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Discussion in 'Radio Circuits, Repair & Performance' started by G4EDG, Dec 9, 2008.

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  1. G4EDG

    G4EDG Ham Member QRZ Page

    Hi, I'm a bit puzzled by this transistor! I'm replacing the driver transistors (2SC2509) in a TS-130s.

    The Kenwood manual says the order of the leads is B-E-C this is confirmed by studying the PCB layout. However the data sheet states the lead order is B-C-E. I obtained 2 of these transistors and can confirm their leads are B-C-E, I fitted them, swaping the C and E.........performance is poor to say the least!!!

    Have these devices changed since they were used in the TS-130s back in the 80's

    Anyone else noticed this?

    73 Steve G4EDG
  2. KA8RAW

    KA8RAW Ham Member QRZ Page

    What I would do is look at the signal of the collector and base on an oscilloscope, if the collector has a much stronger signal, they are at least amplifying. I would not think they changed spec that much. Did the manual require that the bias be set after install?
  3. KD8DEY

    KD8DEY Ham Member QRZ Page

    The ECG substitution book I have lists the ECG236 as the electrical equivalent. The ECG236 is ALSO the substitute in CB equipment as the final in SSB rigs. You might be able to try other TRANSISTORS such as the 2SC1969, OR SK3239, MRF-485

    PS the 2sc1945 uses the BEC configuration, and may possibly be a good candidate also with better dissapation than the 2509
    I Think what they sent you was a relabeled substitute. If you look on other datasheets online they list the pins on the 2509 as BEC not BCE as the part you have.
    Last edited: Dec 17, 2008
  4. KD8DEY

    KD8DEY Ham Member QRZ Page


    RFParts lists the 2sc1945 @ $7.95
  5. G4EDG

    G4EDG Ham Member QRZ Page

    Hi Guys

    Thanks for your replies! I think the 2SC2509 s I bought were fake.....this seems to be quite a problem.....try "fake semiconductors" in google. I also have a pair of 2SC1969s and a 2SC2166 from an abandoned project that I couldnt get working. These devices proved not to work in a working PA that I previously built and have used for years.

    All these transistors had a very shiny black case rather than the dull grey case of the genuine mitsubishi device. The reference "C2509" was batch number. The mitsubishi logo was distorted. The Hfe was a bit on the high side too at 190.

    Looks like I got a 2N2222 in a TO-220 case.

    So beware there is some junk out there!!

    I ended up getting a pair of 2SC1945 s from a reputable supplier, set up the bias and hey presto the PA now produces 100W.

    Thanks for your suggestions and help.

    73 Steve
  6. VK7GZ

    VK7GZ Ham Member QRZ Page

  7. KD8DEY

    KD8DEY Ham Member QRZ Page

    Glad to have been of help and that the 1945's are doing the job.
    Whadda ya know! My CB Days came in handy :D
  8. PA0PGA

    PA0PGA Ham Member QRZ Page

    Yes there are restamped, worthless RF transistors that are sold for the nice price that you have to pay for them. The high prices attract some shady people to make a easy buck I think.
    However there are brands of the same transistor with a different pin configuration, the 2sc 1945 is one of them so you have to check and double check before blowing the expensive new transistors to smithereens...
    Another problem: there is no seller that gives you any garantuee on solid-state parts, at least not overhere.

    I looked for ages to find transistors for my TS-120V,

    73 to all Wim PA0PGA
  9. KD8DEY

    KD8DEY Ham Member QRZ Page

    Sooo Did you find them?
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