Go_West Posted September 11, 2016 Author Share Posted September 11, 2016 The idea was to mount the safety valve under the supper heater so a Hornby part was dismantled and re machined smaller all over the body was reduced in length and width the stainless steel valve had its stem shortened the valve nut had 1.5 mm taken off one end and the body also has the barrel reduced one end to take the take off pipe to the Bodies safety valve location./media/tinymce_upload/dffe9aace85a0516167e0685e900d358.jpgIn the picture here you can see from left to right the safety valve body then the valve with its rubber seat next the valve spring then the nut and last the cover and pipe to take away the steam to the bodies safety valve we hope./media/tinymce_upload/65abfe340b97730051e694b90d90f5cc.jpgThis picture has the supper heater changes first on the left is the long pipe from the tender to the base of the safety valve next is a gasket then the take off pipe and fitting to the supper heater then a second gasket last the fixing screw./media/tinymce_upload/e64c28605b422e282a1aea9fbccd1e89.jpgHere you see the valve in place with rather a long pipe to the bodies safety valve and at the back end on the right is the pipe to the tender not sure how this will work but one thing that’s going to be a problem is the linkage from the servo motor to the regulator as the new position for this valve has used up its space./media/tinymce_upload/64f8ea4c970703a802ca5489ebdf9228.jpgOn the other side of the engine things are looking a bit full of pipes and whistles but will try to over come these problems. Will be away for a few days looking at big steam engines and the like so may go a bit quite here. Link to comment Share on other sites More sharing options...
Go_West Posted September 19, 2016 Author Share Posted September 19, 2016 Well had a break and now looking once more at the S69 trying to remember what was we doing so went through all the forum pages just to recap and its amazing how much from the drawings and pictures things have changed.One of the places we went to was the Dean Forest Railway and the tank engine here was in service and on a warm sunny day the cab of this engine is not the best place to be.Looking at this engine and seeing it working made me think of the next project maybe? have started looking and buying bits already but hold on we still have a way to go with the S69 so lets have a look at the electronics and what we need to make./media/tinymce_upload/2bac22d941da598b9035d8334b20697e.jpgWhat i like about the Hornby electronics is it works and is small and simple. Many have tried and failed to make a better system of control but in time as electronics get ever smaller and better who knowsElectronics dont like too much heat and water and in a steam engine we have both so thought on where and how the electronics fit is a must, so on with the work lets start with the Hornby system and see what it does.How it worksThe motor which move’s the combined regulator and whistle steam valve is driven by a simple circuit which has a relay at its heart. This relay has its contacts wired in the normally closed position so that when the full voltage of 16 volts is supplied to the track the circuit through the bridge rectifier and smoothing capacitor feeds a transistor which on seeing the higher voltage conducts making the relay pull in and opening its contacts switching the motor off.Now moving the regulator lever on the train controller to the right sends a 50% reduction in the power to the track of 8 volts this action also determines which way the motor will turn by polarity + - to the track and then to the small PCB relay this much reduced voltage turns off TR1 and the relay drops out causing this 8 volts to be passed through the relay contacts to the motor making it move the regulator/whistle.When the lever is released the full 16 volts returns to the track and the base of TR1 which goes high and conducts so that the relay pulls in the contacts open the motor stops turning. Moving the lever to the left will reduce the voltage as before but will change the polarity - + to the track and the motor will turn in the opposite direction.To here you see the Hornby control print board and below the circuit./media/tinymce_upload/ea3f938fd2d03bfad42658ba2cdcb3d0.jpg/media/tinymce_upload/4fdfd25a8900fc119daabddee1746d1d.jpg/media/tinymce_upload/04c5ab5b0bebc43b3f4afd5c62d4f7c9.jpg Link to comment Share on other sites More sharing options...
96RAF Posted September 20, 2016 Share Posted September 20, 2016 That voltage shift explains exactly why you cant mix live steam and DCC on the same track Link to comment Share on other sites More sharing options...
