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Thread: Help reading transistor IDs on a blurry SWR schematic.

  1. #1
    Supporting Member Axtman's Avatar
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    Help reading transistor IDs on a blurry SWR schematic.

    Can you please help me identify the following transistors?

    Here is what I think that I see:

    Q1: MPSA06
    Q2: 2N5416
    Q3: 2SC4302
    Q4: 2SC2837
    Q5: TIP29A
    Q6: MPSA56
    Q7: MPSA56
    Q8: 2SC4302
    Q9: 2SA1668
    Q10: 2SC2837

    BTW, I have "repaired" this amp before and it quit working so I cannot trust that I used the correct transistors.
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    Stray Cap DrGonz78's Avatar
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    The only one's I can't fully agree with are Q3 and Q8 as you have them 2sc4302. I read them as 2sc4382 instead. If you type in google "2sc4382 complementary pair" you will have a match with SANKEN 2SA1668 & 2SC4382 200V 2A 25W Transistor. That make sense to me that 4382 and 1668 are complementary pairs. Look at the A06 typed font on the schematic and it has a zero then compare all the 8's that could fool you as 0's.

    Edit: Also look at another version of that amp. Clearly 2sc4382.

    Click image for larger version. 

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    Don't forget the joker g1's Avatar
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    Agree on the 2SC4382.
    This drawing is mostly the same, a few different parts but uses the 2SC4382 also.
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    Lifetime Member Enzo's Avatar
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    2SC4382

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    Supporting Member Axtman's Avatar
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    See! This is why I keep you guys around.

    Thanks.

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    Supporting Member Axtman's Avatar
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    FYI Most SWR amps use the infamous Sanken 2SC3264 output transistors. This amp does not.

    If I was really industrious I could drill four holes in the chassis and mount two of those output transistors. Would there be any real advantage to doing this modification?

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    Lifetime Member Enzo's Avatar
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    Prolly not.

    By the way, I only have ONE 2SC3264 left in stock. It's real live Sanken, but lonely.

    Hmmm, I do have three of the 2SC2837.

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    Supporting Member Axtman's Avatar
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    Thanks Enzo but I just ordered parts from DigiKey because I needed a few other components.

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    Lifetime Member Enzo's Avatar
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    Oh, I am not trying to sell parts, just letting it be known when I have some maybe not so common anymore part.

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    Supporting Member Axtman's Avatar
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    I got the amp working. It's amazing what happens when you install the correct parts! ;-)

    FYI, even though this amp is an SWR California Blonde, it uses the same circuit topolgy as the Workingman 12 amp.

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  11. #11
    Lifetime Member Enzo's Avatar
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    SWR used a sort of Mix-N-Match design philosophy. They used some of their standard circuits in multiple models.

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    Supporting Member Axtman's Avatar
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    I agree. I have worked on a few SWR amps and they are all basically the same.

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