Recent content by Guy Shemesh

  1. Guy Shemesh

    In depth guide to PCB Vias and PCB design

    Hello friends I have written a detailed guide on PCB vias. The concept of the via is intuitive and could be easily understood, however in order to design the most suitable via for a specific board requires profound understanding of the PCB manufacturing process. The cost of the PCB...
  2. Guy Shemesh

    Question electrolytic capacitor

    As I said, they dry out..
  3. Guy Shemesh

    Question electrolytic capacitor

    The epcos informaion is only valid for epcos 🙂 Electrolytic capacitors from 1990 is generally something to beware of. They contain liquid or gel electrolyte which basically dries out over time. from 1990 up to now its 30+ years, I'd say that failure is quite certain. Moreover, the failure can...
  4. Guy Shemesh

    Camera 6v power supply

    Hi Dave,  Yes you can, just make sure you get the polarities right. You need to verify that the + of the battery goes to the + of the camera, and same for the -.  Typically electronic circuits are protecting against this but you shouldn't try it.  Just check your old battery and make sure the...
  5. Guy Shemesh

    hyland 0-30v psu output osillates

    Hi Paul Check your VRef circuit around U1, it seems very suspicious to me. To which Vref voltage you are designing for ?  I would replace this small circuit altogether.. seems like a mistake in the schematics there.  Best of Luck Guy ePiccolo Engineering
  6. Guy Shemesh

    TL494 half bridge smps

    Hi,  A full diagram would have been more helpful to understand the circuit, with your provided circuit its hard to tell. You need to specify at the very least the other pins 16 and 3 of the TL494. However from the point of connection alone - trimpot touching the 0.1 ohm sense resistors - it...
  7. Guy Shemesh

    Repairing my Studio Microphones

    You are very welcome 😀
  8. Guy Shemesh

    Help identifying electronic components

    That would be the best! Good luck
  9. Guy Shemesh

    Help identifying electronic components

    Oh!  I'm sorry to see this, looks like there is further damage. The caps are severely damaged..  No I would not recommend to try and save this board.  I would let it go
  10. Guy Shemesh

    Help identifying electronic components

    Hello Jim, I think the fix would be fairly easy, assuming that P6 is the only diode that got burned. If the failure propagated elsewhere in the circuit there might be more damage but my gut feeling says you have a really good chances here.  Looking at the Viper IC I see it is self protected...
  11. Guy Shemesh

    Are looking for new good information about electronics?

    By the way, an extremely useful and free tool can be downloaded from here:  saturnpcb.com/pcb_toolkit It does require installation on the PC, and it groups many useful PCB calculators in one program.  I have no connection to it, other than using it. enjoy
  12. Guy Shemesh

    Repairing my Studio Microphones

    Sounds like you are already on your way 😀 Regarding schematics, some very well known mics have their schematics published, for example you can google "neumann u87 schematic" or "schoeps microphones schematic". The information is there..  I wish you much success with your efforts. Guy
  13. Guy Shemesh

    H Bridge PWM DC Motor Driver + PCB

    It looks very nice, I also like the layout and the fact you used polygon pours on both sides.  I think one improvement would be to make edge plating on the sides, it helps dissipate the heat off the main board. If you can add schematics to the post that would also be interesting to see.  Thanks
  14. Guy Shemesh

    Repairing my Studio Microphones

    Hi Peter. It's quite a difficult question to answer, since building microphones can be a full time profession. I'd start with the dynamic microphones first, in these there is usually not much electronics inside - there is the transducer and usually a transformer. So with good hands and a good...
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