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  1. (*steve*)

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    No, disconnect the secondary. Is it the surge when the filter caps charge? What is the total capacitance of your filter caps?
  2. (*steve*)

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Does it happen with no load on the secondary? And presumably the fuse fails immediately you turn the PSU on (i.e. not after a couple of second delay).
  3. (*steve*)

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Use a higher rated fuse. Alternatively find a fuse with a longer delay (TT, TTT,...) If you're using an NTC thermistor to limit the switch on current, then rapidly cycling the power also won't let it cool down. Another option is to have a resistor in series with the mains, and a relay to...
  4. (*steve*)

    Tin plating

    There are a number of alternatives. The pre-made liquids are typically quite expensive. The dry chemicals generally have a short lifetime once mixed (and they're not cheap). The raw chemicals are orders of magnitude cheaper (even in comparatively small quantities). I'm trying to have a...
  5. (*steve*)

    Tin plating

    I've been mucking about with diy tin plating and here are my latest results. I mixed up enough solution to about half full this beaker. Measuring 0.025g of one of the reagents was probably the hardest bit. And here are the results The playing on the left was a result of a few minutes...
  6. (*steve*)

    Dyson DC24 Brush Roller DC Motor PCB

    Because a resistor is cheaper. To provide sufficient voltage or power rating. In some circuits it can also be used to reduce parasitic capacitance, but that would not be the case here. Use your multimeter on the resistance range and measure their resistance. Tell us what they read. It may...
  7. (*steve*)

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    That is most definitely a slow blow fuse. Fuses of that type should probably be able to sustain a 200% overload for some time between 2 and 120 seconds. The example below has *exactly* that specification, but yours should be similar. See here.
  8. (*steve*)

    Realistic STA-2100D

    Excellent general photos. The first thing if check is that the stereo/mono switch results in switching seen on the board. The simplest fault is a faulty switch or broken wires. Whilst these may not be common, they're the easiest to fix. Detailed photos of the FM board from both sides with...
  9. (*steve*)

    Realistic STA-2100D

    Maybe. I'm not familiar with this device. Also post links to any service manuals. Does the receiver produce a stereo signal, or just mono (i.e. is the FM receiver correctly decoding stereo and not displaying the indication, or failing to decode at all)?
  10. (*steve*)

    Realistic STA-2100D

    Turn the volume down so you don't have to shout at us. That 70mV and 50mV, I presume that was across the output? Maybe some pictures would help.
  11. (*steve*)

    Dyson DC24 Brush Roller DC Motor PCB

    It will act as a fuse To provide sufficient voltage or power rating. In some circuits it can also be used to reduce parasitic capacitance, but that would not be the case here. It almost certainly has a role in reducing the electrical noise generated by the motor. However it's main purpose...
  12. (*steve*)

    Replace 9Volt Battery with Solar Panel

    I would also consider contacting the local Mormon church, expressing some interest, and asking that they send some missionaries around to talk to you. When they arrive, have the laddar and all the other stuff out and pretend to have forgotten they were coming. Ask them to give you a hand while...
  13. (*steve*)

    Amplifier

    Do you mean "replaced by a coupled transformer"? It is always helpful if you or both circuits. Is this homework?
  14. (*steve*)

    How exactly does a capacitor charge?

    A capacitor and a leyden jar work in the same way. "charging" (some people prefer "energising") consists of altering the electrical charge either side of an insulating dielectric. In a practical sense, the capacitor as a whole has a neutral electrical charge (it does not lose or gain electrons...
  15. (*steve*)

    Sony 300cd changer reads track number on CD incorrectly ?

    Does it do it with every CD? What is the discrepancy? It's new, have you contacted the retailer/manufacturer?
  16. (*steve*)

    Secret Mission Motion Sensor

    What about deliberately creaky floors? Or PIR sensors mounted on the back of your head? Or mirrors on all the walls?
  17. (*steve*)

    Monitor problem on/off switch

    It is likely that the switch has come to the end of its useful life. I would consider replacing it. There is an electronic circuit that monitors this switch. When you press the button it toggles power. This is called a "soft power switch" and it means that power is always turned on when the...
  18. (*steve*)

    Successful Stanford Research SR530 lock-in amplifier repair

    I believe the latest US aircraft carriers are using these to launch their manned weapons platforms (aka aircraft). I also believe they're not having a good time of it. Old fashioned stream is simple and well understood, but I hope they can get them working because retrofitting conventional...
  19. (*steve*)

    Successful Stanford Research SR530 lock-in amplifier repair

    Now I have successfully repaired the second lock-in amplifier, is there anything I can do with two of them that I can't do with one? I'm still waiting for the special triple half H-bridge controller (a fancy gate driver for 6 MOSFETs) before I build my chopper.
  20. (*steve*)

    Got any ideas for using an old fridge?

    How about you probably the lid up at 45 degrees and add fake triangular teeth to the body and the lid. Then you can also pretend that a great white shark has eaten your fish.
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