From: Daniele Gratteri (daniele_gratteri_at_inwind.it)
Date: 2002-04-09 19:14:38
----- Original Message ----- From: "Ray Bryan" <email@example.com> To: <firstname.lastname@example.org> 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 boards. > 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 an LS?). Can you confirm that UC1 is the '14 and UD1 is the '06? Many thanks, ____ __ / ___|____ Daniele Gratteri, Italian Commodore and Amiga user /// | | |___/ E-MAIL: email@example.com __ /// | |___|___\ IRC: FIAT1100D - ICQ: 53943994 \\\/// \____| URL: http://spazioweb.inwind.it/danielegratteri \/// Message was sent through the cbm-hackers mailing list
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