In file “@400000005eea6aa110e82fa0.u”, there are a large number of I2C communication bus failure entries:
2020-08-03_02:12:32.82461 1457827 ERROR: i2c_transfer: ioctl failed (110: Connection timed out, src/i2c.cpp:26)
2020-08-03_02:12:32.83577 1457834 ERROR: Head I2C communication alert (src/hw_task_messages.cpp:333)
2020-08-03_02:12:32.83580 1457834 ERROR: Board I2C communication alert (src/hw_task_messages.cpp:322)
2020-08-03_02:12:33.33462 1458337 ERROR: i2c_transfer: ioctl failed (110: Connection timed out, src/i2c.cpp:26)
2020-08-03_02:12:33.84547 1458848 ERROR: i2c_transfer: ioctl failed (110: Connection timed out, src/i2c.cpp:26)
2020-08-03_02:12:34.35462 1459357 ERROR: i2c_transfer: ioctl failed (110: Connection timed out, src/i2c.cpp:26)
2020-08-03_02:12:34.86461 1459867 ERROR: i2c_transfer: ioctl failed (110: Connection timed out, src/i2c.cpp:26)
2020-08-03_02:12:35.37666 1460379 ERROR: i2c_transfer: ioctl failed (110: Connection timed out, src/i2c.cpp:26)
2020-08-03_02:12:35.88462 1460887 ERROR: i2c_transfer: ioctl failed (110: Connection timed out, src/i2c.cpp:26)
2020-08-03_02:12:36.39462 1461397 ERROR: i2c_transfer: ioctl failed (110: Connection timed out, src/i2c.cpp:26)
2020-08-03_02:12:36.40584 1461402 ERROR: fused_temp: could not read board temp sensor (src/sensor_task_peripherals.cpp:397)
The “Head”, “Interconnect”, and “Board” all share the same I2C bus. A problem on one board or connector will likely impact them all. I put together a description of the I2C buses on the Glowforge, if you’re interested in the details.
First thing I would inspect is the ribbon cable connected to the head. That is notorious for wearing through due to the rough underside of the black panel that “protects” it. That cable carries the I2C bus to the head, and open/shorted bus lines would be problematic.