Darlington transistors (D2449 & B1594) replacement

Discussion in 'General Electronics Chat' started by sixtoraymundo, Apr 15, 2008.

  1. sixtoraymundo

    Thread Starter New Member

    Apr 15, 2008
    I have a Kenwood Karaoke amplifier model KA-KA600 which damaage it,s power transistors. According to some sources this transistors already does not exist. any replacement can anybody suggest.
  2. Audioguru


    Dec 20, 2007
    Your Japanese part numbers are incomplete. Maybe they are 2SD2449 and 2SB1594.

    Look at the spec's for the transistors in their datasheets then select similar ones that are available. You might need to adjust a bias current trimpot.
  3. sixtoraymundo

    Thread Starter New Member

    Apr 15, 2008
    you are right it is 2SD2449 & 2SB1594. have already inquired from manufacturer which isToshiba and production was stopped.( obsolete) Any suggestion is very well appreciated since I am not really well versed in Electronics I am an electrical practitioner by profession tnx
  4. mrmeval

    AAC Fanatic!

    Jun 30, 2006

    Failing that the 2sd2449 data sheet is here http://zeta.octopart.com/Toshiba__2SD2449__0.pdf

    I assume it's a match to the other transistor. Find a matched pair of NPN/PNP darlingtons that meet or exceed the specs. In some cases you can disregard some of the specs but it's been a long time since I did repair. I've modified, replaced or manufactured heatsinks to match the replacement transistor.

    Sometimes you need the schematic so you can modify the circuit to use replacement parts which is not trivial. This is not something I do but I do know someone that was an audio god when it came to reviving 1970's and earlier audio equipment.

    In some cases the manufacturer will be more than happy to help. In a lot of cases they will send (for a fee) the parts AND any other parts (yep fee) and bulletins that show what you need to do to prevent blowing the parts again. You'd have to contact the technical side not the customer service side.

    One 10 cent part can blow 100 dollars worth of output parts.
  5. sixtoraymundo

    Thread Starter New Member

    Apr 15, 2008
    Thank you very much for the suggestion. I'm looking now for a file of a transistor cross reference manual to have a direct or cross substitute for my damage part.