Go_West Posted September 20, 2016 Author Share Posted September 20, 2016 What is needed for this engine like others I have built is some thing as small as we can get so that it takes up as little room as possible.The largest component on the Hornby control PCB (printed circuit board) is the relay and by replacing this with a SSR (solid state relay) a much smaller control board can be built.Looking at the 2 components here you have the Hornby relay and the SSR and a 2p coin./media/tinymce_upload/2b505ca4cb3319ce3f122858bbf130df.jpgWe are hoping that this SSR will do the trick but as yet untested so we need to built the rest of the circuit to drive this small device which is below Fig 2./media/tinymce_upload/112ce9fe01a492a88cc149f56858b1af.jpgNext is the PCB drawing which we will mount the components on as smd they are very small and when ever I start this more bits end up on the floor than on the circuit board. The circuit board was drawn up on the PC and printed on clear plastic sheet on an inkjet printer so that you end up with a negative. The board has a photo film printed on the copper side of the board and then it developed leaving the same image as the film behind. Once inspected for faults the board id put in a tank of ferric chloride for 15 to 20 minutes and out comes your PCB we hope./media/tinymce_upload/5c7844bcdbf1a099d0251890ce5f1c48.jpg Link to comment Share on other sites More sharing options...
Go_West Posted September 20, 2016 Author Share Posted September 20, 2016 Just had a thought thinking about this engine’s electronic a new idea for the electronic control PCB came to mind and its so obvious it reduces the number of components and therefore the size of the PCB and this is to use the Hornby design but removing the relay for the new SSR as below Fig 3./media/tinymce_upload/df30c740fbf6edd383cbf345664c9586.jpgHow it WorksThis will work in a similar way to the relay idea but the SSR will not switch on as long as the pos side of the SSR is held to 0 volts. As the track volts drop to 8 volts the transistor will switch off and the resistor 2k2 R3 will take over and power up the SSR so that it will conduct and the motor will turn.Will build this latest design and report back Link to comment Share on other sites More sharing options...
96RAF Posted September 21, 2016 Share Posted September 21, 2016 Its amazing that you can build such a circuit on a pcb the size of a mobile phone number key. Well beyond my eyes and finger skills. No doubt it could all go on a single custom chip given there was a demand for a million or so. Keep at it Ken, every day takes this engine closer to the rails.Rob Link to comment Share on other sites More sharing options...
Go_West Posted September 21, 2016 Author Share Posted September 21, 2016 Hi RobAs you say things are always moving on and this makes for micro electronics that is for ever getting smaller and smaller when I started work it was all valves thats them glass things like light bulbs for those that are born after 1960 When the transistor took over but I think having said that hi fi people like valve amps and are making a come back so as they say what goes around comes around As a X RAF man in my work shop is a 1940 TX1198 or is it 1196 I think is the model pilots transmitter which still works but no one to talk to on the frequency that it operates on.just looked up on the web its tx1196 Link to comment Share on other sites More sharing options...
96RAF Posted September 21, 2016 Share Posted September 21, 2016 The only one I can remember Ken is PTR175 from the days when they were the latest and greatest aircraft V/UHF radio fit, complete with UA60 control box. I was happy fixing TVs when they had valves (had a big box of them pulled from duff tellys) but nowadays they are like cars - white man's magic. The last modern electronic device I mended was a Sony Beta recorder. Link to comment Share on other sites More sharing options...
Go_West Posted September 22, 2016 Author Share Posted September 22, 2016 I think they may be a bit newer than this set as it's just a VHF set as for tv fixing I think I still have some pcl86 valves some place and ecc88 you never know they might come back. Link to comment Share on other sites More sharing options...
Fishmanoz Posted September 22, 2016 Share Posted September 22, 2016 Those were the days, valve jockeying, all you needed was a little common sense. I used to steer well clear of the EHT section though, although if the EHT output valve was glowing bright blue, you could replace that just like any other. The transformer, another matter, get the TV techo in. Link to comment Share on other sites More sharing options...
