Not bored with the Boards.

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  • No 1 again on dowelsjoystick%20extenders%20005_zps0vvfksnv.jpg
  • Includes the thermal fusejoystick%20extenders%20002_zpsf1fu8e5r.jpg
  • No 1 again . Manufacturer's ID at bottom?joystick%20extenders%20001_zps07jix1ea.jpg
  • A close up of the widingsjoystick%20extenders%20004_zpsdnh45be7.jpg
  • But which is the primary? The one with the thick wires I assume! Mark has mentioned the enamel insulation on these windings.

  • i suppose I could make into a kind of non working "power supply exhibit" with transparent sides!
  • An enclosure for itpower%20supply%20enclosure%20001%202_zpszlozlsoh.jpg

  • Re above pic.

    Inside an old HP printer I found a "power supply enclosure" which is big enough for this . It is not a loose fit but not too tight either : it is "just right" to slide in : only one side of it needs blocking off to secure it safely .So the next job will be to solder in 4 cables making a note of which coil and side they are from . Then I need to compare with a working power supply . I can do that while I rust treat them (multi-tasking!).

    I have given up getting an enclosure with the size efficiency of the original design but it may yet work in a much bigger enclosure .
  • Re above pic

    I think an eraser glued in at the bottom and a cable tie ( going from side to side using holes drilled in the enclosure's side edges), across the top would secure it in the enclosure box
  • Back to No 3 (the yellow capacitor power supply)

    I found out what made the buzz . It is all to do with the way the metal plates are fixed together : some have a thin "stripe weld" running across a few millimetres of the edge of the plates whereas others are fixed loosely or have bolts . This one with the yellow cap had holes for bolts with nuts but these had not been used : it was a though they were confident that the block of plates would hold together without them . I tried putting just one bolt and nut on and it stopped the buzz : so it was not the capacitor that was buzzing . I think the buzz was caused by the loose plates vibrating against each other.on removal I could see that the yellow cap was labelled on the bottom end as FRAKO 4700/16 57+.

    I think that generally with these power supplies the mains input cables go to the winding with THIN wired coil not to the THICK wired coil that I had thought previously

  • Different approaches to Space and Time

    Power Supply No 5 had been repaired quickly 30 years ago with Araldite and it had fitted back easily into a standard size case. It had been found to work OK some 30 years later . The downside with this approach is that it cannot be easily taken apart and reworked , the Araldite used prolifically to hold it all together had "seen" to that. But it was not a bad as a "quick fix"

    The opposite approach is being used on the No 1 power supply (broken and in bits) . Considerations of effective use of space and time have been cast asunder . It cannot be fitted into a small hobby box , so "what the heck" I might as well indulge it to the full by using ceramic blocks and Molex connectors to make it fully modular and then add a glass fibre reinforcement to the coil box casing.

    At the moment the HP printer power supply shroud I have used for the coils would not stand being dropped on the floor as the plastic casing is thin and it weighs a lot . So I could make a "Chernobyl " style reinforcement shroud all around it except for the open end . The method would be simple . A cardboard "mould" box would be made up and glass fibre paste used to fill the gaps . This would make it a lot stronger and offer some protection against being dropped
  • A much better idea for the bits and pieces of Power Supply No 1 .

    This is to do what I have done before and use an old PC power supply case : this has "oodles" of space inside and can easily accommodate the bits and pieces of this supply. So I can forget about the "Chernobyl" shroud ,the coil block can be mounted with cable ties on a block of wood which can be screwed into the metal base of the case. The PCB is already on a block of wood to that is "ready to go" . I should have thought of this earlier. These supplies have low non lethal voltages: I cannot see any snags with this approach . The fabrication side of it all has been sorted !
  • But which is the primary? The one with the thick wires I assume! Mark has mentioned the enamel insulation on these windings.
    The 'voltage transformation' is in ratio with the number of windings. So the 220V side is the one with the (many windigs of) thin wires.

  • Hi Roko

    Thanks for the information . This project is just a bit of fun to see if I can actually get it to work and ask the question :- Would I actually dare to plug anything half decent into it ?
  • Using a meter on the resistance range, the primary (mains) winding should be a lot higher in value than the secondary (output) winding.
    The primary is typically 100's of ohms, the secondary is typically less than 5 ohms.

    I have a similar power supply somewhere. If / when I find it / have time to search for it, I will post a picture.

    Mark
  • Hi Mark

    Thanks for the reply

    Although continuity was OK on both windings , when I tried resistance I got a reading that went to zero pretty quickly on both windings . (Power not connected obviously). It was set ohms on both scales
  • Fitting it all inOld%20Broken%20Siclair%20power%20supply%20005_zpsrpgov5s9.jpg
  • Re above :- A pic of ZX Spectrum Power Supply (No 1) : the one that was in bits.

