DS1811 reset chip: which version to use

The Dallas/Maxim DS1811 is a three-leg reset chip in a TO-92 transistor-style case that can replace most of the stock MPU reset parts. Versions differ by trip voltage: DS1811-15 at 4.13 V, DS1811-10 at 4.35 V, DS1811-5 at 4.62 V; the -10 is the one to use. Pin 1 is reset, pin 2 is +5 V and pin 3 is ground. A similar DS1233 has a 250 ms reset time against 150 ms for the DS1811.

Systems

• Bally MPU AS-2518-17
• Bally MPU AS-2518-35

Related tips

• Replace the System 80 reset circuit with a DS1811 chip
• Quick test of reset transistor Q1
• MC34064 watchdog at CPU U10: pinout and substitute
• Do not leave out the 1k pull-up when fitting a DS1811
• MPU U9 voltages that show a working reset section
• Manual reset: jumper TP5 to U9 pin 40
• Testing the MPU reset circuit at U9 pin 40
• Resets from a bad MPU J4 power connector

Source: Repairing Bally Electronic Pinball Games from 1977 to 1985, Part Two, Clay Harrell (pinrepair.com)