Post Reply 
1826-0287 chip
11-17-2016, 12:07 AM
Post: #1
1826-0287 chip
Hi all,

This chip seems to appear in the printer type calculators like HP-19C and HP-10

It seems to be a mystery. Anyone ever find out what it is for?

cheers

Tony
Find all posts by this user
Quote this message in a reply
11-17-2016, 12:26 AM (This post was last modified: 11-17-2016 12:37 AM by Dave Frederickson.)
Post: #2
RE: 1826-0287 chip
According to the HP-97 service manual, it's a quad comparator used in the motor speed control circuit. See para. 2-28 for a complete description. The 19C schematic by Tony Duell identifies it as an LM339.
Find all posts by this user
Quote this message in a reply
11-17-2016, 04:59 AM
Post: #3
RE: 1826-0287 chip
(11-17-2016 12:26 AM)Dave Frederickson Wrote:  According to the HP-97 service manual, it's a quad comparator used in the motor speed control circuit. See para. 2-28 for a complete description. The 19C schematic by Tony Duell identifies it as an LM339.

Cool, thanks Dave.
Find all posts by this user
Quote this message in a reply
Post Reply 




User(s) browsing this thread: 1 Guest(s)