    Getting it all into an old PC power Supply case was a "tighter fit" than I thought. Here wooden blocks are now underneath both parts ( both the PCB and the transformer coil block ) and the wood blocks have been screwed to the bottom of the case .Also a fuse holder has been added in to the side of the metal case. The rather jagged metal protrusions on the PCB (that will be soldered to) have been secured to the PCB with Araldite as one of them was a bit loose . The Black plastic power supply holder (from an HP printer) has been secured with a cable tie which runs ,under the top of the black case , from side to side inside the case and then under the block of wood : so it has all been tied down and secured.

    The next job will be wiring it up in such a way that it can easily be taken apart again . . I will use a ceramic block and a Molex connector to achieve this.

  • The white label on the wire (and the other one one the PCB) show where one of the cables was connected to the PCB . I have no idea if the this done correctly ( someone had had a go at repairing it before and had scratched some writing onto the PCB tracking) . These old bits have their own "repair history".

  • Re the above pic "Fitting it all in" . Now the "wiring it up"

    There were too many "electrical unknowns" with this one . I got a nice flash where the negative wire was soldered to the PCB when I plugged in. Too many guesses I suppose . Nothing damaged though : probably time to give up with this

    Not like when the washing machine started making a noise and was much more expensive. I thought it was a mechanical problem but it soon turned electric and tripped out the mains . I had to be unplugged and a new machine got but it had , by then , also affected the PC which powered up for a few seconds and then switched off . This happened a few times and I ordered a new power supply . But then it cured itself and was OK so I am guessing the (modernish) surge protector on the PC must have a time delay on it which switchd it off.

    A different surge protector entirely is the one "out of a mainframe" that I got for a fiver in the 1980s to surge protect my Speccy . I got it "bare" so it had to be cased and has been doing a sterling job ever since . You can't get mainframe kit that easily these days . A pic will follow

  • The model no etc001_zpso1a2omyd.jpg
  • Re above pics : real main frame retro

    I originally saw these advertised in a magazine circa 1985 . The ad said that they were power supplies taken from from main frames that had come to the end of their lives and could be used to surge protect Spectrums . This was way before I ever saw any purpose made surge protectors in the shops so I decided to buy a couple for £5 each to protect my Spectrums . The second one was not as good as it did not have the rocker style on off switch . I have never had a problem with them . As can be seen from the above when I opened up the case it was totally sealed in so there is nothing to indicate how long it will remain in good order. .
  • This thread mostly deals with PCB bits and pieces ,PCB from Speccies or interfaces and stuff like that . I recently had a problem with one of my 128k +2 Speccies which was really legacy of unbolting it from the Opus Discovery .In the 1980s I had done an alteration and put in some extra LOAD/EAR sockets on the back on the 128 +2 case and I had not checked it since then . When checking the inside I found a loose white cable which my mod 1980s effort had probably caused all those years ago . But how would I find out the correct place to re-solder it to ? Luckily I had an un-modded Speccy of the same type so I was able to copy the PCB wiring on that which was undisturbed . Also I looked online however BUT had found very few good photos of the cabling up of this second PCB though Mark has done some good diagrams for those who can follow electric circuit diagrams .So I thought this second PCB was a bit under documented and difficult for a novice to fix So this is for people who like just copying wiring on PCB photos rather than understanding circuit diagrams . The 2 PCBs are shown one with a loose white wire and the other one which is undisturbed is the MASTER!. There are also a couple of other 128k+2 related pics:-


    https://photos.google.com/share/AF1QipMeIYJkdJbW6WpAOi-Z40qWd4WOwGSsna1mrshS9w9h_igXUZFcDAUWfHces7suMg?key=N2hVaFBtb1ZFTlR1eEVtaEJpaGZZNG82dGNaTGl3
  • And now a Song!

    (To the tune of "A drunken Sailor")

    "What do you do with an old Atari ?
    What do you do with an old Atari?
    What do you do with an old Atari early in the morning"

    Get it down from the loft my good friend
    Get it down from the loft my good friend
    Get it down from the loft my good friend , early in the morning"
  • edited February 2017
    Yes a friend of mine had got his Atari ST down from the loft and powered it up and it "almost worked" I impressed him with my knowledge about capacitors and the need to replace them bore switching on but he had already powered it up before I got there .After I gave the "advice" he gave up pretty quickly when he realized how much work /cost would be involved in getting it going again . He thought he could just swap a peripheral controller chip around and it would be fine .(Gag: My Level 1 NVQ in tinkering helped me to "come up" with this advice approach!)
    Post edited by harriusherbartio on

  • And of course he probably did not get it down from the loft "Early in the Morning" > I think he powered it up in the afternoon (Big Mistake) . Anyway he made a quip about "Not wanting to take up welding" and that was that.
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