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  1. TCSC47

    Selenium rectifier?

    Thanks for these publications DP. Re - lack of caboose. As you no doubt know, present day trains don't have cabooses. As I am a lad from the 50's this always looks WRONG to me so if I could make a law, it would be that all freight trains must have a caboose, even if they are not needed.
  2. TCSC47

    Alternative to a bad tachometer filter?

    For me the most likely cause of the problem could be a broken wire or corroded connection, so check that there is continuity between the tacho signal source and the tacho. But certainly a simple circuit that is not safety critical and you could make yourself. The components are pennies.
  3. TCSC47

    Turn On and Off a Smaller Voltage from a Larger One

    Hi Madaxe I'm not sure exactly what you want to do, but if I have it right, I would suggest just a simple mechanical relay as in the attached cct. diagram. I have had a look at your other post here and you say you don't have an electronics background, so I am not being condescending to suggest...
  4. TCSC47

    Selenium rectifier?

    I hadn't thought of that.
  5. TCSC47

    Selenium rectifier?

    I think I have just realised why there are two negative pins. It is due to the way the selenium rectifier is manufactured as layers forming four diodes. There will always be two diodes on the outside that have to connect to each other hence the two -ve have to link up over the outside. Normally...
  6. TCSC47

    Selenium rectifier?

    Cheers. There is a lot written on Hammant and Morgan controllers available from the 1950's to 1970's in the UK model train forums and blogs, mainly I think because of nostalgia. The fact that so many are still around speaks to their toughness and uniqueness. I haven't yet found anything about...
  7. TCSC47

    Selenium rectifier?

    Apologies, I did not mean to sound argumentative. I was commenting on the 1950's design as I found it. Your comments are quite valid and pretty much the same as the ones I pondered upon. I think the answers are mainly that the design was governed by 1950's available technology. A modern train...
  8. TCSC47

    Selenium rectifier?

    And again, no need for the resistor you mentioned, See my comment on the resistor above. possibly a smoothing electrolytic capacitor across the output, approx 1000uF per amp. The controller was designed for model train control in he 1950's and way back then a 1000uF cap would have been rather...
  9. TCSC47

    Selenium rectifier?

    It is not too obvious from my picture, but enlarge the picture of the component and look carefully at the -ve tabs. I haven't pictured it from the best angle but you should be able to see one tab behind the other one. The two -ve terminals are an interesting point. The function they serve in...
  10. TCSC47

    Selenium rectifier?

    Hi Everybody I have been trying to find the data sheet and any details available of what I believe to be a selenium bridge rectifier. The component came out of a model train controller I bought way back in 1962 (How time flies!!) here in the UK. The controller was made by Hammant and Morgan who...
  11. TCSC47

    My subwoofer is making a thundering noise, can anyone help?

    I've come to this late, so have people either given up or has the problem been solved? I have had a quick look at the answers so far and I might have missed somebody giving the most obvious answer. The subwoofer is designed to work from a 12V car battery so the first thing to do to problem solve...
  12. TCSC47

    Cable Connectors

    Just been looking at bertus hardwarebook.info/ and it looks very useful. Cheers bertus. Also I agree with Martaine about building up your own data book. I have a number of Word files of info I have cut and pasted from the interweb and they have proved very useful over time. Once upon a time...
  13. TCSC47

    Can anyone explain how this battery charger works?

    In the diagram the yellow disc component has been assumed to be a capacitor. However, as you say the circuit would not work if it was. The yellow disc has to be something else like a thermal fuse, or a current limiting device of some sort. I am writing this late at night and I am too tired to...
  14. TCSC47

    Anyone know what this is?

    What are you going to do with it? There appears to be only a two wire connection. Put a push button across the wires and see if you can get it to count up.
  15. TCSC47

    MC1709

    The datasheet ( https://pdf1.alldatasheet.com/datasheet-pdf/view/130010/MOTOROLA/MC1709.html looks pretty much like a generic 709. Compare with https://pdf1.alldatasheet.com/datasheet-pdf/view/9015/NSC/LM709.html They are priced at $20 plus!!? Ridiculous for such a genuine museum piece...
  16. TCSC47

    Anyone know what this is?

    It certainly looks very similar to bertus' exercise bike reference. I've got one very like it on my step exerciser but the fact that the device shown here logs distance rather than steps as mine does, probably says it is not a step exerciser. How I think it works. Work done (energy in calories...
  17. TCSC47

    Book Reviews

    I love these old electronics data books. I remember as a wee lad pouring over books like this trying to understand what they were on about. Then when I started training back in the 60's, feeling very chuffed with myself when I actually used them to design something. Sadly for my nostalgic self...
  18. TCSC47

    Which speakers are best for home?

    This string on speakers with its reference to a new house build gives me an in into one of my "almost famous" stories. I was lucky to do my electronics apprenticeship at a government research establishment here in the UK, The Royal Radar Establishment, Malvern, where a lot of famous names worked...
  19. TCSC47

    Best op-amp for audio use?

    A very detailed book. Cheers B Not only that but with several very interesting looking web references at the end.
  20. TCSC47

    Which speakers are best for home?

    If some here wondered at my term, DAB I have just seen that they don't use it in the USA. Basically in the UK it is digital broadcasting on frequencies around 500MHz or so and has become as popular as FM around 100MHz or maybe even more so...
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