Go_West Posted September 23, 2016 Author Share Posted September 23, 2016 Hi fishmanozIs this turning into na old gits forum talking about times long gone as a teenager I was building a 27mhz radio control using a single valve for the TX and transistors for the RX so there I was power on and working near my bedroom window trying to tune in the TX a man in at the bottom of his garden shouting to his wife "must be someone using an electric drill" I nipped down stairs and turned on the TVs and the screen had about 4 black lines about an inch wide across the screen. It was my TX that was jamming his tv so switche'd it off and the picture was fine. Link to comment Share on other sites More sharing options...
pidder Posted September 24, 2016 Share Posted September 24, 2016 Talking about long ago, I seem to recall the TR1196, weren't they used in the GCA training Oxfords at Watton? Happy days... Link to comment Share on other sites More sharing options...
Go_West Posted September 24, 2016 Author Share Posted September 24, 2016 Re pidderThe area that you are in with the TR1196 Is regarding its use in training I know nothing but sounds interesting as many that used or worked these transmitters are raiding away like so many things today I was speaking to a chap that repares railway engines and the like and was saying that not many of the youngest this days are interested in the old ways of engineering and feels that the level of skilled people is dropping in lots of fields. Link to comment Share on other sites More sharing options...
pidder Posted September 25, 2016 Share Posted September 25, 2016 Just to prolong it a bit, I spent a lot of time in 1950 in the WT workshop at Watton, servicing these tranceivers. Found ou recently that the Airspeed Oxfords that they were fitted in originated from Neville Shute's company, Airspeed. His "Slide Rule" makes very interesting reading. Link to comment Share on other sites More sharing options...
Go_West Posted September 25, 2016 Author Share Posted September 25, 2016 piddernot wishing to drag this out as some might think what the hell these people are on about and when are we going to see more live steam stuff here is a picture of the thing in question a pilots TX RX it had a 3 push button switch so you could select the following i think..... ground to air. air to air. and distress. but some one might put me right on that all fix by crystals is that almost right pidder? the one bit thats missing is the 24 volt rotary transformer but can be powered up with a standard transformer. /media/tinymce_upload/b536a2441033d5919c8a67f45efeeb08.jpg Link to comment Share on other sites More sharing options...
pidder Posted September 26, 2016 Share Posted September 26, 2016 gowest, I'm pondering on the picture of the control panel you showed, all I can recall is a small vertical metal box with four pushbuttons to change channel, each crystal controlled as you say. Perhaps this was a special arrangement installed in the WT workshop.Think I only ever did one aircraft service, don't remember any details.It's a good job I'm messing about on your thread, not someone else's, following it with interest, almost sold on trying live steam! Link to comment Share on other sites More sharing options...
Go_West Posted September 26, 2016 Author Share Posted September 26, 2016 /media/tinymce_upload/b536a2441033d5919c8a67f45efeeb08.jpgHi pidder the box with the red light is the transmitter next to the red light is a square small cover where the crystal went and above that is the receiver which has the same cover with the next set of crystals the left hand end has the areal and Earth connections and the other side not pictured has the 24 volt input and the lead to ear phones and mic plus the push button switches. Link to comment Share on other sites More sharing options...
Go_West Posted September 26, 2016 Author Share Posted September 26, 2016 lets get back to the engines electronicsthis is what we hope is the final design of the printed board/media/tinymce_upload/7f5ff9fe3c03595bf8ea65b38335cf6c.jpgwhat i should have done is try out the circuit on a PC test program or build it and see what happens rather than go in to production but i can always change parts if it dont work and as it just a few parts not a real problem./media/tinymce_upload/1d8f958c63432745358a211923d0bf11.jpgthe picture above is of the components in position on the paper print out the resistors are the red marks on the paper all the other parts look ok so will go ahead and make the board./media/tinymce_upload/d2fe9e1ebaaa86485e0a998099e1f7d3.jpgThis is a drawing of what we want the PCB to look like when finished./media/tinymce_upload/22127a8baa2bb99ffa157f44dc2680a0.jpghere are 6 of the drawings printed on clear plastic so we have a negative to print from and having 6 PCB's a few spare ones should something go wrong./media/tinymce_upload/0f7186e7921c549c6b174ceb6b097e05.jpglast is the printerd board which as you seehere has a white plastic film to protect it from the light till we are ready to use it. Link to comment Share on other sites More sharing options...
96RAF Posted September 27, 2016 Share Posted September 27, 2016 Where do you think it will fit Ken.Presumably it needs to be away from too much heat and steam oil.Do you have to protect it say with varnish, potting or a sleeve?Rob Link to comment Share on other sites More sharing options...
