(Topic ID: 211721)

LM741 in U9 that works for a Bally -32 sound board

By Joydivision

6 years ago



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    #2 6 years ago

    I don't think you will find any new make 741 that works in that board. I have tried LM741 by national and they didnt work. Where did you buy it at? I think TI bought national semiconductor in 2011... so 741 that work in the -32 are probably old stock.

    Download the Dolly Parton Manual and add the extra circuit on the 741 that isnt in the -32. Two 10k resistors dividing the 12v in half + a 1uF smooth cap. Not that bad of a job to fit the new parts. You can drill a few holes in the board.

    #5 6 years ago
    Quoted from Joydivision:

    I bought them from an ebay seller, he only had 4 units. These look like they would be similar though, even an older date code, that is if they send the same ones in the pic, good old Polida...
    ebay.com link » 10pcs Op Amp Ic Nsc Fairchild Dip 8 Lm741cn Lm741cn Nopb
    After I read somewhere where you worked out a late 70s 741 chip like the original was needed to work I tried to find some, the ebay seller I bought from had some national chips with an 80s date I thought I would try, he ended up sending me the 08 date ones instead which to my surprise worked.

    You likely got a remark from Polida. That means the pulled that chip off of an old PCB. Sanded down the top and put a new imprint on it. The picture even looks like they roughed up the top of that chip.

    GPE is a bit over dramatic about the Chinese resellers. In this situation getting an old remark was actually a good thing since you didnt have to mod the board. Have fun

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