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need help with my Betson Imperial trackball
PL1:
--- Quote from: Zkam on July 12, 2024, 03:16:28 pm ---Hi. I belief the LED on both optos are dead. I could not see anything, even with the digital camera. I found a set of Wico Trackball Opto Boards.
They fit perfectly in the case. Will these work as well?
--- End quote ---
The LEDs for each pair of optos are wired in series so if one of the pair goes bad, they both stop working.
Another way to test LEDs is using your multimeter set to diode check.
- Red lead on the anode (triangle) end. Black lead on the cathode (line) end.
Those Wico boards should work with your MiniPac.
- Give me a while to reverse engineer the pinout for them.
Scott
PL1:
. . . and here is the pinout for the Wico optical board.
The IC is a 74HC14AN Hex Schmitt-Trigger Inverter.
- The output of a Schmitt-Trigger ignores floating voltages. It only changes state when the input fully changes state. i.e. HIGH to LOW or LOW to HIGH. This "squares up" the output.
- Inverter means that if you apply a logic HIGH to an input you'll get a logic LOW on the output.
- The IC is there to reduce backspin due to high frequency roll off (application a - see related post here) and noise that can cause jitter. (application b)
R3 is the current limiting resistor for the opto LEDs.
R1 and R2 are pullup resistors for the opto data lines.
Scott