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Marantz 250M Power Amp Service Bulletins

Discussion in 'Marantz Audio' started by Pete B, Nov 6, 2018.

  1. Pete B

    Pete B AK Member Subscriber

    CT, USA
    I found Service Bulletins (SB) 2-5 for the 250M not the 250 in the digital database Marantz (page 10)
    section of AK, they are free for download: http://akdatabase.com/AKview/index.php
    M-250-2 Mar 26, 1975 New part numbers for specific transistors and rules for beta selection
    M-250-3 Aug 16, 1976 Increased reliability by replacing pre, driver, and output transistors.
    Add flyback diodes, bias and test unit.
    M-250-4 Sept 24, 1976 Correction to bias setting in M-250-3, sets current to 1/2 of previous.
    M-250-5 Nov 15, 1977 New part number for power transformer and how to replace a failed one.

    The 250 manuals can also be found there but much earlier in the database.

    Anyone have SB M-250-1 ?


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  2. angusdog

    angusdog AK Subscriber Subscriber

    Hey Pete.I see you are here also.
  3. rickl

    rickl Active Member

    Twin Cities
    Pete, I have form No. 199-1074. Not sure if this is what you are looking for or this is something listed above.

    Attached Files:

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