Optical trigger

Ask questions about DIY board assembly issues, fault finding and testing. (Covers all Megasquirt versions and board.)

Moderators: jsmcortina, muythaibxr

Post Reply
cukali
Experienced MS/Extra'er
Posts: 196
Joined: Tue Jun 08, 2010 8:59 pm

Optical trigger

Post by cukali »

Ok, now I am feeling totally noob again...

Three boards.. 2 MS3s and one MS2...trying to trouble shoot the optical input for one of them and I cannot get the system to work on any of them.

I scoped the U3 and I get a good wave on pins 1 and 4 but it will not pick up rpms. One board I just assembled today (to replace one with short...see other thread) but now none of the boards are working using optical input and they worked just a few days ago. Guess my brain is fried from 4 straight days of banging it on the wall....lol




If I hook a 1k ohm resistor directly to pin 5 from optoin (using 5v sesnor) it picks up rpms and works fine for all boards. When I use a pull-up resistor from 5v to optoin it doesnt work. I want this working and dont want to have to use VR in...pots are a pain to adjust in car with MS3x.

please help


thnx
Matt Cramer
Super MS/Extra'er
Posts: 17499
Joined: Thu Apr 16, 2009 8:08 pm

Re: Optical trigger

Post by Matt Cramer »

Can you clear up what component pin 5 is on?
Matt Cramer -1966 Dodge Dart slant six running on MS3X
Post Reply