Go_West Posted September 27, 2016 Author Share Posted September 27, 2016 RAF96yes as you say different ways to keep it dry as for the heat I am hoping that a small area under the cab floor is the best place for the PCB and also the main power connections have not far to go to reach the tender and when the wiring is run this way they look like the water and air connections on the full size engines. Link to comment Share on other sites More sharing options...
96RAF Posted September 27, 2016 Share Posted September 27, 2016 Another option is once the board is proven and all wires connected, etc is to encapsulate it in Araldite. I used to bomb proof my rewound slot car motor armatures by warming them up to thin the epoxy and it would run nicely into the windings. Just a dip into runny Araldite could work For a pcb. Link to comment Share on other sites More sharing options...
Go_West Posted September 27, 2016 Author Share Posted September 27, 2016 yes RAF 69that is a good idea and have used it before so might well do that Link to comment Share on other sites More sharing options...
Go_West Posted September 27, 2016 Author Share Posted September 27, 2016 Making a Printed BoardSo we have our film next is to cut some board the same size or a fraction larger than the negative and place the negative the right side up in the ultraviolet light box./media/tinymce_upload/f02606f4b810526230e417887deb472e.jpgNow it time to remove the protective plastic film from the light sensitive side of the PCB /media/tinymce_upload/2b4f583cdb656b732ddcc7a927af2e70.jpgPlace the PCB on top of the negative film then I put some bubble wrap on top and switch on the light and close the lid of the light box this keeps the film in good contact with the board./media/tinymce_upload/2463baa683128394f0bff91386f29c83.jpg/media/tinymce_upload/813cd2d999326956adcc4c3d69b9e5bb.jpgSet the timer for 2 minutes 30 seconds for the exposure time and wait./media/tinymce_upload/fb890228639703398f570acf982ce6aa.jpgWhen the timers ends take out the PCB from the light box and put it in the developer only a small amount of developer is needed and an ice cream container comes in useful. After a few minutes you see the out line come into sight and what we have is a printed board with an area of copper showing and other parts of the board still covered in the green film. /media/tinymce_upload/e8cd2c44f1478cee2d3468881bddb065.jpgThis means that when we put the board into the ferric chloride the exposed copper will get eaten away leaving just the green areas under which hides our copper track of our Circuit./media/tinymce_upload/f29ec88344c151c27848de5791dda38a.jpgI have an air pump to bubble the ferric chloride which speeds up the etch process so all I need to do is place the PCB in the basket container and lower it into the ferric chloride. This may take 20 minutes for the board to be completed./media/tinymce_upload/25fca1c00441f74a832ce825ca4d108b.jpg Link to comment Share on other sites More sharing options...
Go_West Posted September 27, 2016 Author Share Posted September 27, 2016 Now we have 6 printed boards one in the bottom right hand corner looks as if it has not come out right but that’s why its best to do more than one on a sheet as we are in the shed type work shop.Cut up the boards to size and clean off the protective coating from the copper surface./media/tinymce_upload/7f268cd28d34c569ce259958346f466d.jpgThe 20 p give you an idea as to how small this control board is and here it is with the copper showing after removing the film, next to tin the copper tracks with a soldering iron so that the components are easier to solder on./media/tinymce_upload/81f28a7030eae10435283383d0b7fe79.jpg/media/tinymce_upload/6af9e7ddd534a98d7ae6c11449016b2f.jpg/media/tinymce_upload/8fc12d27d47fea8444ff1227b50a7fcf.jpgSoldering the components on is a bit of a game but I got there in the end./media/tinymce_upload/25dd1441486af7f99a62ae993deae78a.jpgNow we had a finished printed board and that’s how its done. Does it work we will find out next and see if not only the design is right but if this very small SSR can have the power to drive the Hornby electric motor?More to come Link to comment Share on other sites More sharing options...
Go_West Posted September 27, 2016 Author Share Posted September 27, 2016 Looking now at the finished printed board can it be made even smaller? but before i start to change it I must find out if it works. Link to comment Share on other sites More sharing options...
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