Great spot
Doh it is indeed an opto that functions correctly - must’ve missed that off of the colouring. Sorry.
Single Phantom Switch -WPC-S -SOLVED
- Thread starter James
- Start date
Doh it is indeed an opto that functions correctly - must’ve missed that off of the colouring. Sorry.
I had weird intermittent opto problems on my twilight zone a few years back. Opto boards get very hot. Turned out that there was a tiny, requiring a magnifying glass to see it, break in an opto board track.
It might be worth going pin to pin on your opto board checking continuity between every soldered joint to wherever the track leads you to.
Can you swap in a known, working, opto board ?
Clean/ swap out the troublesome rollover switch and try a new one in there ? Or at least, swap it with one of the known working switches in your game
It might be worth going pin to pin on your opto board checking continuity between every soldered joint to wherever the track leads you to.
Can you swap in a known, working, opto board ?
Clean/ swap out the troublesome rollover switch and try a new one in there ? Or at least, swap it with one of the known working switches in your game
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Before
After
I tested all the resistors and they matched up except this one...
R33 starts off at 18.1 the rises to around 21.5 slowly. Below comes straight in at 21.6...
continuity even with some clear solder issues was good.
After
I tested all the resistors and they matched up except this one...
R33 starts off at 18.1 the rises to around 21.5 slowly. Below comes straight in at 21.6...
continuity even with some clear solder issues was good.
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resistor values don’t change like that. i guess you are charging a capacitor on the board with the meter. reverse your meter probes and remeasure all.
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ps the board you are looking at isn’t that the 10opto board? that handles the optos in columns 4 and 5.
your issue is with column 3 opto. on the other opto board!
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your issue is with column 3 opto. on the other opto board!
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Intrigued to see what you find.......
trying to logically think it out:
the way the switch matrix works is it strobes each column. for a column to be active it is Low. all the other columns are high.
the system then scans each row in turn looking for a row that is low. if it is the switch at that col/row is on or closed. ie the row has been dragged low by a switch being closed linking it to the column which is low.
the opto switches are different to a normal switch inasmuch as they go through a different extra set of logic circuits that pull their output low if the beam is made.
what is happening in your situation is your 33 opto is working correctly until 63 is closed. this is somehow dragging the row high at a time when column 3 is active.
but strangely not for the optos in cols 4 and 5 ? but they are driven off a different board,the 10opto board, whereas col 3 driven off the 7 opto trough board.
so that suggests a combination of a weakness in the low signal on the col 3 opto, maybe it’s not strong enough AND some leakage of high signal via switch 63, so either a shorted, reversed or slightly faulty diode.
Sent from my iPhone using Tapatalk
the way the switch matrix works is it strobes each column. for a column to be active it is Low. all the other columns are high.
the system then scans each row in turn looking for a row that is low. if it is the switch at that col/row is on or closed. ie the row has been dragged low by a switch being closed linking it to the column which is low.
the opto switches are different to a normal switch inasmuch as they go through a different extra set of logic circuits that pull their output low if the beam is made.
what is happening in your situation is your 33 opto is working correctly until 63 is closed. this is somehow dragging the row high at a time when column 3 is active.
but strangely not for the optos in cols 4 and 5 ? but they are driven off a different board,the 10opto board, whereas col 3 driven off the 7 opto trough board.
so that suggests a combination of a weakness in the low signal on the col 3 opto, maybe it’s not strong enough AND some leakage of high signal via switch 63, so either a shorted, reversed or slightly faulty diode.
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What a bitch!
Is that a rogue blob of solder on that floorboard thing?
