More Studer B67 work trying to figure out what’s going on.
I don’t remember what prompted me to do that, but I decided to turn the right hand roller guide by hand when the supply motor is the responsive one. Turns out, it turns off the supply motor and turns on the take up motor.
My friend instructed me to test the MOVE voltage at the right sensor PCB.
I taped both tape lifters in the UP position (to trick the machine that there’s there’s tape threaded, I believe). Then I checked the voltage between J1-2 and J1-1 in these different scenarios:
Pressing PLAY and turning the roller by hand: +4.78 VDC.
Machine in STOP and turning roller by hand: +4.78 VDC.Machine in STOP and roller is still: +0.03 VDC.
FIY these three voltages are what should be expected (essentially +5VDC when there’s tape “moving” and 0 VDC when no tape is moving).
Then I turned to checking the voltages on IC8 on the transport board. This is a pain because I had to remove the transport again.
All voltages are with respect to pin 7 which is ground.
Pin 6 was constantly at -0.53V regardless of the machine being in PLAY, STOP, and the roller spinning or still.
In STOP mode, pin 4 measured 4.31 VDC when the roller was spinning and 0.12 VDC when the roller was still.
In PLAY it dips to 0.12 VDC and quickly goes up to 4.23 VDC (roller not spinning). Spinning the roller makes it go down to 0.12 VDC.
Still not sure what this all means. I’ll update when I do!