Keithley 2400 Error: No Com Link

[cuongyd]

Dear all!
I have a 2400 device, it display "No Comm Link" error, I checked according to Keithley's repair guide, U15 & U16 are smd types and solder joints are good. What should I do next to fix it.
Thanks for supporting me!

[TiN]

Start with checking all power per repair manual. Check that memory chips still have good firmware. No com link means that front panel cannot communicate with main CPU board.

[cuongyd]

Start with checking all power per repair manual. Check that memory chips still have good firmware. No com link means that front panel cannot communicate with main CPU board.

Thank you!
I will re-check all power block.

[inse]

I also observed this behaviour on maybe two units.
After power cycle, it starts up correctly, possibly a power supply issue.
This is company property, so I won‘t investigate further.