Announcement

Collapse
No announcement yet.

TGSL-VLF ///just ask!

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • #76
    Hi Galal
    The most common fault for no or lack of -5v on the tgsl build todate is the transistor pinout connections there are at least 4 different common pinouts on those transistors infact me myself got caught out with the very same thing in the early days.
    What you need to do is read all the information on the transistors and google them for pinouts.
    Ie: could be 123: EBC, CBE, BEC ,CEB the first two combinations are the most common depending on manufacture.
    Theres somewhere on the earlier part of the TGSL forum where the likes of me, Ivonics and a few others grabing them from are stocks and comparing the different pinouts, and we were shocked at the amount of variations.
    By the way your not allowed to give up and throw in the towel, we dont except failure in Geotec, we just carry on and make things work.

    If you got problems with id post me all the markings on the trs and will check them out for you.
    Regards

    Comment


    • #77
      2N2907 and 2N2222 (plastic cases) are usually having EBC pin order, atlhough there are metalic ones with CBE order.
      Once i experienced similar problem. I tried everything and later discovered 4024 was failure.
      So you can replace 4024 too.
      If TX coil is ~6mH, TX caps are 220nF and 22nF (like on schematic) than you will be able to measure 14-14.6kHz frequency at 4024 pin 1.
      It is than divided by 4024 and there is 1/2 of it at 4024 pin 12.
      If this is correct than only possible failure can be at those transistors and the rest of components there. Maybe some leakage at electrolytics? Maybe some reversed diode?

      Comment


      • #78
        ok,before i go to the uni and recheck the oscillator,i will make sure that pinouts of the trs are correct,this photo show what i had doing,is this pinouts correct?
        Attached Files

        Comment


        • #79
          Originally posted by galal View Post
          ok,before i go to the uni and recheck the oscillator,i will make sure that pinouts of the trs are correct,this photo show what i had doing,is this pinouts correct?

          If those are in plastic case than answer is: most probably NO.
          It is EBC than.
          Besides; why are we trying to solve this like that? You can use hfe measurement at your uni and distinguish proper pin assingments.
          Only when properly inserted - transistor will show some hfe.
          Give it a try.

          Comment


          • #80
            Originally posted by galal View Post
            ok,before i go to the uni and recheck the oscillator,i will make sure that pinouts of the trs are correct,this photo show what i had doing,is this pinouts correct?
            Use a multimeter with an facility to measure transistor hfe. Athough testing in this way is no guarantee that the transistor is any good, it does enable you to easily find the correct pinout.

            Comment


            • #81
              guess what i found,when i focused on the number of the trs,i found that it's not P2N2222 and P2N2907 it's PN2222 and PN2907 and its datasheet shown that its pinouts EBC not CBE,and you use P2N not PN,what is difference between them in the performance,can that effect on the circuit and -5v?

              Comment


              • #82
                Originally posted by galal View Post
                guess what i found,when i focused on the number of the trs,i found that it's not P2N2222 and P2N2907 it's PN2222 and PN2907 and its datasheet shown that its pinouts EBC not CBE,and you use P2N not PN,what is difference between them in the performance,can that effect on the circuit and -5v?
                The P2 versions are in a metal can TO-18 package, whereas the PN versions are in a plastic TO-92 package. Otherwise they're exactly the same.

                Comment


                • #83
                  Originally posted by ivconic View Post
                  If those are in plastic case than answer is: most probably NO.
                  It is EBC than.
                  Besides; why are we trying to solve this like that? You can use hfe measurement at your uni and distinguish proper pin assingments.
                  Only when properly inserted - transistor will show some hfe.
                  Give it a try.
                  Ivonics we have had this discussion before the plastic ones i have are CBE thats why if you look at my project photos somewhere on TGSL my transistors all look the same way round unlike some other plastic 2n2907/2n2222 on other engineers projects that are kissing each other, im not going down this road again like previously, just warning the lad not to take pinouts for granted.

                  Comment


                  • #84
                    Originally posted by Qiaozhi View Post
                    The P2 versions are in a metal can TO-18 package, whereas the PN versions are in a plastic TO-92 package. Otherwise they're exactly the same.
                    My findings were that with the metal housings type trs made the detector chatty like when moving wires around, any movement gave the symptoms of dry joints, when replacing back to plastic to92 everything was back to perfect stability. This again I posted in the TGSL forum in the early days.

                    All this is going back to what i said earlier on this thread, read the ...... TGSL project pages and do your homework, its all there in black and white.
                    Make a list of all your questions and doubts then its simple just read whats already been answered and sorted out many times.
                    Dont mind helping people but you got to help yourself also.

                    Regards

                    Comment


                    • #85
                      Originally posted by galal View Post
                      ok,before i go to the uni and recheck the oscillator,i will make sure that pinouts of the trs are correct,this photo show what i had doing,is this pinouts correct?
                      So who or where did you get the pinout connections from?, they may well be right, but theres just so much chance either one or both could be wrong so theres a 25% chance your right, so hope now you get my meaning, its thing learned from old, you cant take things for granted in the component world, even the manufactures sometimes get it wrong let alone the constructer.
                      My gut feeling tells me this could well now be at least one of your problems.

                      Regards

                      Comment


                      • #86
                        Originally posted by satdaveuk View Post
                        Ivonics we have had this discussion before the plastic ones i have are CBE thats why if you look at my project photos somewhere on TGSL my transistors all look the same way round unlike some other plastic 2n2907/2n2222 on other engineers projects that are kissing each other, im not going down this road again like previously, just warning the lad not to take pinouts for granted.
                        You are absolutely right!
                        There are indeed numeorus manufacturers which do obey different standards.
                        Situation is even more complicated nowdays when we have many unknown manufacturers from China!
                        I met mostly EBC pin order at plastic ones, but that doesn't mean that all of those must be the same.
                        Most probably there are different ones. And i guess that also depends of local supplier and it's sources.

                        Comment


                        • #87
                          Maybe this can help:

                          http://www.edaboard.com/thread106051.html

                          Comment


                          • #88
                            Hi dear friends,you was right jerry,I have found the problem,first all trs is ok and I connect them correctly in the board,now I have minus voltage but remain -3v,what I did is disconnected everything at minus supply except ICs and some things without this things there's no minus supply,but the voltage still -3v,and i became separate ICs one by one until IC U102a,when I disconnected U102a minus volt became -6v,that mean the problem with U102a right? should I change it? I think this problem is almost dissolved.

                            Comment


                            • #89
                              Originally posted by galal View Post
                              Hi dear friends,you was right jerry,I have found the problem,first all trs is ok and I connect them correctly in the board,now I have minus voltage but remain -3v,what I did is disconnected everything at minus supply except ICs and some things without this things there's no minus supply,but the voltage still -3v,and i became separate ICs one by one until IC U102a,when I disconnected U102a minus volt became -6v,that mean the problem with U102a right? should I change it? I think this problem is almost dissolved.
                              That is great news! Now you know where to concentrate your attentions. As to what the problem with U102 is, it could be a bad chip, wrong chip or plugged in backwards. It could be something else but those are good things to check first.

                              Jerry

                              Comment


                              • #90
                                i have checked it and i see that i should to change it,but i use 393P not 393AN and the same with another ICs,no problem in that? is there difference between P and N or AN

                                Comment

                                Working...
                                X