-------Original Message------- > From: "Declan Moriarty" <[EMAIL PROTECTED]> > Subject: What was it? > Sent: 26 Jan 2005 00:31:23 > > I have a CPU Controller card (8085 based, vintage �1987). The motor blew on > the machine, power surges came and went, and now it won't communicate > with the outside world. One chip is totally (I mean tetotally) > destroyed, right beside the serial port. The com port on the relevant pc > has also been blown, beacuse it was connected at the time. > > What was it? I know it's Texas Instruments, silver topped (SN something) > and 14 pin. It's partner in the RS232 circuit is a 75152 (a Line > Driver). On this mystery chip, pin 7 is 5V ground, Pins 4, 9, 12 are to > the 5V circuit. Pin 4 was really blown off the chip, and there sure was > some heat around. Miraculously, the machine (A huge Turret Punch) > > Has anyone a memory long enough to remember how these circuits were > configured? I am used to MAX 232s with electrolytics around; this board > has no capacitors in sight. No power supply onboard. How did they do > RS232 back in those days? > >
A common technique was using the pair MC1488/MC1489. These are quad NAND type line drivers with level shifting. They do not need caps (no charge pump inside), but requires bipolar supply. Yours is probably SN75188, the TI variety of MC1488. Regards Rahul www.voltsmith.com -- Author: rahul INET: [EMAIL PROTECTED] Fat City Hosting, San Diego, California -- http://www.fatcity.com --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB CHIPDIR-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
