Loading ...
Sorry, an error occurred while loading the content.
 

Re: Ensemble RXTX, Partially blow U9?

Expand Messages
  • jwrobles
    I had just replaced the incorrect resistor at R61 (thanks again for that help earlier) I don t know exactly what I did. In testing the installation of the RF
    Message 1 of 5 , Feb 8, 2013
      I had just replaced the incorrect resistor at R61 (thanks again for that help earlier) I don't know exactly what I did. In testing the installation of the RF I/O-switching build stage I accidentally touched a meter probe around Q3 with the power plugged in. Q3 self- destructed with a pop. Q3 was easily replaced but I then got 0 volts at the R50-R51 junction. Note that I was getting a proper 2.5V at R62, R53, R54. I replaced the FETs with great care, having learned that lesson, and am now looking at 3.25V at those same test points. I can't imagine what is going on there.

      But I will replace U9 "on principle" after checking as you and Warren suggest.

      I am VERY grateful for yours and Warren's help!



      --- In softrock40@yahoogroups.com, "Alan" wrote:
      >
      >
      > ----- Original Message -----
      > Subject: [softrock40] Re: Ensemble RXTX, Partially blow U9?
      >
      >
      > > The only recommendation I can give you at that point is to remove them from the circuit one by one until you find the one pulling
      > > the rail down.
      > >
      >
      > If it is not obvious to you Warren means gently lift the IC 5V power pins with a pin until, hopefully the faulty IC is revealed.
      >
      > Do you know why your FETs blew?
      >
      > 73 Alan G4ZFQ
      >
    • Zack Widup
      If you re only getting 3.25 volts from the regulator, it would most likely be one of two things - either the regulator is bad, or something is drawing
      Message 2 of 5 , Feb 8, 2013
        If you're only getting 3.25 volts from the regulator, it would most likely be one of two things - either the regulator is bad, or something is drawing excessive current from it.

        #2 is fairly easy to establish - as was mentioned, the regulator would get hot. And checking the total current draw of the Softrock would indicate excessive current draw.

        Actually, there's a third possibility - the voltage INTO the regulator is low. Did you measure that?

        73, Zack W9SZ


        On Fri, Feb 8, 2013 at 12:02 PM, jwrobles <jim.wrobo@...> wrote:
         

        I had just replaced the incorrect resistor at R61 (thanks again for that help earlier) I don't know exactly what I did. In testing the installation of the RF I/O-switching build stage I accidentally touched a meter probe around Q3 with the power plugged in. Q3 self- destructed with a pop. Q3 was easily replaced but I then got 0 volts at the R50-R51 junction. Note that I was getting a proper 2.5V at R62, R53, R54. I replaced the FETs with great care, having learned that lesson, and am now looking at 3.25V at those same test points. I can't imagine what is going on there.

        But I will replace U9 "on principle" after checking as you and Warren suggest.

        I am VERY grateful for yours and Warren's help!



        --- In softrock40@yahoogroups.com, "Alan" wrote:
        >
        >
        > ----- Original Message -----
        > Subject: [softrock40] Re: Ensemble RXTX, Partially blow U9?
        >
        >
        > > The only recommendation I can give you at that point is to remove them from the circuit one by one until you find the one pulling
        > > the rail down.
        > >
        >
        > If it is not obvious to you Warren means gently lift the IC 5V power pins with a pin until, hopefully the faulty IC is revealed.
        >
        > Do you know why your FETs blew?
        >
        > 73 Alan G4ZFQ
        >


      Your message has been successfully submitted and would be delivered to recipients shortly.