Re: Problems with a long board 1541

From: Daniele Gratteri (
Date: 2002-04-09 19:14:38

  • Next message: Ray Bryan: "RE: Problems with a long board 1541"
    ----- Original Message -----
    From: "Ray Bryan" <>
    To: <>
    Sent: Tuesday, April 09, 2002 12:22 AM
    Subject: RE: Problems with a long board 1541
    > The long logic board had all discrete logic instead of the large logic
    array of
    > those later boards, but this sounds like 7406 or 74ls14 on the serial line
    in has
    > failed (a common occurence).  The same thing happens on the shorter
    > On that board they are labeled UD1 & UC1 - check the pins with a scope or
    > logic probe.  on UD1 the pins are paired as - 1-2,3-4,5-6, 9-8, 13-12,
    > the out pin should always negate the input - if input changes and output
    does not
    > or output=input bad gate
    This is an interesting thing: I cheched UC1 and UD1 and found that,
    probably, they had already been substituted in the past since solderings are
    different from the other ones. But, damn, they haven't installed sockets!
    I have desoldered both UC1 and UD1 and I will put in new parts as soon as
    possible (at the moment I only have a 7414: could it work, also if it isn't
    LS?). Can you confirm that UC1 is the '14 and UD1 is the '06?
    Many thanks,
      ____                                                             __
     / ___|____   Daniele Gratteri, Italian Commodore and Amiga user  ///
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