Cyrus 3 Schematics

Discussion in 'User Manuals, Service Manuals and Schematics' started by Tenson, Mar 28, 2011.

  1. Tenson

    Tenson Moderator

    Joined:
    Nov 12, 2003
    Messages:
    5,947
    Likes Received:
    1
    Location:
    Kent, UK
    1. Advertisements

  2. Tenson

    Ladislav

    Joined:
    Oct 19, 2014
    Messages:
    4
    Likes Received:
    0
    Location:
    Czech republic
    CYRUS 3 HA7A Schematic

    Hallo,
    i'm repairing CYRUS 3 HA7A3124 (date 9311)
    Transistors in L final stage and driver was burned.
    With new transistors sometimes OK,
    sometimes on output occures -12 to -20 V DC.
    Also in stby, CCS off, LED pwr flashes orange.

    Schematics from Tenson are for CYRUS HA7Z.
    HA7A ist different. Final stage quasi complementar,
    CPU 40 pins DIL, diffferent numbers of components.

    Please, has anybody the right schematics for me?

    Thank you, Ladislav
     
    Ladislav, Oct 19, 2014
    #2
    1. Advertisements

  3. Tenson

    Ladislav

    Joined:
    Oct 19, 2014
    Messages:
    4
    Likes Received:
    0
    Location:
    Czech republic
    Problem solved

    With removed final transistor still orangre flashing LED PWR and -20V on output.
    Defective was SMD transistor T539.
    Short protection was permanent activated and over R614 and T539 came
    -20V to output. (Without loudspeakers.)

    I've T539 replaced, though i think, it has no function in this circuit.
    Transistors T539 and T541 should work as a thyristor.
    Whenn one transistor switches, output current holds both transistors
    permanently in switched status. (Till energized)
    But here is output current limited by R614 to maximal 0,86 mA.
    Ube of T541 on R523 and R525 parallel is under 0,2 V.
    Si transistor needs minimal 0,6 V.

    Ladislav
     

    Attached Files:

    Ladislav, Oct 27, 2014
    #3
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.