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  1. dorke

    Please explain circuit

    @AK, You are wrong here again. There is feedback.look better. Anyways,why do you think the feedback should be "each stage -Q output back to its D input" ,where does this come from! It isn't a shift register!
  2. dorke

    Please explain circuit

    Yes absolutely ! or " logic 1"
  3. dorke

    Please explain circuit

    The 4017 is not a shift register , internally it is a 5 stage synchronous Johnson counter ! Why do you think it's a shift register?
  4. dorke

    Obsolete Hewlett Packard Transistor

    From the service manual It is a PNP 40Watt T0-220 manufactured by HP designation Q2. Is this part of the power supply? Can you post the schematics ?
  5. dorke

    Please explain circuit

    We are dealing with binary logic devices,which have 2 possible levels. The inputs and outputs are defined to be: "0" or "false" "1" or "True" "low"(for "0") and "high"(for "1") are also used . They are the indication of the voltage level of the logic states. These voltage levels can be of...
  6. dorke

    Is this an inductor?

    Most probably a 39nF/250V capacitor. The 393 is the value =39000pF=39nF.
  7. dorke

    Please explain circuit

    Well,The terms are a bit off.;) "Basically, the clock pin gets its power from the outputs that are high from previous button pushes." The clock pin doesn't get "power". The clock pin advances the count on positive signal edges i.e. the transition from "0" to "1". This is achieved by closing...
  8. dorke

    Please explain circuit

    Hop, "As for switch bounce, the first "legal" transition that results in a valid clock pulse will advance the counter and remove the voltage to the switch. Who cares if the switch contacts bounce after that?" No that thinking is absolutely wrong(both in theory and in practice) !!! The voltage...
  9. dorke

    Obsolete Hewlett Packard Transistor

    This site has it for 5$ and this one for 3.6$
  10. dorke

    Is this an inductor?

    Don't think so. The "flat structure " and color look more like a polyester capacitor. The photo is useless,please post a good quality one.
  11. dorke

    Stereo buzz until unit warms up

    It is an Onkyo isn't it? They suffer from a lot of heat related problems in ICs as well.
  12. dorke

    Anyone use this rework station?

    I 'm using this Saike 8858 digital hot air blower. Very pleased with it for SMD and shrink tubing. I paid 52$ on Ebay about 2 years ago. The one you posted looks similar but "all analog control". the price is very good. Don't know the build quality,probably worth the "risk". There are many...
  13. dorke

    Please explain circuit

    @(*steve*), It is a bad design conceptually ,since the synchronous counter is clocked A-synchronously. The problem boils down to 2 things in this specific case: 1.Would the minimum, clock duration tW of the 4017 be maintained in all cases? 2.Is it possible to get 2 or more activating low to...
  14. dorke

    Stereo buzz until unit warms up

    If possible replace the bad caps with "computer grade" caps of 105C (temperature) , and take care not to get Chinese counterfeits ,don't by them on Ebay !
  15. dorke

    Please explain circuit

    The 4017 can be described as a "1 out of 10 ring counter". In other words there is always one output with a "1" while all others are at "0". Pressing any one of the 6 "Master reset" switches S5-S10 will put the 4017 counter in the "0" state, meaning pin #3 is at"1". The correct sequence will...
  16. dorke

    Please explain circuit

    I don't like this "lock"design at all: 1. It as a single "hard wired code" ,would be very difficult to change it-requires hard rewiring . 2. It has no limit for the number of trials allowed. 3 .Clocking a counter directly with non debouched push-buttons , leads to erroneous operation.
  17. dorke

    Capacitors

    Hop, There is a little, but very important fact about capacitance: It is a geometrical property ! In fact the unit of capacitance in the cgs unit system is centimeter [cm] !!!
  18. dorke

    Capacitors

    @biferi, I hope you are not discouraged by the "bombardment" of the forum members(including myself;)). Keep asking,that is the only way to learn... anything you need to make it as clear as possible for you. Here is a water analogy: Larger container volume is equivalent to larger capacitance...
  19. dorke

    Technics SA-828 - Static with audio, then stopped working

    Please measure the DC voltages relative to chaises GND on IC1002 (TA7317 ) it is a SIP 9 pin device. And both sides of D1001 relative to chaises GND .
  20. dorke

    Capacitors

    The relation is Q= I *t or I=Q/t And since we also have Q=C*V we get I=C*V/t So for a fixed time interval and voltage I1=C1*K ; I2=C2*K Thus I1/I2 =C1/C2 So if C1=25 ,C2=13 the 25 uF may give you 25/13 "more current" than the 13 one.
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