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  1. Ylli

    Marantz SM500DC - defective

    OK, that is correct. Strange - the schematic shows the lamps in series, but the board layout shows them in parallel. If they are in series, then if one burns out, they all go out. In parallel each is independent. F801 is a fuse in the line driving the lamps, but if you see 8 VAC on the lamps...
  2. Ylli

    Marantz SM500DC - defective

    Service manual here: https://www.hifiengine.com/manual_library/marantz/sm500dc.shtml Where are you seeing 68 volts? I see rail voltages of +/-46 volts. Are all the fuses good, including F801? F801 feeds the lights, which look to be 6 bulbs in series. Most likely, the protection circuit...
  3. Ylli

    Silent electric motor to drive turntable.

    This is what I was going to suggest, except coupling with a mechanical linkage that does not involve gears.
  4. Ylli

    NAD CD Player front panel buttons dead!

    Nuttree, this is a old thread and you might want to start a new one for your issue. The manual for the NAD C-565bee is here: https://www.manualslib.com/manual/1391226/Nad-C-565bee.html
  5. Ylli

    12vDC to 24vac module needs modification

    Output is 24 V p-p differential (across both outputs). If you look at either output in reference to ground, you will only see 12 V p-p. The two outputs are out of phase so differentially, you have 24 V p-p.
  6. Ylli

    Domestic amp keeps blowing 3.5amp fuses

    Even solid state devices do not have an infinite lifetime. Sometimes they just fail. ...Or it could have been a power surge, or an overtemp (too loud for too long). But we don't know for sure it is a bad output transistor, but checking these would be the first step.
  7. Ylli

    Domestic amp keeps blowing 3.5amp fuses

    Most likely you have a blown output transistor. Do you have reasonable soldering skills? It looks like these are TIP3055 parts in a TO-246 package. Either totally remove, or lift the legs of all four of these and check with your ohmmeter.
  8. Ylli

    Domestic amp keeps blowing 3.5amp fuses

    Service manual: https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=2ahUKEwiov8iPsvbkAhVDJKwKHS43CCkQFjABegQIARAB&url=https://www.manualslib.com/manual/997449/AAndr-A60.html&usg=AOvVaw057oZJ5K5klKxw64LlvG1X Which fuse(s) are blowing? The 'Mains fuse', the...
  9. Ylli

    Zener Voltage Regulator to power Arduino

    If you need 500 mA, then you would not want to use a simple shunt zener regulator. Have you considered a voltage regulator IC such as an LM7805?
  10. Ylli

    Zener Voltage Regulator to power Arduino

    Resistor will dissipate 0.49 W and the diode will dissipate 0.35 W. You would need to use at least a 1W resistor and a 1 W Zener (1N4733). If the circuit oinly draws a few mA, you could probably increase the resistor to more like 330 or 470 ohms and things won't get as hot.
  11. Ylli

    ID a circuit please

    Sure looks like a home made board too.
  12. Ylli

    Chassis mount 10W resistor value

    2.5 ohm, 10W, 10%
  13. Ylli

    Analog Circuit to Randomly Modulate Amplitude and Frequency

    You are asking for output variations that an engineer usually works hard to avoid. An oscillator is normally designed so that the output frequency and amplitude are as insensitive as possible to the supply voltage. So I guess if you want the frequency and amplitude to vary with supply...
  14. Ylli

    Comedy Thread

    12
  15. Ylli

    Power consumption of reverse-polarity protection diode

    You may really have an issue there. Attached excerpt from the data sheet. The SB540 is a 40 volt part, so you are operating it at about 9% of ratings. At 25°C, the leakage is around 6-7 uA. At elevated temperatures, it gets worse. If it is possible to change the diodes, you could probably...
  16. Ylli

    Can I find the value of these coils ??

    This is an remote control transmitter? Guessing the part you have labeled Hn43B is likely an encode, followed by a gated oscillator and a matching network/filter to the antenna. The surface mount inductors look to be 0805 (2012 metric) sized. You can not determine the inductance value from...
  17. Ylli

    2A3/ VT4-C Amplifier Design help

    The data sheets on the tubes give an approximate bias voltage requirement. You really think this thing is worth rebuilding?
  18. Ylli

    Fuse length and you! For your health!

    Yeah, sorry about just seemed that knowing how fast canon fuse burns had more to do with 'health' than a mis-sized electrical fuse.
  19. Ylli

    Fuse length and you! For your health!

    Typical canon fuse burns at a rate of about 3 seconds per inch.
  20. Ylli

    What is this?

    The device on the top looks to be a US Quarter. If you have 50 of these, the value is nominally $12.50.
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