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  1. Tha fios agaibh

    isolating transformer and variac - what order?

    Doesn't having earth (neutral) wired straight through negatate the whole (safety) reason of an isolation transformer? I agree with the practice of putting the Isolation xformer first.
  2. Tha fios agaibh

    Grundig YB500 World receiver fixup and panelbeat

    Right. I'd at least replace e caps in the nasty area. The others are probably not long for this world due to their age.
  3. Tha fios agaibh

    Speaker wiring came loose. Need help with connections

    Yes, that jumper threw me for a loop also.
  4. Tha fios agaibh

    Speaker wiring came loose. Need help with connections

    Yes. Or probably easier to hook to the same highest point on left 1/4"jack (positive). By the way, If you look at the 1/4" jack on left, both the tall prong and bottom left wire are both the same pos connection. In other words, either point could be used.
  5. Tha fios agaibh

    Grundig YB500 World receiver fixup and panelbeat

    Wow, didn't realize there was that many. I just saw this portion which looks to me like the caps might have lost some juce.
  6. Tha fios agaibh

    Speaker wiring came loose. Need help with connections

    The short black wire comming from top right jack is neg input and should go to 1/4" jack beneath it with the other black wire. I presume the wire with white trace on far right of picture goes to positive tip or tallest point of same 1/4" jack with just solder on it.
  7. Tha fios agaibh

    Grundig YB500 World receiver fixup and panelbeat

    Nice job bushtech. Your technique seems to be working well. Even if you accidentally break a trace, you do have pictures to reference. I'm guessing the bluish color is the copper oxidation? Probably wise to replace all the electrolytic caps. One of them looks like it might be leaking.
  8. Tha fios agaibh

    Grundig YB500 World receiver fixup and panelbeat

    Ipa is always good served chilled, (India pale ale). I have cleaned circuit boards by rubbing with a pencil eraser or using baking soda and a small fine scotch bright pad. You will probably have to remove some components to do a decent job. Also try electrical cleaner solvents like no-flash. I...
  9. Tha fios agaibh

    Have a little fun...

    I'm not familiar with the programming language but it tooks like it learns a patern depending on the first light that comes on. Then it learns by either dec or inc (decrease or increment?) the variable by one which determines what light comes on? If that's true, the observer can't choose the...
  10. Tha fios agaibh

    Have a little fun...

    I don't get it. Even if you had an excellent memory, how would you input one of....what?, 40 Possibilities into the machine?
  11. Tha fios agaibh

    Have a little fun...

    But it says observers can pick any order they wish. Therefore sequence isn't predetermined. The order of colors has to be input to the controller somehow.
  12. Tha fios agaibh

    Have a little fun...

    Ok, I imagine it's possible to make the lenses addressable to have the switches follow, but how could it follow the rubber cap colors on the switches? Magnets? My mind will be blown until I see a schematic or get an explanation.
  13. Tha fios agaibh

    PSU help please.

    On some power supplies. You can limit the current at a specific voltage, but you can't exceed what current the load normally draws. For instance, you could set the voltage at 12v and hook-up a 12w light bulb that draws 1 amp. Then you can vary the current from 0-1A but can't exceed 1A. Is this...
  14. Tha fios agaibh

    Fuse rating for electric car heating system?

    Pull the old fuse and look at the markings on the metal end of the fuse. I wouldn't use a 500v ac rated fuse for 400v dc. There's a chance it could arc over and not safety clear a fault. I have heard the "1/2 the ac rating" rule of thumb and although its not an accurate calculation, it seems...
  15. Tha fios agaibh

    Whirlpool Oven Control Board Fault

    Not likely. Relay contacts could stick on, but usually stay stuck. Might be a problem with a nearby circuit that drives the relay. Perhaps a shorted component? You could solder small wires on the relay coil so you can monitor its signal remotely if necessary.
  16. Tha fios agaibh

    PSU help please.

    Without more details its hard to say. The 30a rating may be its peak rating. If you had a heavy resistance across it, perhaps voltage dropped because it was overloaded. Cheaper switch mode power supplies don't like to start under heavy loads. I recommend buying a Linear type power supply with...
  17. Tha fios agaibh

    On a D.C. power supply.

    Often yes, but it doesn't have to be. You could ground the Positive side, or ground the power supply mid-way between Pos and Neg to divide the voltage between the two with respect to ground. For example you could read 12v between Pos and Neg, so you've got -6v on Neg and +6 on Pos with respect...
  18. Tha fios agaibh

    Two relays in series with flyback diode.

    Yes
  19. Tha fios agaibh

    Two relays in series with flyback diode.

    It seems you've answered you own question. As close as possible to the relay coil. I would solder a short piece of wire to one end of diode if leads won't reach.
  20. Tha fios agaibh

    diode question

    Great question. I'd say you can have them in parallel provided they are on the same heat sink to keep their temp rise close. An advantage would be that you can draw more current, but certainly not 10x the rating of one diode. I would guess closer to 3 or 4x? Seems to me, you'd be better off...
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