Beomaster 6500 CPU

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  • #7853
    rrm
    BRONZE Member
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    Which CPU does a BM6500 use (serial begins with 08)? I suspect the CPU could be defect as the BM6500 does not start up from standby. Replacing caps and battery on the CPU board did not help. Is the spare CPU still available?

    • This topic was modified 3 months, 2 weeks ago by rrm.
    #7861
    Die_Bogener
    BRONZE Member
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    The cpu is a 80C32 chip. Jep, there are still a lot of them available… but most are not compatible with the old one.

    It must be a Philips 80C32 BPN (!!!)

    Not compatible are 80C32x2 … they are working faster, there are timing problems.

    Have you checked 5V on the cpu board? Best point is the Eprom 27512… Pin14 GND and Pin28 5V.

    Was there a Service RESET done… if battery changed? (!!!) Otherwise it will not respond!

    #7870
    Dillen
    Moderator
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    Could also be a Siemens SAB8032A-P or a third type I don’t recall right now.
    You will have to look inside.
    When you know the type ask at Beoparts-shop. Even if not listed, quite often old stock can
    be found there which is much better than buying asian counterfeits off Ebay etc.

    Martin

    #7890
    Die_Bogener
    BRONZE Member
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    Siemens, Philips, Intel are OK.

    ATMEL is not ok. To modern…

    It must be a standard 80C32 CPU, not with extra additional ram… just 256 internal Bytes. No additional Eprom or ROM or extended RAM beyond 256bytes. No extra Timer.

    Not Atmel 80C32x2 because faster…

    I prefer Philips, just because of asian counterfeits… intel and Siemens are more expensive or some people get more of your money for nothing.

    Martin No.2

    • This reply was modified 3 months, 2 weeks ago by Die_Bogener.
    #7903
    rrm
    BRONZE Member
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    Thanks both for the expert advice. I am glad to hear that the Beomaster can likely be repaired even if the CPU has died. The Beomaster has been reset after backup battery replacement and worked for a while, yet in an unstable manner with poor IR reception, freezing (mains power off required to restart), and loss/overwrite of programmed radio stations and sound settings.

    #7934
    Die_Bogener
    BRONZE Member
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    Do you have access to a datalink connection?

    I had a 8032 cpu with a defect INTerupt pin… meaning that IR is working bad. I connected the master to a MX TV-set… and all was working fine. Exchange of the cpu and the master was ok.

    But: use a good socket. It can happen again. The reason is a missing z-diode on the INT pin, causing a small overload during communication. I added a 5,6V z-diode…

    And: check the keramic caps near the connectors. There were problems with them, mechanical stress is not good for them.

    Also the connector on the front-IR board is very often corroded, causing erratic flickering of the display data.

    Martin 2

    #7943
    rrm
    BRONZE Member
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    Thank you Martin 2 for additional hints to the troubleshooting. Yes, the Beomaster could be operated via Datalink when unresponsive to the remote commands or the front panel buttons. Now when it cannot turn on from standby there is no response via Datalink either.

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