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  1. dorke

    Amp In Protection Mode

    Could be. but the most puzzling thing is the reading of VCEsat=0v on Q605, that I have never ever seen, i.e a BJT with saturation voltage of 0.0 volts.
  2. dorke

    Amp In Protection Mode

    Please measure the voltages on both sides of D605. What do we get? As per #51, there shouldn't be that 93(K?) reading between C and E of Q605. With receiver disconnected from mains. Please remove Q605 from the board (mark it's orientation on the board for later), and measure it in diode test...
  3. dorke

    Amp In Protection Mode

    Please check resistance(non-dioed mode) of Q603 C and E to GND (with the leg of R627 lifted and not connected to anything) What do we get?
  4. dorke

    Amp In Protection Mode

    In any resistance that will show anything . You may start high ,like 2M and if it shows lower resistance set it to a lower range. After you have checked the above. Please disconnect the GND wire we have connected to the leg of R627 (820ohm/2w) and leave the leg open. Measure the voltages on...
  5. dorke

    Amp In Protection Mode

    O.K disconnect the receiver from mains. Verify there is no voltage on Q605 C,E. In diode mode test check the resistance between C and E of Q605 and reverse the probes as well. Do the same measurements in Resistance non-diode test mode. What do we get(a total of 4 measurements)?
  6. dorke

    Amp In Protection Mode

    Q605 E=C=44.1V ? Can you confirm this please.
  7. dorke

    Amp In Protection Mode

    Rick, Q601,Q603 readings look "swapped" C and E,can you please confirm that. Q605 readings are very strange and don't confirm the readings of Q601 and Q603. You see, the B of Q605,C of Q601, and C of Q603 are connected together and should have the same voltage. Here are the pinouts please...
  8. dorke

    Amp In Protection Mode

    Please measure the voltages on Q601,Q603,Q605. and R611, R615 all relative to GND. Note that Q601/603 pin-out is different than Q605 :
  9. dorke

    Amp In Protection Mode

    It's R627 not R641. D605 could be a factor, but we should check the "DC main path" first.
  10. dorke

    Amp In Protection Mode

    Sunnysky, I thought so but it isn't the case,look at #14 to #18. What I'm trying to do now is disconnect the DC loop from the output (junction of R645/647) to the Emitter of Q603, by connecting R627 bottom side directly to GND. This would create a situation in which it would be easier to find...
  11. dorke

    Amp In Protection Mode

    Rick the physical distance is not important. Simply verify there is an electrical connection between R645 and R647(ohm test)-that is the "junction". You can measure on each of the resistors where it is most convenient.
  12. dorke

    8/16 bit audio sequencer

    You can make a 16 bit "sequencer easily : cascade 2 CD4017s. it will get you 20bits. If more bits are required you can cascade more 4017s. There are audio-recorder ICs like this one and others.
  13. dorke

    Choosing the right device & circuit to convert DC to AC?

    Welcome to EP. What you need is called a "power Inverter". But your requirements are not defined properly. 1.What are you going to power with it? at what voltage? 2.There is a great difference between square and sine wave ,what should it be? 3.Define clean and stable in numerical quantities.
  14. dorke

    Radio waves question.

    This is called modulation. In this specific form shown in the video it is Amplitude Modulation (AM). The two waves are "combined by multiplication" so that the final wave is no longer a fixed amplitude signal i.e sinusoidal carrier. The amplitude of the carrier wave(produced by the alternator)...
  15. dorke

    Amp In Protection Mode

    Please put the trim-pot VR601 in the position to produce 15.6V Emitter voltage on Q601(as it was in the first place). Volume at minimum. Measure the voltage on the junction of R645/R647 (0.22ohm ). What do we get? Disconnect the receiver form mains power. Locate R627 (820ohm/2W). Find it's...
  16. dorke

    Amp In Protection Mode

    The voltages of IC601 were already tested at #4(5). The fault is of the "DC voltage on the output" type,not of the over current one. We are gradually measuring to get to the source of that problem(only on the left Chanel) .
  17. dorke

    Amp In Protection Mode

    Sunnysky, IC701 is not blown. The "second" i.e VR603 purpose is to set the idel current of the final Trs. Your explanation of Q619 and Q621 is "off bias" ;) Q619 is not a peak integrator,it is a current sensor of the final Tr Q625 (Emitter current) i.e the output current . Q620 does the same...
  18. dorke

    Amp In Protection Mode

    O.K. There is something strange in the readings of D603 cathode (46.8V) vs. B of Q601(46.7V), as the base should be higher voltage than the diode cathode.I assume it is a measurement error. Let's try this : Measure the voltage on the Emitter of Q607 relative to GND (if possible probe...
  19. dorke

    Amp In Protection Mode

    Q601 measurements make no sense. Looks like you switched C and E. R611 and R633 measurements are switched? Please confirm all measurements from #20 . Please add the the DC voltages relative to GND on D601 and R609.
  20. dorke

    Amp In Protection Mode

    The resistors are fine,I miss calculated. Please check DC voltages on both sides of D603 and R611,R633 relative to GND. Please check the voltages on Q601,It's orientation is so:
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