilled three screw holes, one in each corner of the triangular base plate and fitted it securely to the bench.
    It`s not the best little vice ever made, but it`s good enough for those light jobs and the ability to swing it about into different positions is very helpful sometimes.
    :tophat:Gormo
     
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  4. gormo

    gormo Staff Member Administrator

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    OK Folks,
    Three down......one to go.

    DSC00691.JPG



    Work happens in fits and stabs determined by the weather and other commitments, but nonetheless, we are still moving forward. That`s the main thing.


    DSC00692.JPG

    My soldering is gaining speed with every instrument, so by the time I finish number four, I`ll be getting the hang of setting up these things.......maybe a little late but there you are....:scratchchin:
    All parts fitted on Little Bardfield instrument, including brackets and connecting plugs awaiting wiring.


    DSC00693.JPG


    Twenty, out of the twenty pins, will be used for each plug that connects the boxes so that they can communicate with each other.
    That sounds like a big task and physically it is. To connect these instruments, I will be running a substantial wiring system between each of the three stations plus links out to tracks outside the main room, plus providing a twelve volt power supply to each instrument.
    So lots of drilling access holes and crawling about on the floor and up under the baseboards.......physical Yes.....but mentally I`m on the down hill run cruising to the finish line. The only snag will be faults and fault finding, but at this stage I`m struggling to see where it can go wrong.......famous last words.:scratchchin:


    DSC00694.JPG

    So that`s the latest........more as it happens
    :tophat:Gormo
     
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  5. Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    What’s your plan for the outside plug and hiding it all? Is there a plug cover?
     
  6. gormo

    gormo Staff Member Administrator

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    G`day Andy,
    The plan, and you will see what I mean from the pics below, is to mount the boxes flush against the fascias on the front edge of my base boards.
    In order to do this, I need to create an access hole in the fascias big enough to be able to pass the plugs through from behind the fascia. Each instrument has three brackets to secure it to the fascia. One on top and two on the bottom.
    The access holes will allow the instruments to be fitted flush against the fascias.
    I intend to use some scrap 3mm MDF to do some testing with my hole saw to see just how big the holes will need to be, or if that doesn`t work out, I`ll resort to cutting a rectangular access hole just big enough to do the job........so the jury is still out on this one pending testing.

    Below we see the final front and back panels wired up and ready to be inserted into the second Little Bardfield block instrument.


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    All four block instruments completed

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    And now I am clamping them temporarily in their approximate positions to see how they will look when finally installed.
    First we have the Great Chesterford signal box instrument which transmits and receives to and from Little Bardfield, the first station up the branch line


    DSC00697.JPG

    Next we have the Little Bardfield signal box which has two instruments so it can receive and transmit either back to Great Chesterford signal box on the Main Line, or to Bamford signal box, the next and final station up the branch line.

    DSC00698.JPG

    And finally we have the Bamford signal box, situated at the end of the branch line and able to transmit and receive to and from Little Bardfield signal box.
    Bamford is nowhere near complete yet and needs major works, however this shelf area will be ideal for the block instrument. It can`t really go anywhere else because of the sliding fiddle yard to the right of it. I can set the instrument here wired up as a temporary fitting until I finally decide how the scenery is going to work here.


    DSC00699.JPG

    So that`s the instruments done and dusted.
    I guess I should continue on with this thread to cover the installation as well, for the sake of completeness .
    So once again.....more as it happens.
    :tophat:Gormo
     
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  7. Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    Well done. Love the lever frame. Gives me some ideas for our modified Hornby frame.

    anyway, reason for asking re the cables is I’m considering using a similar 25 way plug in the bottom of a picture frame to create a mimic display to hang on the wall above the layout. I’m just wondering best way for the cable running down ( so the frame can be unplugged and moved for work)

    should I find one, I’m thinking of using an old computer cable - printer? - to another plug under the layout where the other ends will terminate / run to the respective point motor.

    love the block instruments and look forward to seeing them working.

    Andy
     
  8. Keith M

    Keith M Staff Member Moderator

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    Try a length of plastic 'minitrunking' Andy, any alterations/additions, just unclip the lid, do what's required, then clip the lid back on again......neat and simple.
    Keith.
     
  9. gormo

    gormo Staff Member Administrator

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    G`day Andy,
    I think with Keith`s solution on the mini trunking, you could also hide the 25pin connector up in behind ,but within the picture frame, if the picture frame had sufficient depth.
    That would mean, to remove the picture frame from the wall for maintenance, you would remove the lid on the trunking as Keith said, then the picture frame could be removed away from the wall enough for you to unplug the concealed 25 pin connector in the back of the frame.
    I have seen some picture frames that try to give the impression of a box and they would be about 40mm deep.......might be worth seeing if you can find one over there in the UK.
    I will also insert a link below to a video which shows how the lever frames are done.

    :tophat:Gormo
     
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  10. gormo

    gormo Staff Member Administrator

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    G`day Folks,
    Well the Block Instruments are nice to look at but it`s no good just leaving them on the bench.......:scratchchin:
    I looked at how best to create an access hole for the plugs and wiring that come into the back of the instruments and settled on a rectangular hole.
    I felt the best way to accurately locate the instruments onto the fascias would be via a template, so I traced around an instrument and cut a template out of card. ( Thank you Mr. Kellog )
    On the template, I was then able to measure out and place the rectangle for the access hole and also the positions for screw holes.
    I decided to do the first instrument at Great Chesterford. I also changed my mind on where to locate it as my first option was not actually a good option. It would hang over the edge of my cassette storage drawer and also the location was exactly at the narrowest point in the room, so the instrument would be prone to getting knocked or damaged.
    So now it`s going into the space near GCJ yard where I used to hang my walk around controller and also there was a switch there for the layout lights. Fortunately the light switch had enough lead behind it to allow it to be moved across to the panel on the other side of the lever frame and the walk around controller now hangs over next to the turntable. ......Sorted....:thumbs:
    The template was used to draw the positions of everything onto the panel prior to cutting and drilling.

