Fwd: [roys-tech-chat] Building replacement for TTL counter DM8552 (National Semiconductor)

Have any of you guys ever heard of this chip? It's new to me... ---------- Forwarded Message ---------- Subject: [roys-tech-chat] Building replacement for TTL counter DM8552 (National Semiconductor) Date: Thursday 10 April 2008 08:58 From: "Michel" <itloiiw at yahoo.com> To: roys-tech-chat at yahoogroups.com Hello all, I am trying to repair a Systron Donner Frequency Counter model 6254 that does not count well. This counter is build with "simple" TTL chips only. (I have no manual nor schematic). The culprit (found by swapping chips) is a TTL chip from NS : DM8552 It is a decade counter with latches and tri-state outputs. Since I did not find any source for replacement chip, I have thought to build some equivalent circuit with maybe 74LS160 and 74LS393. My problem is that I have no datasheet except pinout for DM8552 (found there http://www.datasheetarchive.com/pdf/1215336.pdf ). Does anybody have more information about it ? Many thanks in advance, Michel Grenoble - France. ------------------------------------ Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/roys-tech-chat/ ------------------------------------------------------- -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin