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2sa684 replacment

Discussion in 'Pioneer Audio' started by Tod denneny, Feb 4, 2018.

  1. Tod denneny

    Tod denneny New Member

    Messages:
    42
    hi being looking for a replacement but i need it in a to-92

    here is what i found ksa1281
    or ZTX956STZDICT-ND

    anyone could please confirm thanks so much
     

     

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  2. petehall347

    petehall347 the brandy coffee man Subscriber

    Messages:
    28,126
    Location:
    uk.. the middle bit
    the 684 is 60v . ztx 50v .. depends on what its job is and if 50v high enough .
     
  3. sregor

    sregor AK Subscriber Subscriber

    Messages:
    3,586
    Location:
    Mass
    KSA1013 TO-92L like 2sa684 package. 1A ic max. All other specs equal or better.
     
  4. markthefixer

    markthefixer On Hiatus, dealing with Dad's estate full time Subscriber

    Messages:
    21,125
    Location:
    Bensenville,Illinois
    Not until you tell us what model and what position the original was used in. Until then it is a crap shoot.
    We have no way of knowing if current or gain or voltage is the predominant factor, no less speed or dissipation as secondary dominant factor.
    For THAT we need to know where it was / is / will be...
     
  5. Tod denneny

    Tod denneny New Member

    Messages:
    42
    I have reproduced this board and made the error of not using a to 220 for the 2sa684

    upload_2018-2-5_8-17-32.png
     
  6. kramden

    kramden Active Member

    Messages:
    162
    Board says SX-1250
     

     

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  7. Hyperion

    Hyperion Roobarb & Custard Subscriber

    Messages:
    48,631
    Location:
    Hertfordshire, UK
    Yes, but on what board in the SX-1250 and what position on that board - i.e. the circuit reference - this is very important to answer your query accurately.
     
  8. avionic

    avionic " Black Knights " Subscriber

    Messages:
    44,683
    Location:
    Fort Dodge, Iowa
    Board says AWR-106 . Appears to be power supply. -25vdc pass transistor Q8.. Only 2SA684A on the board. Not to tough even for this old Yamaha guy to figure it out.:rolleyes:
     
    Last edited: Feb 5, 2018
  9. Tod denneny

    Tod denneny New Member

    Messages:
    42
    yes your right :)
     
  10. Tod denneny

    Tod denneny New Member

    Messages:
    42
    i got three 1250 here all need this board to complete them....i made other boards before for sansui units all worked perfect. Takes a shit load of time but when you can find them you make time :)

    i always build to original spec when i can
     
  11. zebulon1

    zebulon1 Building a new bench. Finally! Subscriber

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    I like it. Some of the boards I've worked were butchered.
    What heatsinks are you planning?
     

     

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  12. Tod denneny

    Tod denneny New Member

    Messages:
    42
    Digi-Key Part Number HS404-ND

    ya that the problem many boards are butchered

    I also made the 091 board for the 1250 working perfectly ... Good thing i like doing it each board takes about two week to do. then prototype test and produce
     
  13. zebulon1

    zebulon1 Building a new bench. Finally! Subscriber

    Messages:
    4,918
    Location:
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    Very, very nice.
    Thanks for the contribution to these fine Pioneers.
    Glad we'll have an option.
     
    Tod denneny likes this.
  14. markthefixer

    markthefixer On Hiatus, dealing with Dad's estate full time Subscriber

    Messages:
    21,125
    Location:
    Bensenville,Illinois
    edit - not an error, a TO-220 in the SX-1250 AWR-106 Q8 (-25v 16mA) position would be overkill to the point of introducing problems (gain and base draw from the zener reference for one). A TO-126 with enough overhead to fit a small clip on heat sink would be almost overkill but just my style...


    Ah HAH, the -25v series pass element on the SX-1250 's AWR-106 power supply "stabilizer assembly".
    1 mA to the protection's DC differential detector, 15mA to the preamp circuits.

    I take it that the board already exists? Nice....

    That on-semi's voltage is a bit low, on fault or unexpected conditions, it can see higher voltage, especially at sub 16mA currents, the
    1.5k resistor won't keep the voltage under 50 - you are running a razor thin margin at the collector there...

    Current 16mA, not a lot of extra draw expected. That's about 350mW assuming the -65v and a 1.5k (2w) dropping resistor. Their own calculations and reported voltages on the schematic calculate out to a 12 mA current (65 - 47)/1500 = 0.0012A, not the 16 mA shown on the main schematic...

    Hmmm...
    512-KSA1013YBU to-92L ecb 160v 1a .9w 100mhz 160-320hfe $0.34 (R=60-120, O=100/200, Y=160/320)
    I / my posted parts lists for the SX-1250 use the TO-126 cased KSA1220
    512-KSA1220AYS to-126 ecb 120/a160 1.2a 1.2w/20w 175mhz 35-320hfe $0.39 (R=60-120, O=100/200, Y=160/320)

    The 1013 will fit the real estate, the 92L case will help with the dissipation, although I would LIKE to see the ksa1220 there, but if it don't fit....
    oh well...


    Will the boards be open sourced like AK's STK-0050 replacement, or available commercially like TxTurbo's SX-1980 AWR-154 Power Supply board?

    Kudos to sregor on the quick and first KSA1013 response!!! (credit where credit is due!)
     
    Last edited: Feb 5, 2018
  15. Tod denneny

    Tod denneny New Member

    Messages:
    42
    Yes the original schematic i created had the Ksa1220 forgot to change the package before i sent it to production :(
    I could correct it and send to production again but costly so i was looking for the best alternative.

    I am going to try the 1013 then test when in operation and if i have any issues i will just send out for new boards.

    Thanks so much for the reply

    PS i will have two extra boards available if anyone is interested
     
  16. markthefixer

    markthefixer On Hiatus, dealing with Dad's estate full time Subscriber

    Messages:
    21,125
    Location:
    Bensenville,Illinois
    I really wouldn't expect any short term problems with the 1013, my thoughts that put the KSA1220 in there were towards the far future and the philosophy of keeping transistors cool enough to touch and happy... The 1013 will be at about 1/3 max dissipation, so when well ventilated, using it wouldn't keep me up at night...
    I'd love to BORROW a board, for form/fit examination. The connectors especially have roused my curiosity BIG time!!!
     

     

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  17. Tod denneny

    Tod denneny New Member

    Messages:
    42
    This is the 091 protection board if anyone is interested they will also be available
     

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  18. Tod denneny

    Tod denneny New Member

    Messages:
    42
    Digi-Key Part Number 277-1955-ND connectors and they work really well
     
  19. markthefixer

    markthefixer On Hiatus, dealing with Dad's estate full time Subscriber

    Messages:
    21,125
    Location:
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    Oh, I see - no pins.

    No more unplugging the board,no pins/connector stuff, cut off the connector on the end of the chassis wiring and use screw terminals just like TxTurbo's SX-1980 AWR-154 Power Supply board.
     
  20. zebulon1

    zebulon1 Building a new bench. Finally! Subscriber

    Messages:
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    Location:
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    What about a design that can utilize the old pins from the toasted board?
    It maybe too late but it would be nice.
     
    Tod denneny likes this.

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