 |
| char lines line up with the bigger resistors |
there is a touch of charring under the resistors, but they all check out. Ran continuity between solder points to check traces, diode tests, all seems ok.
With it installed, the switch edge tests are fine. The optos work as they should, but opto #2 will also register when a coil is fired.
WHAT COULD BE GOING ON WHERE A VARIATION IN THE VOLTAGE ACROSS THE BOARD WOULD GIVE A FALSE-POSITIVE ON ONE OPTO, BUT NOT THE OTHERS?
Reflow the optos, I would likely do the resisters and headers for the connector as well. If the opto is intermittent, it's usually because of a cracked solder connection, which is next to impossible to see on the small optos solder points.
ReplyDeleteThere isn't actually any intermittency with it's operation, it's very consistent:
DeleteWhen the drop target is up, it registers as open.
When the drop target is down, it registers as closed.
When the drop target is up, and a solenoid fires, it registers momentarily as closed.
So I really think it's just the transmitter/receiver opto that's gone wonky.
That's intermittent. If it works all the time, it's good, if it works none of the time, it's bad, if it works some of the time, but not always, that's intermittent. This is always because of cracked solder joints. Components, when they are bad, stop working.
ReplyDeleteThe vibration from the solenoid is knocking jarring the weak solder connection for a second, and causing a switch to appear registered.
Guess who should have never ever doubted you? THIS GAL!
DeleteThanks, re-flowed solder on most of the board and it solved the issue.