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  1. Ylli

    Marantz SM500dc repair, help?

    - or + 1.5 vdc on pin 5? Since you said the output is at -12 volts, I'll assume you measure it as -1.5 volts. If that is the case, the output of this op-amp, pin 7, should have ramped down to - 15 volts or so. Might be a bad op-amp. Both of them the same at +37.5? So 1.5 mA total tail...
  2. Ylli

    Marantz SM500dc repair, help?

    -12 VDC at output not good. Let's get a few voltage readings and see what we can figure out. Please measure the voltage (reference to ground) at the following: Q709 pin 5 Q709 pin 7 Q701 emitters Q701 bases Q701 collectors Voltage *across* R713 Voltage *across* R737 Oh, and let's get the rail...
  3. Ylli

    Technics SA-5760 Receiver No Output

    Yeah, really no current in either side of TR601. You need enough current through the input side of TR601 to develop about 1.5 - 1.8 volts across R611. This will start to turn on TR603/TR607 pulling the output back down towards zero. There may be something else we are not seeing, but at this...
  4. Ylli

    Campervan tv aerial conundrum

    MCX? If so, then...
  5. Ylli

    Technics SA-5760 Receiver No Output

    Well, let me explain my reasoning and maybe something else will jump out..... The power bus across the top (left hand side of R683) you have labeled as +58.4 volts. I assume the negative bus in this area (bottom end of R613) is at around -58.4 volts. I didn't ask for a measurement, it could...
  6. Ylli

    Technics SA-5760 Receiver No Output

    I think the right hand side of TR601 has a collector to emitter short. Check the collector-emitter resistance with an ohmmeter - in circuit is OK. The service manual lists it as a 2SA798. As for a source of that part, I see one ebay listing at...
  7. Ylli

    Campervan tv aerial conundrum

    Does the socket on your tuner look like this: And the coax from your antenna look like this:
  8. Ylli

    Technics SA-5760 Receiver No Output

    So it appears there is no current through the input side of the diff pair TR601. Let's measure voltage at the wiper of R601 voltage at TR601 emitters voltage at TR601 input base and feedback base Voltage across R613 On the original drawing, are the blue or the black labels the faulty voltage...
  9. Ylli

    Technics SA-5760 Receiver No Output

    What is the voltage on the collector of TR607? What is the voltage across R611?
  10. Ylli

    MISSING POWER SUPPLY FOR LCD STRIP LIGHT

    Sure looks 'Molex' to me, but I can't find an equivalent online.
  11. Ylli

    Self-Burnt CD problem

    Neither the radio in my car nor the DVD player hooked up to my TV have USB ports. I need CD's for the car and DVD's for the TV. Back before I retired, none of the newer computers we were issued at work contained a floppy disk drive. Well, a lot of our RF test equipment did, and dumped the...
  12. Ylli

    Relay testing

    A 24 VAC source and a 24v lamp would be the safest. Higher AC voltages with an appropriate load are OK, but be carefull.
  13. Ylli

    Rpm Problem turntable Sony PS 333 direct drive

    Do as kellys_eye say, but I'm going to suggest a different path. Please measure the DC voltage on each of the three pins of Q4 and post them.
  14. Ylli

    Relay testing

    Data sheet here: https://www.mouser.com/datasheet/2/404/s-13904.pdf No simple way to test it. You could apply an input to the 'coil' of the rated 7 - 30 volts and be sure it draws a little current. May be as low as 1 mA. The output side, you will need to provide an AC voltage and a load...
  15. Ylli

    help! Unknown prong type!

    12 volts DC is not going to be right for that 12 VAC synchronous motor. Even though the original plug is polarized, the 'guts' (consisting of a synchronous motor and what looks like a xenon reflector lamp) need 12 VAC. Those xenon lamps can draw a bit of current too, so probably 12 VAC 3-5 amps.
  16. Ylli

    GPS Satellites Visible But No Fix

    3mm, that translates to a time accuracy of 10 ns or better. That deserves a WOW.
  17. Ylli

    Something zapped it

    Good point *steve*. In addition, the TS might want to disconnect both speakers, turn the unit on, and use a voltmeter to confirm no (or minimal) DC voltage is present on the speaker outputs.
  18. Ylli

    Something zapped it

    Schematic snippet: These are the main left and right channels, and I assumed one of these has the failure. Or is it in the 'surround sound' or 'back channel' output?
  19. Ylli

    Something zapped it

    If it is working with headphones, that points to the speakers. You said one of the speakers was blown out, and then said only one side was working. How did you make that diagnosis? If you have one working speaker left, connect it to the left channel output - do you get sound? Now connect it...
  20. Ylli

    Aiwa stereo model CX - N3200U

    Won't blow up or catch fire, but the radio sound, both AM and FM depending on which you 'adjusted', may be adversely affected.
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