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  1. dorke

    Dishwasher Control Board Repair

    Please post the Brand and Model of your dishwasher. That way we can be of help: finding the service manual and guiding you further. Electronic parts "blow-up" because of some reason, many times not just a single device with visible damage. Finding the reason is the way to fix,not just...
  2. dorke

    tl431 calculations

    Are you talking about Rsup? What is the load current ?
  3. dorke

    Ralink 3070L adapter not responding.

    It could be a driver problem,try to reinstall the driver.
  4. dorke

    Sensor interface, OP AMP, -500mV +500 mV to 0-5 V amplifier

    I would like to add another possibility: Using a "difference amp" with the LT1366 which is a rail to rail amp. Thus can be powered with +5V in this "PH sense application" assuming an accurate +5V it can be used as a "ref" The circuit inverts the the sensor "logic" ==> 0ph=0v ;14ph=5V. The input...
  5. dorke

    Sensor interface, OP AMP, -500mV +500 mV to 0-5 V amplifier

    remarks to Bob's circuit: 1.connecting the "Ref" voltage in the "location of R2" creates an undesired effect of lowering the very high input impedance of the previous circuit with in1,in2 2.The above could still be o.k but the "output resistance" of the PH sensor has to be known and be...
  6. dorke

    Unicorn part that I can't find in any database.

    Nice find, Here (page 18) is this app diagram. Start with checking for VDD to GND voltage I would expect something like 20V
  7. dorke

    Diodes Circuit analysis

    Colin your analysis is totally wrong! "Suppose we have no input voltage on Vi. What is the state of the circuit? The voltage-difference between top and bottom is 3v. we will assume the diodes are conducting and dropping 0.7v" Wrong! the diodes are reversed bias and thus not conducting!
  8. dorke

    12vMM..what does it mean?

    It is clear to me now. The MM means Mains Monitor, that simple.:rolleyes: The signal is the "pulsating" full rectifier output(before filtering). For a 50Hz Mains it is 100Hz. Used as a HW WD to constantly discharge C8 (with the SW WD). See PIC
  9. dorke

    Getting Starting with LCDs

    There sure is, if it is 2x16 characters only as you say. In any case I would contact the company and ask them for a generic part# and manufacture . With that info you could get a replacement(original or equivalent).
  10. dorke

    Getting Starting with LCDs

    Well, here is your contact info Sangean Try getting the part from them. Good Luck
  11. dorke

    Getting Starting with LCDs

    What is the Brand and Model Number? Is it an Internet wi-fi radio?
  12. dorke

    Unicorn part that I can't find in any database.

    A sudden impact would most likely damage the transformer not the IC. Take a crisper photo of the IC,it is too blured to read the writing. I think it is a PWM controller with an integrated switching MOSFET.
  13. dorke

    Getting Starting with LCDs

    Another possibility: 1.If the radio was bought locally you can try and locate the local representative for service or parts. 2.If the radio is from a known brand, the above is possible worldwide(in theory). Sadly, In any case it will probably cost you more than buying a new radio... :(
  14. dorke

    Voltage sensor 10-15v

    I wonder... Why complicate things when they simple?:( Where does the "cooler" get the voltage to operate from? The ignition key of the truck disconnects the power to most of the electric things in it(indirectly),you can use one of this points to feed the "cooler" and the problem is solved in...
  15. dorke

    Problems with Royer oscillator and an aircore transformer

    Shouldn't the transformer work in saturation? For that you need a ferromagnetic core not an air-core..
  16. dorke

    LED power supply help

    I looked at this little bugger,and it appears to hide some little secrets...;) Our Chinese friends have put some thought about doing it cheap ... Let's take a tour::cool: The core is an IC controller of some kind The element that drive the LEDs chain is an.... SCR (PCR406) o_O There can be up...
  17. dorke

    LED power supply help

    Ianw, the controller seems to have a fuse it. Did you check it for continuity?
  18. dorke

    LED power supply help

    The simplest is to use a LM7815 15V regulaor to step down the voltage for the 555 timer and logic alone. The LEDs will be still driven by 22.8V.
  19. dorke

    Oscillator test

    What kind of oscillator is it? How are the oscillations "presented to the world "? What is the "receiving element" of the oscillator?
  20. dorke

    Impedance of two stage amplifier

    No you can not do that assumption ! Rin and Rout are independent of the way you drive the input (or output) same thing for current source or voltage source. By definition we have: Rin=Vin/Iin | Iout=0 Rout=Vout/Iout | Vin=0 example,Solving for Rin: Iout=0 ===> R4 disconnected(no load)...
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