    DSC00707.JPG


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    You can see the pencil lines that tell you I`ve had two goes at this.......had to re-think the brackets on the bottom of the instrument......no big deal....I thought that could happen.


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    The instrument went on without much fuss and is anchored securely


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    And the all important access from behind


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    So I guess you could say that`s the hard one done and dusted. Not that it`s any harder to fit than any of the other instruments, but just the fact that it`s the first one and I`ve never done one before..........you`re always finding your way with these new things and I guess that`s good for me as I get older. I think it`s good to keep challenging yourself mentally and keep pushing yourself.....keep the grey matter working. That`s the great thing about this hobby.....there are many different facets to keep you stimulated.
    Time for a cuppa and a chill out.
    :tophat:Gormo
     
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  11. gormo

    gormo Staff Member Administrator

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    Two more fitted today at Little Bardfield
    Great Chesterford instrument is mounted to the right as trains from GCJ come from the the right, therefore Bamford is on the left because Bamford trains come from the left.
    Just keeping it logical all the way.....:thumbs:


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    :tophat:Gormo
     
  12. Gary

    Gary Wants more time for modelling.... Staff Member Administrator

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    They look good in position ! :thumbs::thumbs::thumbs:

    Cheers, Gary.
     
  13. gormo

    gormo Staff Member Administrator

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    Thanks Gary,
    Lucky last......

    DSC00712.JPG



    And a video update



    :tophat:Gormo
     
  14. Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    Interesting video! They look really good.
    I sit with my pop corn awaiting the “working” video :)
     
  15. gormo

    gormo Staff Member Administrator

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    Ah well Andy,
    You may have to wait a little while longer.
    I ran the first connecting cables between two instruments yesterday and I have an error.
    It seems that I have an extra feed to the LED`s keeping them on regardless of switch settings.
    Remember how I was confident everything would be OK and quoted " Famous last words " ......well they were famous last words.:facepalm:
    So at the moment all the instruments are removed and back on the bench and taken apart. I spent a good deal of yesterday afternoon back tracking through the wiring and fault finding. At first I could not see it, but eventually through the process of elimination, the little blighter revealed itself.
    Unfortunately my testing on the instruments during the build did not incorporate two instruments connected to each other for testing, so I moved forward with a false sense of security.
    I sorted two instruments out last night and have the other two to do today and then we try again.
    On a positive note......the first test connection at least had the bells ringing as they should, and the rather long connection cable was working as anticipated.
    I guess it would have been surprising if everything worked properly first go.........but not to worry.....everything can be fixed....:thumbs:
    :tophat:Gormo
     
  16. Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    Ah no. What was the issue? Diode? Faulty wiring? Or simply a crossed wire?
     
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  17. York Paul

    York Paul Staff Member Moderator

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    Excellent stuff Gormo and hope you resolve the fault. On the subject of lots of long lengths of wire I can see why the NSR Tyers one wire three position relays were used as a means of reducing cost on copper cable between block posts, they only needed one wire plus a ground earth as the commutator needle was shifted position the pulse frequency altered ... all clever stuff.
     
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  18. gormo

    gormo Staff Member Administrator

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    Well Andy, the biggest problem is the bloke who built them........:facepalm:
    There were two fundamental errors. The first was the LED OUT pins which were reversed on three instruments......should have been on the opposite bank of pins.....they were in the right location, just on the wrong side of the bank of pins.
    The second fundamental error, and also the most important one, was that the call switch LED that illuminates on top of the instruments.
    I had it powered from the instrument it was in. By doing that I was creating an extra feed back to the relay via the BUS connections, which powered the relay on all the time.....:faint:
    The solution was to redirect one of the LED wires in the receiving instrument so that it could be powered from the sending instrument. Two wires for the LED in the sending instrument were piggy backed off the green LED which lights when the call switch is on.
    Problems solved.........:thumbs:
    Both are working perfectly now as intended ,and all I have to do is copy my modifications over to the two remaining instruments.
    :tophat:Gormo
     
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  19. gormo

    gormo Staff Member Administrator

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    Yes Paul,
    You can use up a good deal of wire, in fact I have to go and get some more to finish the job. I am using 4 pair cable because it was given to me. The cable requires three lengths to do the job between instruments which leaves two pair spare. They may come in handy later on....who knows.?
    Anyway.....in for a penny...in for a pound..........it`s too late to step back now as the faults are fixed.
    :tophat:Gormo
     
  20. gormo

    gormo Staff Member Administrator

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    OK Folks,
    We are operational in the sense that two instruments can communicate with each other. All the instruments are tested and working perfectly. I just need to acquire some more cable to link the last two.
    For the moment, I can show you two instruments talking to each other. Bear in mind I still have to do the track connections as well, however that will be simple compared to what I have just completed.
    Anyway....a short video below.



    :tophat:Gormo
     
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